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Abstract
To cope with the physiological demands of soccer, players must be competent across several fitness components. The use of fitness tests in the laboratory and field assist in examining soccer players' capabilities for performance both at the amateur and elite levels. Laboratory tests provide a useful indication of players' general fitness. Accurate test results can be obtained with the use of a thorough methodology and reliable equipment. Laboratory tests are used sparingly during the season because of the time-consuming nature of the tests. Instead, tests are generally carried out at the start and end of the pre-season period to evaluate the effectiveness of specific training interventions. Field tests provide results that are specific to the sport and are therefore more valid than laboratory tests. The reduced cost, use of minimal equipment and the ease with which tests can be conducted make them more convenient for extensive use throughout the season. Although data from laboratory and field tests provide a good indication of general and soccer-specific fitness, individual test results cannot be used to predict performance in match-play conclusively because of the complex nature of performance in competition. Fitness tests in conjunction with physiological data should be used for monitoring changes in players' fitness and for guiding their training prescription.
... Since it is difficult to measure oxygen uptake during real soccer games, the values for oxygen uptake are often based on heart rate values and their relationship with oxygen uptake during simulated soccer drills in laboratory, where factors like hyperthermia, dehydration and stress are taken into consideration [1,10]. For soccer players, maximal aerobic power is important for the ability to play for 90 min, and for the recovery between the short bouts of high-intensity exercise [12][13][14]. However, due to the discrepancies in the activity patterns and the underlying physiology associated with soccer match play, VO2max is not a sensitive enough measure for physical performance in soccer [12]. ...
... For soccer players, maximal aerobic power is important for the ability to play for 90 min, and for the recovery between the short bouts of high-intensity exercise [12][13][14]. However, due to the discrepancies in the activity patterns and the underlying physiology associated with soccer match play, VO2max is not a sensitive enough measure for physical performance in soccer [12]. ...
... The rather high blood lactate that appears in soccer, therefore, may not be due to lactate production in a single action during a game, but represent an accumulated response to a number of high-intensity activities [15]. However, with respect to soccer, the lactate threshold does not appear to be strongly related to physical performance during match play or to performance during an intermittent field test [12,17]. Degradation of creatine phosphate (PCr), and to a lesser extent stored adenosin triphosphate (ATP), provides a considerable amount of energy during periods of high intensity during a match [1, 14,18]. ...
Soccer is the most popular sport in the world, played by approximately 275 million people, over 128,000 of whom are registered as professionals (FIFA Professional Football Report, 2019). In a soccer match, the outfield players are organized in numerous formations in and out of possession based on tactical instructions from the coach. Performance in soccer is determined by the players’ technical, tactical, physiological and psychological/social characteristics. Soccer players who have the ability to cope with the physical demands of the game can utilize their tactical and technical skills more effectively during match play. Understanding the physical demands of soccer is important in order to optimize the training process. Over the years, numerous techniques have been used to determine the physical profile of soccer players. Observations of athletes while they participate in their specific sport may provide useful data on the physiological demands of an activity.
The overall objective of this thesis was to investigate the physical demands of elite soccer players, with special focus on high-intensity movements and actions. In order to investigate the overall objective, this project wanted to characterize the sprint and acceleration profiles of elite soccer players and investigate whether the number of accelerations constitutes a more precise estimate of match physical performance and performance decline in elite soccer players compared to high-intensity running (HIR) distances, as well as whether small-sided games (SSGs) in training could give a high enough training load for high-intensity movements and actions. Finally, the aim was to obtain knowledge concerning player load using accelerometers and the patterns of player load during matches, and how different soccer-specific high-intensity actions influence physiological, perceptual and accelerometer loads.
This thesis suggest that accelerations may be a more stable and sensitive measure of physical performance decline compared to HIR distance in soccer match play. Time-motion analysis is a useful tool for examining the physiological demands from high-speed activities, but accelerometers may supply information concerning player load from the many discrete actions of a soccer match that may be classified as low-speed activity. Indeed, the present thesis reveals some new factors concerning player load during matches. This thesis also suggests that many high-intensity actions without change in location at the pitch may contribute significantly to player load during matches and training. Player load from accelerometer may function as a complementary tool to investigate player loads during matches and training in addition to other tracking systems. Furthermore, the similarity in player load patterns between both matches and positions in elite soccer competition could indicate a physical “pacing pattern” employed by elite soccer teams. Training with 4 vs. 4 SSGs seems highly valuable to provide the peak demand for accelerations and player load during matches, but neither 4 vs. 4 nor 6 vs. 6 SSGs are close to the HIR or sprint demands during matches.
... Soccer is considered the most popular sport in the world, particularly among younger people (1)(2)(3)(4), consisting of intermittent exercises with high intensity (e.g., running with quick changes of direction, starts, sudden stops, jumps, shots) interspersed with periods of low-intensity exercise (2,(5)(6)(7). ...
... In this context, field tests are considered an adequate alternative to laboratory tests (8,9), namely because of their suitability for the sport, low cost and ease of implementation. According to these aspects, it will allow its frequent use during the competitive season (7). ...
... It is important that there is objective information about the players' physical performance to guide the planning and objectives of the training process and thus optimise their performance. These data can be obtained through tests that assess the levels of physical fitness, whether in the laboratory or the field, in this case, more directed towards specific aspects of the sport (7). In this way, numerous tests have been developed to assess the physical abilities of players, both in detecting talent at training levels and in controlling the training process (11). ...
Introduction
Soccer is considered a multifaceted collective sport, and to reach an elevated level, players must have moderate to high power, good agility, joint flexibility and muscle development. Also, players must be able to generate high torques during fast movements, which implies the development of different capacities, understood as multifactorial preparation. The objective was to analyse the effects of training (aerobic and continuous) on the leg power, fatigue levels, speed, agility, body fat, muscle mass and bone mass of these players.
Methods
Seventy-two soccer players, male and under 17, from 4 teams participated. The teams performed 3 times a week training sessions of about 60–90 min each. Informed consent requests were given to their parents for authorisation to participate in this investigation. Data was collected in two different time points, about ten months apart. Specific tests were performed for each variable: the vertical jump with Bosco System for leg power, the T -Test for agility, the linear sprint test for speed and the RAST test for fatigue levels. A precision Tanita scale was used for the anthropometric tests such as body fat, muscle mass and bone mass. Statistical procedures were applied through the Wilcoxon test to compare the two time points of evaluation.
Results
Improvements were found between evaluations regarding the level of anthropometric and physical fitness variables.
Conclusions
The implemented training improved all the analysed variables with significant statistical values for leg power, speed, bone mass, muscle mass and fat mass.
... The use of physical fitness tests helps to examine the abilities of soccer players (strength, power, speed, agility, and aerobic and anaerobic capacity) and training programs to be better targeted. This is even more crucial given the complex nature of soccer (Svensson and Drust, 2005). The evaluations can be applied both in the laboratory context, which is usually more expensive and sensitive, and in the field, which is carried out by the trainers themselves at a lower cost (Drust et al., 2007). ...
... The evaluations of the physical capacities of the players were highly supported and used by the PTs to provide a more comprehensive depiction of player fatigue and whether recovery should be prioritized akin to previous research (Viru and Viru, 2001). This careful monitoring allows practitioners to demonstrate the evolution of the training process and information to make more accurate decisions about training prescription (Svensson and Drust, 2005). Such evaluations provide a logical framework for the use of performance tests that better understand the physiological demands of soccer (Drust et al., 2007). ...
... In this sense, and despite the difficulties that the participants may experience during the evaluation process (instrument, logistics, cultural, among others), they continue to be used to try to understand the player's performance capabilities. The practitioners tended to favor field-based tests that are more sport-specific, given their acyclic nature that is not amenable to time-series analysis and is incompatible with traditional exercise study models in laboratory conditions (Svensson and Drust, 2005). ...
Introduction
Physical trainers (PTs) are integral for managing load, reducing injury and optimizing performance in professional soccer. However, little is known about how this practitioners operate in the applied setting and how some of the nuances experienced influence practice.
Methods
This study explored the contemporary practices of PTs in professional soccer. Semi-structured interviews were undertaken with eight PTs from different professional teams in European and South American leagues. Interview questions were designed to extract information on the evaluation of physical abilities, monitoring and control of training and injury prevention. Subsequently, the interviews were video-recorded, transcribed, translated and analyzed using a content analysis approach.
Results
The results suggest that the evaluation of physical capacities is carried out by PTs at the beginning of the preseason. It also appears that it is attempted that this process of regular testing is applied during the competitive period, with most participants conducting partial physiological and physical evaluations at different stages throughout the competitive season. In relation to the monitoring and control of training, subjective feedback scales are used to estimate the internal load, and the use of GPS devices is common to quantify external loads. Injury prevention programmes were implemented by all participants and were generally in a multi-component format focused on preventing or optimizing physical capabilities.
Discussion
These insights can be used as a scientific reference point to inform applied practice in professional soccer, especially for practitioners that are inexperienced and aspiring to enhance how they operate in the field. Future investigations should explore the practices of PTs in detail and across a wider network in order to gain deeper and comprehensive insights into the applied soccer environment.
... After blood withdrawal the subjects had a personalized standard breakfast [28]. Approximately 2 hours later, after a 30-min warm-up, the athletes performed the Yo-Yo Intermittent Recovery Test Level 2 supervised by the same experienced investigator [29][30][31]. To minimize circadian rhythms and climate-related factors, the test was performed in similar environmental conditions (temperature: 18-20 • C; humidity: 50-60%) on an artificial turf, which is almost unaffected by weather conditions. ...
... The increase of about 20% in performance after training is in agreement with the values reported by other authors [29][30][31]34]. A significant decline in performance was observed in relation to age, regardless of biochemical markers. ...
... Therefore, the use of a different test of performance might show different results. However, it must be underlined that the Yo-Yo test is characterized by high-intensity exercise, with sudden accelerations and decelerations, which mimic the behavior of athletes in the field, and therefore, it is considered a reliable and valid measurement instrument of match-related performance in professional soccer athletes [29][30][31]. In the official sport seasons, the soccer players did not report the consumption of any spontaneous supplements or drugs, but omission or recall bias could not be excluded, and this situation could potentially influence the test performance results. ...
Vitamins, hormones, free radicals, and antioxidant substances significantly influence athletic performance. The aim of this study was to evaluate whether these biological mediators changed during the season and if this was associated with the rate of improvement in performance after training, assessed by means of a standardized test. Professional male soccer players took part in the study. Two evaluations were performed: the first in the pre-season period and the second at the mid-point of the official season, after about 6 months of intensive training and weekly matches. Blood levels of vitamins D, B12, and folic acid, testosterone and cortisol, free radicals, and antioxidant substances were measured. Two hours after breakfast, a Yo-Yo test was performed. The relationships between the biological mediators and the rate of improvement after training (i.e., the increase in meters run in the Yo-Yo test between the pre-season and mid-season periods) were evaluated by means of a linear mixed models analysis. Results: Eighty-two paired tests were performed. The athletes showed better performance after training, with an increase in the meters run of about 20%. No significant relationships between the vitamin and hormone values and the gain in the performance test were observed. Plasmatic levels of free radicals increased significantly, as did the blood antioxidant potential. An indirect relationship between oxidative stress and the improvement in performance was observed (free radicals β ± SE: = −0.33 ± 0.10; p-value = 0.001), with lower levels of oxidative stress being associated with higher levels of performance in the Yo-Yo test. Monitoring the measures of oxidative stress could be a useful additional tool for coaches in training and/or recovery programs tailored to each player.
... FIET is a high-intensity field test that involve aerobic and anaerobic metabolism (20). Freitas et al. (19) have found an increase in the PVFIET after 4 weeks of futsal training (exercises developing and strengthening power of lower and upper limb muscles) corresponding to the beginning of the competitive period characterized by a reduced total training volume (compared to the training period). ...
... Freitas et al. (19) have found an increase in the PVFIET after 4 weeks of futsal training (exercises developing and strengthening power of lower and upper limb muscles) corresponding to the beginning of the competitive period characterized by a reduced total training volume (compared to the training period). It is supposed that the great effect on FIET is due to the anaerobic system, as well as neuromuscular components (i.e., large number of changes of direction and short distance traveled during the match) (20). In young soccer players, Matos et al. (21) have observed increases in performance in the Yo-Yo intermittent endurance run test after a twelve-week field training combining strength and power. ...
Background: Futsal is a high-intensity team sport taxing both the aerobic and the anaerobic pathways. Thus, this sport requires the development of some specific physical capacities such as: Sprinting, jumping, agility and endurance. Objectives: Examine the effect of three months specific training on physical capacities (speed, explosive strength, agility and endurance) of Iraq futsal players. Methods: Twenty males’ professional futsal players (age: 19.73 ± 1.1 years, height: 172 ± 4.2 cm; body mass: 55.3 ± 8.9 kg) were divided into an experimental group (EG; n = 10) and a control group (CG; n = 10). Participants were selected from a first division team in Iraq. Before and after three months of specific training (at the pre-season phase), 5m and 15m sprint, counter movement jump (CMJ), change of direction [505 agility test (CODA)] and futsal intermittent endurance (FIET) tests were realized. During the three months, the CG continue their usual training and the EG used plyometric as well as technical and physical exercises. Results: For the sprint performance, although no-significant difference was reported between pre- and post-training for the 5 m sprint, the 15 m sprint performance was better at post- compared to pre-training (P < 0.05) for the EG. For jumping performance, CMJ was higher at post- compared to pre-training (P < 0.05) for the EG. Likewise, for agility and endurance, CODA performance and peak velocity during the FIET test were better at post- compared to pre-training (P < 0.05) for the EG. However, except a better performance for 15m sprint and peak velocity during the FIET test for the EG compared to CG at post-training (P < 0.05), no-significant differences were reported between pre- and post-training for the CG and between the two groups at pre- and post-training. Conclusions: In the light of these data, results have shown that improvement in physical capacities take into consideration the characteristics of futsal during training.
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
Background: The physiological adaptations of senior football players to intensive training remain a topic of interest in sports science. This study aims to investigate changes in insulin resistance, lipid profile, Comprehensive Physiological Metrics (CPM), and morphological traits in senior football players. Objectives:The objectives are to compare pre-test and post-test measurements of demographic data, CPM, morphological traits, insulin resistance (IR), and lipid profile among senior football players. Materials and Methods: Thirty senior football players participated in the study. Demographic data, CPM, morphological traits, IR markers (Insulin, FBG, HOMA-IR), and lipid profile markers (TC, TG, HDL-C, LDL-C) were assessed. Statistical significance was determined using p-values. Results: The study revealed significant improvements in several parameters. In current study, age and height remained non-significant. However, weight and BMI showed significant increases, and demonstrated significant improvements in Comprehensive Physiological Metrics (CPM), including calories burned (CB), total body water (TBW), body adiposity index (BAI), basal metabolic rate (BMR), average body fat percentage (ABF), and body fat weight percentage (BFW). Additionally, significant enhancements in morphological traits were observed, such as leg muscle circumference, hip circumference, waist circumference, and shoulder width. However, shoulder-to-waist ratio (SWR) and waist-to-height ratio (WHtR) showed mixed results, while waist-to-hip ratio (WHR) remained non-significant. Conclusion: Senior football players experienced significant improvements in insulin resistance, lipid profile, CPM, and various morphological traits following their training program. These findings suggest that regular football training can positively influence the health and fitness of senior individuals, contributing to their overall well-being.
Keywords: Senior football players, insulin resistance, lipid profile, Comprehensive Physiological Metrics (CPM), morphological traits, intensive training.
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
Background: The physiological adaptations of senior football players to intensive training remain a topic of interest in sports science. This study aims to investigate changes in insulin resistance, lipid profile, Comprehensive Physiological Metrics (CPM), and morphological traits in senior football players. Objectives:The objectives are to compare pre-test and post-test measurements of demographic data, CPM, morphological traits, insulin resistance (IR), and lipid profile among senior football players.
Materials and Methods: Thirty senior football players participated in the study. Demographic data, CPM, morphological traits, IR markers (Insulin, FBG, HOMA-IR), and lipid profile markers (TC, TG, HDL-C, LDL-C) were assessed. Statistical significance was determined using p-values.
Results: The study revealed significant improvements in several parameters. In current study, age and height remained non-significant. However, weight and BMI showed significant increases, and demonstrated significant improvements in Comprehensive Physiological Metrics (CPM), including calories burned (CB), total body water (TBW), body adiposity index (BAI), basal metabolic rate (BMR), average body fat percentage (ABF), and body fat weight percentage (BFW). Additionally, significant enhancements in morphological traits were observed, such as leg muscle circumference, hip circumference, waist circumference, and shoulder width. However, shoulder-to-waist ratio (SWR) and waist-to-height ratio (WHtR) showed mixed results, while waist-to-hip ratio (WHR) remained non-significant.
Conclusion: Senior football players experienced significant improvements in insulin resistance, lipid profile, CPM, and various morphological traits following their training program. These findings suggest that regular football training can positively influence the health and fitness of senior individuals, contributing to their overall well-being.
Keywords: Senior Football Players, Insulin Resistance, Lipid Profile, Comprehensive Physiological Metrics (CPM), Morphological Traits, Intensive Training
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
Background: The physiological adaptations of senior football players to intensive training remain a topic of interest in sports science. This study aims to investigate changes in insulin resistance, lipid profile, Comprehensive Physiological Metrics (CPM), and morphological traits in senior football players. Objectives:The objectives are to compare pre-test and post-test measurements of demographic data, CPM, morphological traits, insulin resistance (IR), and lipid profile among senior football players. Materials and Methods: Thirty senior football players participated in the study. Demographic data, CPM, morphological traits, IR markers (Insulin, FBG, HOMA-IR), and lipid profile markers (TC, TG, HDL-C, LDL-C) were assessed. Statistical significance was determined using p-values. Results: The study revealed significant improvements in several parameters. In current study, age and height remained non-significant. However, weight and BMI showed significant increases, and demonstrated significant improvements in Comprehensive Physiological Metrics (CPM), including calories burned (CB), total body water (TBW), body adiposity index (BAI), basal metabolic rate (BMR), average body fat percentage (ABF), and body fat weight percentage (BFW). Additionally, significant enhancements in morphological traits were observed, such as leg muscle circumference, hip circumference, waist circumference, and shoulder width. However, shoulder-to-waist ratio (SWR) and waist-to-height ratio (WHtR) showed mixed results, while waist-to-hip ratio (WHR) remained non-significant. Conclusion: Senior football players experienced significant improvements in insulin resistance, lipid profile, CPM, and various morphological traits following their training program. These findings suggest that regular football training can positively influence the health and fitness of senior individuals, contributing to their overall well-being.
Keywords: Senior football players, insulin resistance, lipid profile, Comprehensive Physiological Metrics (CPM), morphological traits, intensive training.
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa & Michaelides, 2021) [38] . Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson & Drust, 2007) [47] . ...
... Large significant associations between heart rate (HR) during the submaximal Yo-Yo Intermittent Recovery Test Level 1 (YYIR) and the distance covered in the maximal YYIR test are shown (especially in a trained population), suggesting that the YYIR submaximal test has a predictive validity for the corresponding maximal version [15]. Since elite football clubs often limit the number of occasions they maximally test players due to heavy fixture schedules [16], the submaximal YYIR test was proposed to monitor the players every eight weeks at match day + 2 or 3, after a recuperation training, in order to limit possible interference of previous exercise on these test results. This submaximal YYIR test consist of 2 × 20 m shuttle runs at increasing speed, interspersed with a 10-s period of active recovery (2 × 5m). ...
... The results of this study showed significantly higher %HRmax at 6 min during and at 1 and 2 min after the submaximal YYIR test. The non-significant higher %HRmax at 3 min during the YYIR test could be explained by the duration since 3 min is not enough to sufficiently speed-up the cardiovascular system [16,18]. In addition, formerly infected players showed significantly higher %HRmax (ranging from 6 to 11%) during and after the YYIR test compared to the non-infected players at the first testing after infection. ...
Objectives
To investigate possible persistent performance deficits after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in elite athletes.
Methods
A prospective cohort study in three Belgian professional male football teams was performed during the 2020 − 2021 season. Participants were submitted to strength, jump, and sprint tests and an aerobic performance test (the Yo-Yo Intermittent Recovery test (YYIR)). These tests were repeated at fixed time intervals throughout the season. Assessment of SARS-CoV-2 infection was performed by a polymerase chain reaction (PCR) test before each official game.
Results
Of the 84 included participants, 22 were infected with SARS-CoV-2 during follow-up. At the first testing after infection (52.0 ± 11.2 days after positive PCR testing) significantly higher percentages of maximal heart rate (%HRmax) were seen – within the isolated group of infected players- during (p = .006) and after the YYIR (2 min after, p = .013), compared to pre-infection data. This increase in %HRmax was resolved at the second YYIR testing after infection (127.6 ± 33.1 days after positive PCR testing). Additionally, when comparing the first test after infection in formerly infected to non-infected athletes, significantly higher %HRmax were found during (p < .001) and after the YYIR test (p < .001),No significant deficits were found for the jump, muscular strength or sprint tests.
Conclusion
Aerobic performance seems compromised even weeks after infection. Simultaneously, anaerobic performance seemed to be spared. Because of the potential detrimental effects on the immune system, caution might be advised with high-intensity exposure until aerobic performance is restored.
•
KEY MESSAGES
• Elite football players’ aerobic performance seems to be affected for weeks after they return to sports after a SARS-CoV-2 infection.
• Similarly, anaerobic performance tests showed no discernible changes between both before and after SARS-CoV-2 infections.
• Regular YYIR testing is recommended to monitor aerobic performance after SARS-CoV-2 infection.
... FIET is a high-intensity field test that involve aerobic and anaerobic metabolism (20). Freitas et al. (19) have found an increase in the PVFIET after 4 weeks of futsal training (exercises developing and strengthening power of lower and upper limb muscles) corresponding to the beginning of the competitive period characterized by a reduced total training volume (compared to the training period). ...
... Freitas et al. (19) have found an increase in the PVFIET after 4 weeks of futsal training (exercises developing and strengthening power of lower and upper limb muscles) corresponding to the beginning of the competitive period characterized by a reduced total training volume (compared to the training period). It is supposed that the great effect on FIET is due to the anaerobic system, as well as neuromuscular components (i.e., large number of changes of direction and short distance traveled during the match) (20). In young soccer players, Matos et al. (21) have observed increases in performance in the Yo-Yo intermittent endurance run test af-ter a twelve-week field training combining strength and power. ...
Background: Futsal is a high-intensity team sport taxing both the aerobic and the anaerobic pathways. Thus, this sport requires the development of some specific physical capacities such as: Sprinting, jumping, agility and endurance. Objectives: Examine the effect of three months specific training on physical capacities (speed, explosive strength, agility and endurance) of Iraq futsal players. Methods: Twenty males’ professional futsal players (age: 19.73 ± 1.1 years, height: 172 ± 4.2 cm; body mass: 55.3 ± 8.9 kg) were divided into an experimental group (EG; n = 10) and a control group (CG; n = 10). Participants were selected from a first division team in Iraq. Before and after three months of specific training (at the pre-season phase), 5m and 15m sprint, counter movement jump (CMJ), change of direction [505 agility test (CODA)] and futsal intermittent endurance (FIET) tests were realized. During the three months, the CG continue their usual training and the EG used plyometric as well as technical and physical exercises. Results: For the sprint performance, although no-significant difference was reported between pre- and post-training for the 5 m sprint, the 15 m sprint performance was better at post- compared to pre-training (P < 0.05) for the EG. For jumping performance, CMJ was higher at post- compared to pre-training (P < 0.05) for the EG. Likewise, for agility and endurance, CODA performance and peak velocity during the FIET test were better at post- compared to pre-training (P < 0.05) for the EG. However, except a better performance for 15m sprint and peak velocity during the FIET test for the EG compared to CG at post-training (P < 0.05), no-significant differences were reported between pre- and post-training for the CG and between the two groups at pre- and post-training. Conclusions: In the light of these data, results have shown that improvement in physical capacities take into consideration the characteristics of futsal during training.
... It is suggested that the greatest periods of temporal fatigue in match-play follow the most intense bouts of high-speed running (50,100); therefore, possessing a combination of both aerobic capacity and repeated sprint ability allows a player to perform greater successive high-intensity movement with short rest intervals (147). It is also evident that strength and power are essential characteristics for soccer performances (137). Previous research has linked relative strength and performance variables such as the aforementioned sprinting, COD, and jumping (51,71,145). ...
... The identification of testing protocols that incorporate soccerspecific physical capacities would allow female soccer players to accurately track fitness status, provide further information on their longitudinal improvements, and be used to program training. Although a large amount of research has now been conducted on testing in soccer players, these investigations have primarily focused on male players (68,137). Consequently, this forces female athletes and their practitioners to rely on the guides and results of male literature (44). ...
Beato, M, Datson, N, Anderson, L, Brownlee, T, Coates, A, and Hulton, A. Rationale and practical recommendations for testing protocols in female soccer: A narrative review. J Strength Cond Res XX(X): 000-000, 2023-The aim of this narrative review is to evaluate the presented literature on tests (aerobic, speed, changes of direction [COD], strength, power, jump, and anthropometry) of the varied components of female soccer and to draw attention to the most suitable protocols to allow practitioners to accurately track players' fitness status. The 2 most common field tests used to assess aerobic fitness are the Yo-Yo intermittent test (level 1 and level 2) and the 30-15 intermittent fitness test because of an ability to measure multiple players at once with a soccer-specific intermittent profile. The sprinting performance can be assessed on distances of <30 m; however, longer distances (e.g., 40 m) allow for achieving peak speed (flying sprint test), which can be assessed using global navigation satellite system. Changes-of-direction capacity has been found to be an important component of players testing and training programs, although there is no "gold standard" to assess COD or repeated sprint ability performance in female players. Lower-limb power can be assessed using jump tests that can use force platforms, jump mats, and optoelectronic devices, while maintaining a good reliability. Several in-direct tests are currently available for assessing anthropometry parameters, such as skinfold thickness, hydrodensitometry, and ultrasound. However, dual-energy x-ray absorptiometry is the most valid and reliable method for assessing body composition in team sport athletes, with the addition of bone health that is a key measure in female athletes. In conclusion, the evidence reported in this review will be able to aid practitioners, coaches, and researchers to decide which tests meet the requirements of their environment.
... Physiological testing in elite athletes requires reliable measurement tools, which can provide accurate and reproducible information about physical performance capacity (Svensson and Drust 2005;Bangsbo et al. 2006;Chirosa Ríos et al. 2022). Even minor improvements in mechanical muscle function (down to 1%) can make a significant difference for team sport players (Currell and Jeukendrup 2008), which means that precise test equipment and reproducible measurement protocols are required to assess the magnitude of training-induced adaptations in various elite athlete populations. ...
Purpose
This study aimed to assess the reliability of lower limb muscle function (knee extensor/flexor peak torque, rate of torque development (RTD), impulse, and countermovement jump (CMJ) performance) and sprint performance (acceleration capacity).
Methods
CMJ performance was evaluated on a force plate. MVIC, RTD and impulse variables were investigated using a portable isometric dynamometer and sprint performance was assessed with dual-beam photocells in elite female athletes.
Results
CMJ test variables maximal vertical jump height, peak and mean power, concentric work, and body center of mass displacement demonstrated good-to-excellent test–retest correlations between Test 1 and Test 2 (ICC ≥ 0.70, CWw-s = 3.4–11.0%). Peak MVIC torque for the knee extensors and flexors demonstrated excellent test–retest correlations (both ICC = 0.84) along with CVw-s values of 6.8 and 6.0%, respectively. Late-phase (0–100 ms, 0–200 ms) RTD for the knee flexors demonstrated excellent test–retest correlations (ICC = 0.89–0.91, CVw-s = 4.8–8.5%). Sprint times at 10- and 20-m demonstrated excellent test–retest reproducibility (ICC = 0.83 and ICC = 0.90, respectively) with CVw-s values of 1.9 and 1.5%. For 5-m sprint times, test–retest reproducibility was good (ICC = 0.71) with CVw-s of 2.8%. Sprint testing performed while dribbling a handball improved (p < 0.05) from test to retest at 5-, 10- and 20-m.
Conclusion
In conclusion, the force plate, the mobile isometric dynamometer, and dual-beam photocells provide reproducible tools for field-based testing of countermovement jump performance, knee extensor and flexor strength and sprint performance.
... Players must be able to engage in repetitive, intense, maximum or sub-maximal activities that demand a high level of oxidative energy throughout the entire game. Soccer players' level of competitiveness has an impact on their aerobic capacity, according to research findings [5]. ...
This study represents the inaugural investigation into the nutritional status of professional Moroccan football players. The aim of this research was to assess the energy and macronutrient consumption of elite football athletes during their preseason training phase while concurrently exploring possible associations between physical Fitness (PF) especially cardiorespiratory endurance (VO 2 max), macronutrient intake, and body composition. 27 footballers from a Moroccan professional league, 'Botola-Pro', in a consecutive 7 study during a microcycle of the preseason period. Dietary intake was assessed using self-reported methods, supplemented by 24-hour recalls, and body composition was measured using bioelectrical impedance (BI). The Yo-Yo IR test was employed to evaluate cardiorespiratory endurance. The football players had an energy intake significantly below their requirements. Average carbohydrate (CHO) intake fell below the recommendations set by the Union of European Football Associations (UEFA). However, protein intake was in line with recommendations (1.6 to 2.2 g/kg), and fat intake slightly exceeded the recommended values. The CHO intake was notably lower than recommended. A positive correlation was observed (p < 0.001 and r: 0,831) between CHO and VO 2 max. These results suggest that increasing carbohydrate consumption is associated with improved performance, especially within the range of 6 to 8 g/kg of body mass per day. Conversely, a negative correlation was identified (p < 0.01 and r:-0,514) between the body fat mass (BFM) and VO 2 max. In conclusion, the results of this study underscore aspects of nutrition that could be improved among professional football players to optimize their performance, longevity, and body composition. Therefore, a personalized care approach is highly recommended.
... The assessment of players' physical fitness through field and laboratory testing during the season, as well as after the transition period, is of great importance not only for the identification of strengths and weaknesses of the soccer players but also for the evaluation of the training programs and the changes in fitness status across the various phases of the season [12,13]. The seasonal variation in physical fitness has been investigated extensively in male elite soccer players, semi-professional players, and youths [14][15][16][17]. ...
Citation: Parpa, K.; Katanic, B.; Michaelides, M. Seasonal Variation and the Effect of the Transition Period on Physical Fitness Parameters in Youth Female Soccer Players. Sports 2024, 12, 84. https://doi. Abstract: This study examined seasonal variation and the effect of the transition period on physical fitness parameters in female youth soccer players. Twenty-four players (13-17 years old) were assessed through field and laboratory testing. They completed laboratory testing three times: (1) at the beginning of the season (post-preseason), (2) at the end of the regular season (postseason), and (3) following the transition period (preseason). Field testing was conducted post-preseason and postseason. Results indicated that weight and body fat significantly increased from post-preseason to postseason and following the transition period. A paired samples T-test revealed that the players performed significantly better in the vertical jump and 30 m sprint test (all p < 0.01) postseason compared to post-preseason. Also, it was indicated that torque production for the right quadriceps, left quadriceps, and right hamstring (all p < 0.01) was significantly reduced after the transition period by 10%, 11.8%, and 10.5%, respectively. Cardiorespiratory measurements demonstrated that performance on an incremental cardiopulmonary treadmill test, maximal oxygen consumption, velocity at the first ventilatory threshold, velocity at the second ventilatory threshold, and velocity at maximal oxygen consumption (all p < 0.01) were significantly reduced postseason and following the transition period. Based on the results, coaches and trainers should primarily focus on maintaining the aerobic capacity of the players during the season, as it has been indicated to be reduced from the beginning to the end of the competitive period (VO2max reduced by 3.3%). In addition, they should focus on maintaining lower body strength and aerobic capacity during the transition period.
... Employing a comprehensive fitness testing battery supports the development of well-rounded and physically robust soccer players (Svensson and Drust, 2005;Beato et al., 2023). Therefore, testing selection should be based on general and position-specific requirements of soccer (e.g., biomechanical and physiological aspects) (Turner et al., 2011), and 'testing for the sake of testing' should be avoided if it does not provide value to the training process. ...
This study provides insight into the current fitness testing practices in elite male soccer. One hundred and two practitioners from professional soccer leagues across 24 countries completed an online survey comprising 29 questions, with five sections: a) background information, b) testing selection, c) testing implementation, d) data analysis, and e) data reporting. Frequency analysis was used to evaluate the responses to fixed response questions and thematic analysis was used for open-ended questions to generate clear and distinct themes. Strength (85%) and aerobic capacity (82%) represent the most frequently assessed physical qualities. Scientific literature (80%) is the most influential factor in testing selection and practitioners conduct fitness testing less frequently than their perceived ideal frequency per season (3.6 ± 2 vs. 4.5 ± 2). Time and competitive schedule were the greatest barriers to fitness testing administration. Practitioners mostly used a ‘hybrid’ approach (45%) to fitness testing, blending ‘traditional’ (i.e., a day dedicated to testing) and ‘integrated’ (i.e., testing within regular training sessions) methods. Microsoft Excel is the most used software for data analysis (95%) and visualization (79%). An equal use of the combination of best and mean scores of multiple trials (44%) and the best score (42%) was reported. Comparing a player’s test performance with previous scores (89%) was the most common method for interpreting test results. However, only 38% considered measurement error. Digital displays and verbal feedback are the most common data reporting methods, with different data reporting processes for coaches and players. Practitioners can use data and findings from this study to inform their current testing practices and researchers to further identify areas for investigation, with the overarching aim of developing the field of fitness testing in elite male soccer.
... Numerous tests are used in soccer to measure linear speed, agility, aerobic capacity, power, strength, flexibility, and technical skills by incorporating various test batteries. [3,4] Apart from these tests, movement screening is also done to examine the quality of the movement. Movement quality refers to a person's capacity to execute a specific movement under control with appropriate or acceptable technique. ...
Introduction: Movement screening in soccer is used to assess injury risk and develop training plans to prevent sports injuries. Despite the
popularity of movement screening in soccer, their accuracy is uncertain. The systematic review aims to clarify the evidence surrounding the
association of different movement screening tools with injury prediction in soccer athletes.
Methods: The following databases will be searched: CENTRAL, MEDLINE, EMBASE, PEDro, SPORTDiscus, and CINAHL. Prospective cohort studies
involving athletes evaluated using movement screening tests (Functional Movement Screen™, Landing Error Scoring System, Tuck Jump Assessment, Y
Balance/Star Excursion Balance Test, Athletic Ability Assessment, and Soccer Injury Movement Screen). The primary outcome will be musculoskeletal injury.
Discussion: Many systematic reviews about using movement screening tests in sports have been published. However, the results of most
reviews are limited to the general usage of screening tests; there are very few reviews specifically on the soccer population. This systematic
review will investigate whether these tests can accurately predict injury, as some previous reviews are outdated. This study will also include
information on the sample size, recruitment period, methodological quality, and visibility of the eligible studies
... Coaches and practitioners should plan appropriate exposure to high-intensity actions during training sessions, with the aim of either developing or maintaining players' ability to perform intermittent effort as often as required during competition (Mohr et al., 2005;Svensson and Drust, 2005). The most common methods of training documented in professional soccer include high-intensity running training, ball-drills in the form of modified-sided games, and fieldbased drills that replicate the actions of match play (Buchheit and Laursen, 2013;Iacono et al., 2019;Kyprianou et al., 2019). ...
The aim of this study was to compare the running demands of transition games (TGs) and official matches, analysing their requirements according to the performance of each position. An observational design was used to examine the activity of 20 soccer players during official matches and TGs. GPS technology was used to monitor the total distance covered (DC), distance at speeds between 14–17.9 km·h−1, 18–21 km·h−1, and above 21 km·h−1, peak speed, accelerations and decelerations above 2.5 m·s−2, and Player Load for both activities. All players were assigned to groups: centre-backs (CBs), fullbacks (FBs), defensive midfielders (DMFs), offensive midfielders (OMFs), wide midfielders (WMFs) and strikers (Ss). TGs showed greater total DC, DC 14–17.9 km·h−1, DC 18–21 km·h−1, DC >21 km·h−1, accelerations and decelerations >2.5 m·s−2, and Player Load (p < 0.01). CBs, FBs and Ss showed more DC, DC 14–17.9 km·h−1, DC 18–21 km·h−1, DC >21 km·h−1, accelerations and decelerations >2.5 m·s−2 and Player Load in TGs (p < 0.01). In the midfielder positions, transition game players showed greater DC 18–21 km·h−1, DC >21 km·h−1, accelerations and decelerations >2.5 m·s−2 than in matches (p < 0.05). DMFs showed higher total DC (p < 0.05) and WMFs greater DC and DC 14–17.9 km·h−1 (p < 0.01) in these drills. During transition games CBs showed greater DC 14–17.9 km·h−1 than FBs, and greater DC than Ss (p < 0.05). FBs performed more decelerations >2.5 m·s−2 than DMFs and OMFs (p < 0.05). TGs produced a homogenized load in soccer players, independent of their position, which exceeded the external load of official matches.
... Running anaerobic sprint test, RAST; Counter movement jump, CMJ; YoYo test, etc.) 5,6,7 . In general these tests can give useful information about training status, rehabilitation process and maturation in base-categories 8,7,9 . Elevated physiological and psychological stress may represent a challenge for their growth and maturation 10 . ...
Anaerobic power tests are more common to be applied in intermittent sports, such as soccer. In general, these tests can give usefulinformation about training status, rehabilitation process and maturation in base-categories. The present study aimed to organize and evaluatethe findings about anaerobic power tests in base-category soccer players in different training seasons, through the validity and quality of thestudies. The review study organized selected studies through the research in three data bases and qualified each study using validated methods.After a screening a total of six studies were included for the evaluation. All the studies reveled acceptable qualification. Three of the six studiesdemonstrated improvement of anaerobic power in middle or ending of the season. Three studies showed no changes or decrease of anaerobicpower in the beginning of the season (pre-season). The conclusion was that base-categories (sub-15 and sub-17) appear to decrease the resultsin anaerobic power tests in the beginning of the pre-season.
... The soccer-specific field and laboratory tests above were used together to better understand the physiological demands and dynamic nature of soccer (Svensson & Drust, 2005). The participants were tested on natural grass wearing soccer shoes in field tests. ...
The purpose of this research was to compare the effects of maximal aerobic speed (MAS) training, small-sided games (SSG) training, and combined training (CT) on sprint, agility, lactate accumulation, repeated sprint, aerobic, and anaerobic endurance performances. Thirty under-16 male players participated in a 6-week randomized training study. Pre- and post-training all players completed a test battery involving body composition (body height and Dual Energy X-Ray Absorptiometry-DEXA), sprint tests (10 m, 20 m, and 30 m), Yo-Yo 1 test, Arrowhead agility test, blood lactate test, and Yo-Yo 2 test. A global positioning system (GPS) was used for monitoring. After the pre-tests, the players were randomly assigned to three groups as MAS, SSG, and CT. Mixed two-way ANOVA was used to compare the pre-test and post-test performance of the three groups. While the CT group had higher changes in body composition, repeated sprint, aerobic, and anaerobic endurance parameters compared to the MAS training group (p<.05); the SSG training group had similar changes as the CT group (p>.05). In conclusion, coaches and sports scientists are advised to choose CT for more efficient training, considering the differences between the MAS training and CT methods.
... Quantification of loads represents a fundamental factor in optimizing athletes' performance. This involves monitoring physiological and performance adaptation, both during training sessions and competitions (5). Load quantification uses two main indicators: internal load and external load (6). ...
Introduction
Padel's global growth highlights its technical complexity. The first publications focus on the physical aspects of padel, using methods that evaluate players’ endurance, strength, speed, and range of motion, while the quantification of load, using internal and external indicators, is crucial for performance optimization, whilst taking into account athletes’ profiles and levels. Therefore, the objective entailed analyzing the scientific literature about the conditional demands in competition within padel players from different levels.
Methods
Data was collected from various databases and after the selection process, the information was analyzed in mini review.
Results
The mini review shows that the conditional demands are categorized into internal and external load to try to obtain reference values that may define the demands of padel based on the competitive level and sex. Regarding the internal load, the heart rate (HR)% of the padel players from different levels is around 70%–80% of the HR Max. Regarding the external load, in femalés categories, a greater number of strokes are made per point which entails a longer duration in the points.
Conclusions
Padel research usually analyses physical demands using internal and external loading. HR% values (70%–80% HR Max) are consistent across studies. There is variation between variables such as strokes per point, and contextual factors affect the metrics. Further exploration is vital to obtain comprehensive benchmarks and understand the demands of this sport.
... Each time the athlete arrives at point "A", which is the starting point, the test distance is marked and recorded on the test paper. The test is terminated when the athlete reaches the exhaustion point or misses two consecutive signals (Bangsbo et al., 2008;Krustrup et al., 2003;Svensson and Drust, 2004;Castanga et al., 2006). ...
This study was conducted to determine the effect of four weeks of high intensity interval training on blood oxygen saturation, body composition and some performance parameters in young male football players. Pre-test-post-test control group experimental method was used in the study. Twelve experimental (age: 16,33,77 years; height: 171,50,6,23 cm; body weight: 58,33,5,19 kg) and 12 control (age: 16,50,52 years; height: 168,58,5,68 cm; body weight: 58,05,4,60 kg) male football players aged 15-17 years, who regularly exercise and have been playing football for at least 3 years participated in the study. In the study, the experimental group performed high intensity interval training 3 days a week in addition to football training for 4 weeks. The control group only performed routine football training. In the study, height and body weight, resting heart rate, systolic and diastolic blood pressure, blood oxygen saturation, body composition, 20 m sprint test, Illinois agility test and Yo-Yo interval running test were applied as pre and post tests. The normality level of the data was determined by Shapiro-Wilk test. Independent Sample T Test for independent groups and Paired Sample T Test for dependent groups were used to analyse the normally distributed data. According to the findings of the study, while statistical significance was determined in blood oxygen saturation, body composition, Illinois agility test and Yo-Yo interval running parameters of the experimental group (p<0.05), no significant difference was found in 20 m sprint test (p>0.05). According to the results of the study, it can be said that 4-week high intensity interval training has positive effects on blood oxygen saturation, body composition and performance parameters in young male football players.
... Antrenman ve müsabaka içerisinde ihtiyaçların doğru bir şekilde belirlenmesi spor bilimcilerine sporcuların daha sağlıklı gelişmesi için uygun antrenman yüklerini tespit etmesinde büyük avantaj sağlamaktadır (Castillo vd., 2017;. Yakın bir geçmişte bireysel veya belirli bir grubun performans parametrelerinin ölçümü yapılmaktaydı (Chamari vd., 2004;Svensson ve Drust 2005). Son teknolojik gelişmelerle antrenman ve müsabaka esnasında bütün takım oyuncularının zaman-hareket aktiviteleri takip edilebilmektedir (Carling vd., 2008). ...
Sistematik analiz futbolda branşında sporcuların performansları hakkında önemli bilgilerin elde edilmesini kolaylaştırmaktadır. Son teknoloji ile Gps sayesinde sporcunun müsabaka veya antrenman içerisinde gerçekleştirmiş olduğu koşular ve bu koşuların saha içerisinde hangi hızlarda gerçekleştirdiğini belirlemektedir. Bu çalışmanın amacı; profesyonel futbolcuların antrenmanlardaki dış yük takibinin incelenmesidir. Araştırmaya yaşları (26±3,97 yıl), boyları (173,36± 6,02 cm) vücut ağırlığı (74,36±3,16 kg) olan 19 erkek futbolcu katılmıştır. Çalışmanın istatistiksel analizi SPSS 24,0 paket programında Paired samples t testi kullanılarak yapılmıştır. Gerçekleştirilen istatistiksel analiz sonucunda; toplam mesafe (m), maksimum hız ve ortalama hız[km/sa] ölçümlerinin ön ve son test değerlerinin karşılaştırılması sonuçlarında anlamlı farklılık bulunmuştur (p
... These competitions typically involve a distance of about 6 500 meters, with about 670 meters of high-intensity running and about 300 meters of very high-intensity running [4,8]. Monitoring and assessment of players aerobic capacities can assist the coach to evaluate the effect of training practices and the overall training program, resulting in improved training prescription [9][10][11].VO2max measurement, which refers to the body's maximal capacity to use oxygen for maximal effort is the common aerobic measurement method of the aerobic capacity [12,13]. Indeed, A high VO2max is required to compete at the professional level in football. ...
This study aimed to develop reference curves of aerobic parameters of 20 m shuttle run test for Tunisian soccer players. The study was conducted in the 2022/2023 pre-season. The reference curves of the maximal aerobic speed (MAS) and the maximal oxygen uptake (VO2max) were developed according to the Lambda, Mu and Sigma (LMS) method, using data from 742 Tunisian premier league soccer players aged 11–18 years. Measured variables included: weight, height, body mass index and maximal heart rate (HRmax). HRmax was measured when the participants completed the maximal aerobic speed. VO2max was estimated using the 20 m shuttle run test protocol (speed increment every minute). Our results presented the smoothed percentiles (3rd, 10th, 25th, 50th, 75th, 90th and 97th) of MAS (km/h) and VO2max (ml/kg•min⁻¹) according to age. In addition, raw data showed that VO2 max was positively correlated with age (r = 0.333; P < 0.001), height (cm) (r = 0.279; P < 0.001), weight (kg) (r = 0.266; P < 0.001), practice period (years) (r = 0.324; P < 0.001) and BMI (kg/m²) (r = 0.10; P < 0.05). However, it was negatively correlated to HRmax (bpm) (r = −0.247; P < 0.001). Only the measurements within the age group [12–12.99] are significantly higher (p < 0.001; ES = 0.63) compared with the previous age group [11–11.99]. Finally, regarding prevalence, our findings showed that 15.5 % of the players in our sample had VO2max values above the 87.7th percentile cut-off, while only 0.3 % exceeded the 99.18th percentile. The development of normative curves could help coaches and physical trainers to more accurately detect weaknesses in the aerobic performance of their players in order to sustain high-intensity repetitive actions during a soccer match.
... An important part of the distance run during the match is the agility-based change of direction runs for the purpose of controlling the ball (Little & Williams, 2006). High-quality agility skills reduce the risk of injury, increase performance, and contribute to visual reaction in group games (Svensson & Drust, 2005). ...
The research aims to examine the relationship between cognitive performance, visual reaction time and agility parameters on football players. Twenty- five football players with an average age of 18-20 years (18.16 ± 0.68), who have been active for at least five years and who are in the Turkish U19 Super League participated in the study from the Turkish U19 Super League participated. Body composition (BODPOD), agility (Illinois test), visual reaction time (Witty Sem Microgate) and cognitive performance (Stroop Test) of the football players were measured. SPSS v23 was used in the analysis of the data and the significance level was taken as p
... This demands rigorous aerobic conditioning and cardiovascular fitness (Parpa and Michaelides, 2021). Longitudinal studies have shown a positive correlation between players with superior endurance levels and their ability to contribute consistently across the entire game duration (Svensson and Drust, 2007). ...
In the realm of senior football, training programs meticulously crafted to enhance these traits can wield a profound influence on players' performance. This study engaged 30 senior soccer players in a comprehensive physical fitness assessment, encompassing pre-test measurements taken on October 6, 2022, and post-test measurements on January 10, 2023. This comprehensive study explores the profound impact of sports training on morphological traits among senior football players. The investigation delves into the significant differences observed in weight and BMI, despite the consistency in age and height, shedding light on potential shifts in body composition influenced by the training program's effect on muscle mass and fat distribution. These remarkable findings underscore the program's capacity to meticulously shape the physical attributes of senior players, thereby warranting further in-depth exploration of its overall influence on both performance and health. The comparative analysis of morphological traits between the pre-test and post-test for senior football players yielded compelling results. Notably, leg muscle size exhibited a highly significant increase (p-value=0.000), transitioning from 33.57±2.49 cm in the pre-test to 36.07±2.42 cm in the post-test. This marked change reflects substantial lower-body muscle development attributable to the training program's efficacy. Similarly, hip circumference displayed a significant rise (p-value=0.001), progressing from 90.07±4.29 cm to 95.73±7.72 cm, suggesting intriguing alterations in the hip area, possibly associated with shifts in muscularity or adipose tissue distribution. Waist circumference also underwent a significant increase (p-value=0.020), ascending from 77.23±6.23 cm in the pre-test to 81.23±6.67 cm in the Post-test, implying transformations in abdominal muscularity or fat distribution. Furthermore, shoulder width showed a highly significant increase (p-value=0.0001), expanding from 103.87±3.29 cm to 111.77±5.61 cm, indicating noteworthy developments or changes in the upper body induced by the training program. While the shoulder-to-waist ratio (SWR) remained consistent with a non-significant p-value of 0.220, suggesting no substantial change in the ratio of shoulder width to waist circumference, the waist-to-height ratio (WHtR) displayed a significant increase (p-value=0.024) from 0.47±0.04 in the Pre-test to 0.49±0.04 in the Post-test. This transformation hints at alterations in body composition relative to height. Conversely, the waist-to-hip ratio (WHR) exhibited no significant difference between the pre-test and post-test measurements, with a non-significant p-value of 0.537, implying minimal changes in fat distribution around the waist and hip areas. These findings illuminate the potent effects of sports training on the morphological traits of senior football players, providing a foundation for tailored training strategies and enhanced player performance and health.
... Research has shown that soccer players' competitiveness is associated with their aerobic capacity [12]. Maximal oxygen consumption (VO2max) is considered the most reliable indicator of an athlete or team's success [13]. ...
Pre-competition training emphasizes the development of total physical fitness components and maintains aerobic and anaerobic capacity with improved techno-tactical skills. The primary objective of this investigation was to establish the efficacy of a pre-competition training program. There were a total of 24 (12 rugby and 12 Soccer) elite players randomly selected from the Ba and Lautoka regions (Fiji). The players had a mean age of 21.45±2.34 years, body mass of 84.62±6.62 kg, stature 183.35±3.24, and body mass index of 22.62±4.31 kg/m2. This study was conducted nine weeks before the main competition. The study involved a pre-and post-test design, wherein all participants underwent two rounds of testing. The pretest was conducted before the commencement of an eight-week pre-competition training program, while the post-test was administered after the program was completed. This pre-competition training program was scheduled five times per week for 45 minutes per day. The participant's performance was measured using the Beep test, Wingate anaerobic test, star excursion balance test, and visual motor coordination test. After eight weeks of the pre-competition training program, significant improvement has occurred for maximal aerobic capacity (t=-14.79, p=<0.001), anaerobic power (t=-12.22, p=<0.001), dynamic balance (t=-7.41, p=<0.001), and visual motor coordination (t=8.38, p=<0.001) in all the players. The study confirmed that the eight weeks of pre-competition training programs containing aerobic and anaerobic workouts enhanced the performance of the Beep test, Wingate anaerobic test, star excursion, and visual motor coordination test.
... and students from either the Department of Sport and Exercise Science of the University of Salzburg, or the Elite Sport Centre Austria on an indoor surface. The time of the day, the sequence of the tests, starting with non-fatiguing exercises, and the measurement systems (30)(31)(32) were kept identical throughout the years. ...
Current trends in attacking strategies and increases in external workload have led to a need for fast and well-conditioned athletes in modern soccer. More recently, progressions in speed, coordination, power and endurance were found over a decade in elite Austrian youth players. However, possible confounders such as relative age, maturation, learning effects, and academy philosophy may have influenced these changes. The present study aimed to determine the decade effect on fitness under statistical control of players' exact age, height, body mass, test location as well as total number of pretests and time interval between test and pretest. Players annually completed a battery of anthropometric, general and soccer-specific fitness tests. MANCOVA was calculated to identify the overall impacts of the covariates on fitness. To balance the covariates of initially 2,530 “former” (2002 to 2005) and 2,611 “recent” (2012 to 2015) players, 1:1 nearest neighbor propensity score (PS) matching was used, resulting in 587 U13, 573 U14, 475 U15, 325 U16, 262 U17, and 129 U18 matched pairs. The decade effect on fitness was assessed by independent t -tests and Cohen's d separately at each age group. Superior performances of recent players were found for linear sprint across all age categories ( d = 0.154–0.476) as well as for agility ( d = 0.125–0.340) and change-of-direction speed ( d = 0.172–0.466) in U15 to U18. Reaction speed increased in U13 ( d = 0.288) and U15 ( d = 0.310). Flexibility reduced over the decade in all age categories ( d = −0.151 to −0.589) and upper-limb power decreased ( d = −0.278 to −0.347) in U13 and U14. Balancing the covariate distribution via PS matching generally confirmed previous findings, with fitness decade effects reflecting the athletic needs for modern soccer. Since fitness performance changed over time, reference values should be periodically updated. Coaches favor both physical and cognitive fast players nowadays. Thus, training should target all aspects of speed, without disregarding flexibility, upper-limb power and other preventive strategies that keep the players on the pitch.
... In more recent research also showed that successful performances in a team sport, such as soccer, requires the ability to change direction, as well as decision-making skills (Lesinski et al., 2017;Loturco et al., 2017). Furthermore, it has been suggested that agility is one of the key performance indicators that should be part of standardized physiological tests and training goals for soccer players (Svensson and Drust, 2005). However, the most effective training methods used to improve performance incorporate conditions similar to a real soccer game (Aguiar et al., 2012). ...
Despite the extensive use of SSGs training in soccer, our knowledge about their effectiveness as a training tool for developing physical, technical and tactical skills in soccer players is not complete (Hill-Haas et al., 2011). The aim of the present study is to examine the effects of a 4-week SSGs training intervention on the agility and sprinting ability of professional soccer players in season. Twenty-four male professional soccer players (3 Central Defender, 4 Full Backs,4 Central Midfielders, 4 Attack Midfielders, 6 Wingers, 3 Strikers) with age (26±3,45y), height (1,81± 3,78m), body weight (75,23±5,62 kg), BMI (24,17 ±1,59kg/m 2) of second professional Greek league participated in this study. They were randomly assigned to small side games training group (SSG, n=12) or a control group (CG, n=12). This study was conducted in season, when participants attended soccer training sessions five times per week and played competitive matches at least once a week. In order to examine the changes in agility and sprinting ability after the 4-week meso-cycle periodized small side games training, all players were tested two times, pre and post of the intervention. Body mass was measured the same days of testing but in the morning before breakfast. All the test sessions were carried out on a grass soccer field after a typical 15min soccer warm up. The order of the tests was 30m linear sprint and illinoise agility test. Statistical analysis was conducted using SPSS 18.0 for Windows and the significance level was set at P≤0.05. Data were tested with two-way analysis (2x2 ANOVA) with repeated measure (groups x measurement). In variables that were significant interaction we continue with paired t test. Results showed that there was statistically significant interaction in Agility with p=0,000, t= 4,458 and there was no statistically significant interaction in 30m Sprint with p=0,770, t= 0,298, in Bodyweight with p=0,245, t= 0,809 and in BMI with p=0,994, t= 0,809.
... Hopker et al. [30] also demonstrate that field-based testing is not as reliable as laboratory testing, therefore, it should not be expected that a field-based test has equal test-retest reliability compared to laboratory tests. A trade-off must be made between reliability and practicality or specificity of testing [31]. Therefore, it could be suggested that SoA has adequate test-retest reliability as the Scatt MX-02 system can be used at home ranges, making it practical and specific to competition environments, more so than controlled laboratory settings. ...
The validity of a commonly used optoelectronic training system was examined by identifying the variables that predicted shot score, investigating their ability to discriminate standard, and assessing the predictive variables’ test–retest error. A repeated-measures approach assessed test–retest error, a cross-sectional approach compared standards of shooters and an observational approach examined predictors of shot score. 21 elite and 8 national-standard athletes participated. Multiple linear regression, independent t tests, typical error and coefficient of variation assessed predictors of shot score, discrimination between standards and test–retest error respectively. Stability of aiming predicted 84.2% of the variance in shot score. Six Scatt Expert variables, 10a0, 10a5, 10.0, 10.5, Speed in the last 250 mm, and stability of aiming, discriminated standard (P < 0.05). Test–retest error ranged from a coefficient of variance of 0.72% for 10a0 to 30.69% for Accuracy of Aiming. Stability of aiming had a typical error of 0.55 mm and a coefficient of variance of 13.93%. Results suggest that this optoelectronic training system possesses construct validity if stability of aiming is used as the outcome measure.
... Es una indicación del límite funcional del sistema de transporte de oxígeno en los individuos. Es decir, brinda la ayuda para determinar las posibilidades de una persona ante esfuerzos prolongados (Svensson & Drust, 2005). ...
El entrenamiento interválico se enfoca en desarrollar y mejorar el rendimiento del futbolista en lo referente a la habilidad para realizar esfuerzos máximos, pues ayuda a potenciar la capacidad aeróbica y lograr técnicas y tácticas adecuadas en este deporte. El objetivo de esta esta investigación fue ejecutar un programa de entrenamiento interválico para mejorar la resistencia aeróbica en futbolistas de las categorías formativas del Orense S.C. Esta investigación es de tipo cuasi experimental con la aplicación de un pre y post test de alcance explicativo, enfoque cuantitativo y corte longitudinal. Se aplicó la técnica de medición e instrumento fue el test para el proceso de recolección de datos. La población del estudio estuvo conformada por 30 jugadores de fútbol. Los resultados muestran que después de la aplicación de los test, los futbolistas obtuvieron resultados óptimos y mejoraron su velocidad y resistencia. Se concluye que es necesario enfatizar en el desarrollo del entrenamiento interválico, para lo cual se propone un plan de entrenamiento para la obtención de resultados positivos.
... Non-exhaustive testing is therefore preferable to assess athletes' training status when functional capacity is limited during rehabilitation from injury or when frequent testing is required (Bangsbo et al., 2008). As elite football clubs often limit the number of occasions they evaluate players due to heavy fixture schedules, submaximal tests have been proposed as an alternative to maximal testing (Svensson & Drust, 2005). Observations in elite football players revealed that mean heart rate (HR mean ) obtained after 6 min of the submaximal versions of the Yo-Yo intermittent recovery level 1 (Yo-Yo IR1) or Yo-Yo intermittent endurance level 2 (Yo-Yo IE2) tests were correlated to performance in various maximal tests and highly reproducible in professional football players (Bangsbo et al., 2008;Bradley et al., 2011;Krustrup et al., 2003). ...
... The blood lactate level is a biochemical marker of muscle fatigue. According to Durst et al. [65], the blood lactate concentration and heart rate are the best biomarkers of the internal load during physical effort. The lactate levels were similar in both groups in our study, and no association was noted between malocclusion and blood lactate levels. ...
Oral pathologies can cause athletic underperformance. The aim of this study was to determine the effect of malocclusion on maximal aerobic capacity in young athletes with the same anthropometric data, diet, training mode, and intensity from the same athletics training center. Sub-elite track and field athletes (middle-distance runners) with malocclusion (experimental group (EG); n = 37; 21 girls; age: 15.1 ± 1.5 years) and without malocclusion (control group (CG); n = 13; 5 girls; age: 14.7 ± 1.9 years) volunteered to participate in this study. Participants received an oral diagnosis to examine malocclusion, which was defined as an overlapping of teeth that resulted in impaired contact between the teeth of the mandible and the teeth of the upper jaw. Maximal aerobic capacity was assessed using the VAMEVAL test (calculated MAS and estimated VO2max). The test consisted of baseline values that included the following parameters: maximum aerobic speed (MAS), maximal oxygen uptake (VO2max), heart rate frequency, systolic (SAP) and diastolic arterial pressure (DAP), blood lactate concentration (LBP), and post-exercise blood lactate assessment (LAP) after the performance of the VAMEVAL test. There were no statistically significant differences between the two study groups related to either anthropometric data (age: EG = 15.1 ± 1.5 vs. CC = 14.7 ± 1.9 years (p = 0.46); BMI: EG = 19.25 ± 1.9 vs. CC = 19.42 ± 1.7 kg/m2 (p = 0.76)) or for the following physical fitness parameters and biomarkers: MAS: EG = 15.5 (14.5–16.5) vs. CG = 15.5 (15–17) km/h (p = 0.47); VO2max: EG = 54.2 (52.5–58.6) vs. CG = 54.2 (53.4–59.5) mL/kg/min (p = 0.62) (IQR (Q1–Q3)); heart rate before the physical test: EG = 77.1 ± 9.9 vs. CG = 74.3 ± 14.0 bpm (p = 0.43); SAP: EG = 106.6 ± 13.4 vs. CG = 106.2 ± 14.8 mmHg (p = 0.91); DAP: EG = 66.7 ± 9.1 vs. CG = 63.9 ± 10.2 mmHg (p = 0.36); LBP: EG = 1.5 ± 0.4 vs. CG = 1.3 ± 0.4 mmol/L (p = 0.12); and LAP: EG = 4.5 ± 2.36 vs. CG = 4.06 ± 3.04 mmol/L (p = 0.60). Our study suggests that dental malocclusion does not impede maximal aerobic capacity and the athletic performance of young track and field athletes.
... VO2max in soccer players has been correlated with increased work on the field during a match; therefore we believe that this data can be used as a benchmark for training and improvement in physical fitness. It appears that the VO2max level in well-trained players is dependent on the level of competition [25]. ...
... The combined load of high-intensity interval training that followed the strength with resistance training may induce muscle damage and inflammation lasting for several days [17,27]. Thus, a period of reduced training may be necessary for the benefits of this training to emerge [28] in order to prevent possible chronic fatigue, as may be the case for the HIIT Train group [29]. On the other hand, circuit and plyometric training against the players' body weight resulted in a slight, although non-significant, improvement of CMJ height during this 4-week pre-season period. ...
The aim of the present study was to evaluate two different intervention programs applied during a 4-week pre-season period. Twenty-nine players participated in this study and were divided into two groups. One group (Ball Train , n = 12, age: 17.8 ± 0.4 years, body mass: 73.9 ± 7.6 kg, height: 178 ± 0.1 cm, body fat: 9.6 ± 5.3%) performed a higher percentage of aerobic training with ball and strength training using plyometrics and exercises with body weight. The other group (HIIT Train , n = 17, age: 17.8 ± 0.7 years, body mass: 73.3 ± 5.0 kg, height: 179 ± 0.1 cm, body fat: 8.0 ± 2.3%) trained with high-intensity interval training (HIIT) without the ball and performed resistance training with weights in the same session. Both groups trained for strength (two times/week) and performed aerobic-anaerobic fitness without the ball, passing games, and tactical and small-sided games. Lower limb power (CMJ) and aerobic fitness (Yo-Yo intermittent recovery test level 1-IR1) were evaluated before and after the four-week training program. Yo-Yo IR1 performance was improved in both groups, but the improvement was greater for the HIIT Train than Ball Train group (468 ± 180 vs. 183 ± 177 m, p = 0.07). CMJ showed a non-significant improvement in the Ball Train group (5.8 ± 8.8%, p = 0.16), but it decreased by 8.1 ± 9% (p = 0.001), in the HIIT Train group. In conclusion, we have shown that a short pre-season period of training results in improvements in aerobic fitness in both groups, with high-intensity interval training showing superior adaptations than training with the ball. However, CMJ performance was reduced in this group, possibly suggesting higher fatigue levels and overload, and/or showing the effects of concurrent HIIT Train and strength training in soccer.
... Kinerja yang sukses dalam olahraga tim, seperti sepak bola, membutuhkan kemampuan mengubah arah, tetapi juga keterampilan persepsi dan pengambilan keputusan yang dikembangkan dengan baik yang dibuktikan dengan kinerja motorik antisipatif yang unggul (Bate, 1996;Gabbett et al., 2008;Gabbett & Benton, 2009;Lesinski et al., 2017;Loturco et al., 2017). Dengan demikian, telah disarankan bahwa kelincahan adalah salah satu indikator kinerja utama dan merupakan komponen yang berhubungan dengan keterampilan kebugaran yang harus menjadi bagian dari pengujian fisiologis standar untuk pemain sepak bola (Svensson & Drust, 2005). Oleh karena itu, kelincahan seringkali dijadikan sebagai pengkondisian pada atlet sepak bola yang sering dipertimbangkan dalam meningkatkan performa atlet. ...
Pendahuluan : Pliometrik merupakan bentuk latihan strength and conditioning yang sangat populer dan telah dipelajari secara ekstensif selama beberapa dekade terakhir. Latihan pliometrik dapat meningkatkan kelincahan, komponen penting dalam permainan sepak bola. Namun, efek latihan pliometrik terhadap peningkatan kelincahan masih menjadi perdebatan. Tujuan: untuk membuktikan efek latihan pliometrik terhadap peningkatan kelincahan pada atlet dengan riwayat cedera kronik ankle sprain. Metode: Penelitian ini adalah pre-eksperimen dengan rancangan penelitian One Groups Pretest-Posttest Design. Sebanyak 12 remaja laki-laki usia 16 – 19 tahun, indeks masa tubuh (IMT) 18 – 23 kg/m2, tekanan darah normal, denyut jantung istirahat normal dan memiliki riwayat cedera ankle sprain melalui hasil pemeriksaan Chronic Ankle Instability Tools (CAIT), Foot and Ankle Ability Measure (FAAM), Sports Subscale, Single Hop Test and Multiple Hop Test) dengan hasil positif ikut berkontribusi dalam penelitian. Intervensi latihan pliometrik (Mini Hurdle, Z-Drill dan Y-Shaped) dilakukan 4 kali/minggu selama 4 minggu dan dilakukan pada pukul 07.00–09.00 WIB. Pengukuran kelincahan dilakukan sebelum dan setelah 4 minggu latihan pliometrik dengan menggunakan T-Test (satuan detik). Hasil: Hasil penelitian menunjukkan terdapat peningkatan signifikan kecepatan kelincahan antara pretest vs. posttest (p ? 0,001) Kesimpulan: Berdasarkan hasil penelitian disimpulkan latihan pliometrik yang dilakukan 4x/minggu selama 4 minggu efektif dalam meningkatkan kecepatan kelincahan
... Comparisons between groups were facilitated by using traditional field fitness tests that have previously been reported to be relevant to soccer [14,28]. All participants were evaluated at two time-points during the season: ...
... Coordinative capacity agility is one of the key performance indicators in soccer. It is a fitness-skill-related component that should be a part of standard physiological testing for soccer players [7]. Soccer match performance indicates that the game is characterized by fast movements that become prominent in short and long sprints, explosive reactions (such as jumping), and quick changes in direction [8]. ...
Agility is a fitness-skill-related component that should be a part of the standard physiological testing for soccer players and one of the key performance indicators in soccer. The present study aimed to assess the reliability of the CRAST as a research tool in the study of soccer skills. Twenty-one university soccer players (chronological age: 19.3 ± 1.4 years; body mass: 69.6 ± 8.2 kg; stature: 173.5 ± 6.5 cm; federated training experience: 9.7 ± 3.6 years) volunteered for the testing protocol. The CRAST requires players to complete random courses six times as quickly as possible. In addition, the CRAST requires players to control and dribble the markers (four different colors: green, yellow, blue, and red). The soccer players completed three trials, each separated by one week. The first trial accounted for familiarization; the second and third were considered for analysis. The correlation for overall performance was very strong. The reliability of the CRAST was slightly better for total time than that for the penalty score (0.95 vs. 0.93). The TEM and the associated CV range of 7.04%–7.54% were for the penalty score and the total time, respectively. For both measurements, the ICC values also represent excellent reliability, as both values were over 0.900. The CRAST is a reliable protocol for assessing agility in soccer players.
... Савремена фудбалска игра захтева покрете и активности који се одликују изразито брзим, снажним и експлозивним способностима. Анализирањем такмичарске активности фудбалера, може се закључити да у фудбалу преовлађује интермитентна структура кретања са великим бројем акција са и без лопте, које су високоинтензивног карактера и између њих се јављају периоди ниско-интензивних активности (Svensson and Drust, 2005). ...
У савременом свету, спортске повреде заузимају високо место у хијерархији учесталости повреда. Услед излагања организма великим напорима током бављења спортом, могу настати бројне и разноврсне повреде које су најчешће последица понављаних микротраума, али могу бити и акутне, услед наглог деловања одређене силе. Повреде могу бити специфичне и неспецифичне. Циљ овог истраживања је да се прикупе и анализирају истраживања објављена у последњих десетак година на тему спортских повреда у гимнастици. Прикупљено је укупно шест истраживања која су одговарала свим постављеним критеријумима и која су била подвргнута даљој анализи.
... Савремена фудбалска игра захтева покрете и активности који се одликују изразито брзим, снажним и експлозивним способностима. Анализирањем такмичарске активности фудбалера, може се закључити да у фудбалу преовлађује интермитентна структура кретања са великим бројем акција са и без лопте, које су високоинтензивног карактера и између њих се јављају периоди ниско-интензивних активности (Svensson and Drust, 2005). ...
Овим истраживања се је желело утврди заступљеност деформитета ногу код деце предшколског узраста у Републици Србији. Приликом сакупљања досадашњих истраживања претраживане су следеће базе података: KOBSON, SCIndeks, Google Scholar, Google. Претраживанa су истраживања у последњој декади односно у периоду од 2005. до 2015. године. Да би се истраживање прихватило за коначну анализу, било је потребно задовољити критеријуме: да постоје испитаници којима је вршена процена деформитета ногу и да су испитаници предшколског узраста у Републици Србији. Бројна истраживања (111) су искључени на основу унапред прецизираних критеријума, осталих 7 истраживања су испунила постављене критеријуме. У истраживањима које је обухватило ово истраживање измерено је 3205 детета. Деформитет ногу дијагностикован је код 773 детета, односно 24,118%. Увидом метода којим се процењивало постурално стање ногу, може се предложити метод Наполеона Воланског и соматоскопска метода. Резултати овог истраживања указују да је засупљеност неправилног постуралног статуса ногу веома велики односно да свако четврто дете предшколског узраста у Србији има нарушен постурални статус ногу.
Introdução: A assimetria de força em jogadores de futebol pode ser decorrente de demandas unilaterais ao longo de anos de treinamento e pode estar relacionada a maior risco de lesão e comprometimento do desempenho. No entanto, os valores de corte usados para classificar a assimetria podem ser diferentes entre testes ou resultados. Objetivo: O objetivo foi comparar a distribuição de jogadores de futebol classificados como simétricos ou assimétricos com base no valor de corte arbitrário de 15% e no método Upper Limit Value para impulso e pico de força. Métodos: 184 jogadores profissionais de futebol brasileiro realizaram o teste de salto com contramovimento em duas plataformas de força. O índice de simetria foi utilizado para quantificar a assimetria do pico de força e impulso. O valor de corte de 15% foi então comparado com o valor de corte estimado a partir do Valor Limite Superior. O teste χ² de McNemar foi utilizado para verificar a concordância diagnóstica. Resultados: O valor limite superior para força de pico e assimetrias de impulso foi de 10,86% e 25,31%, respectivamente. O teste χ² de McNemar confirmou a hipótese de que a classificação dos atletas seria estatisticamente diferente entre os valores de corte. Conclusão: Concluiu-se que os valores de corte baseados no Valor Limite Superior para impulso e força de pico foram diferentes dos valores de corte de 15%. Os treinadores devem estar atentos a esta diferença na classificação escolhendo o valor de corte mais adequado à sua equipe. Nível de Evidência II; Estudos Diagnósticos–Investigação de um Exame para Diagnóstico.
Introduction: Strength asymmetry in soccer players may arise from unilateral demands along years of training and may be related to higher injury risk and performance impairment. However, cut-off values used to classify asymmetry can be different among tests or outcomes. Objective: The aim was to compare the distribution of soccer players classified as symmetric or asymmetric based on the arbitrary cut-off value of 15% and the Upper Limit Value method for impulse and peak force. Methods: 184 professional Brazilian soccer players did the countermovement jump test on two force plates. The symmetry index was used to quantify the asymmetry of peak force and impulse. Then, cut-off value of 15% was compared with the cut-off value estimated from the Upper Limit Value. McNemar χ² test was used to verify the concordance of diagnostic. Results: Upper Limit Value for peak force and impulse asymmetries were 10.86% and 25.31%, respectively. McNemar χ² test confirmed the hypothesis, that the classification of athletes would be statistically different between cut-off values. Conclusions: We concluded that cut-off values based on Upper Limit Value for impulse and peak force were different from the 15% cut-off values. Coaches should be aware of this different classification choosing the cut-off value that best fits their team. Level of Evidence II; Diagnostic Studies–Investigation of a Diagnostic Test.
This study investigated the effectiveness of supplementing regular preseason soccer training with a supramaximal intermittent shuttle-run training (ISRT) model prescribed from Carminatti's Test peak speed (PST-CAR) in aerobic performance-related indices and sprinting speed in male junior soccer players. Twenty-three national-level soccer players (mean ± SD; age 18.07 ± 0.9 y, body height 1.76 ± 0.65 m, body mass 71.9 ± 8.7 kg) were assigned to either an experimental group (EG; n = 13) performing ISRT + soccer training or a control group (CG; n = 10) that followed regular preseason soccer training alone. The following tests were applied before and after the eight-week training intervention: (i) incremental treadmill tests (VO2max and lactate minimum speed-LMS); (ii) linear 30-m sprint test and Carminatti's Test (PST-CAR). Results indicated larger gains for the EG in LMS (Δ = 9.53% vs. 2.82%) and PST-CAR (Δ = 5.50% vs. 2.10%) than in the CG. Furthermore, changes in VO2max produced higher effect size (d) values for the EG (Δ = 6.67%; d = 0.59) than the CG (Δ = 1.88%; d = 0.18). Both groups improved (p = 0.002) their flying 20-m sprint speed (EG: Δ = 1.01%; CG: Δ = 1.56%). However, small decreases were observed for 10-m sprint speed in the CG (Δ = −2.19%; d = −0.44), while only trivial changes were noticed for the EG (Δ = −0.50%; d = −0.16). Our data support that additional supramaximal ISRT is an effective training stimulus to enhance aerobic performance-related indices and promote small improvements in maximal running speed without impairing the soccer players' acceleration capacity. This study also shows that PST-CAR can be useful for individualizing running intensity in supramaximal ISRT modes.
Background: The popularity of Tunisian tennis is on the rise, due to emerging players gaining global recognition, leading to growth and evolution in the sport. In order to optimize training and performance, coaches need valuable information on physical fitness and player profiling. Objectives: The study aimed to investigate the physical profile of Tunisian tennis players in different age groups ranging from 7 to 17 years. Methods: Ten players from the same team were assigned to six age groups (U9-U18); U9 (7.89 ± 0.32), U10 (8.88 ± 0.34), U11 (9.78 ± 0.43), U12 (10.81 ± 0.4), U14 (12.3 ± 0.73), and U18 (14.69 ± 0.95) and were assessed for standing long jump (SLJ), countermovement jump, medicine ball throw (MBT), various sprint distances, agility drills, 20m Shuttle run (20mSRT), and Sit and reach tests. Results: The results showed that U14 and U18 age groups demonstrated better performance than U9 and U10 in jump tests, while U18 and U14 outperformed only U9 in the MBT test. U11 showed better performance than U9 and U10 in sprints, sideways shuffle, and spider drill tests. U9 and U10 had lower performance than U12 in SLJ, 20m sprint, sideways shuffle, and zigzag tests, and U11 outperformed U9 in the SLJ test. U18 and U14 had higher VO2max than U10 and U11, while U12 was higher than U11 only. No difference in flexibility was reported. The centile estimates of physical performances among Tunisian tennis players provide a means to compare individual player test results with the standard performance levels of the group. Conclusions: In conclusion, this study found that 11–17-year-old players exhibited greater physical performance than 7–10-year-old players. However, no age effect was found for flexibility.
Soccer is also known as a complex sport as it involves physical, physiological and technical demand to be fit. Many professional soccer clubs actively investigate the factor to achieve high performance in soccer. Thus, the aim of this study was to establish the validity, reliability and development of soccer-specific battery tests. A total of 223 young male soccer players from several soccer positions between 13 and 17 years old participated in this study. However, 59 young male soccer players chosen randomly were performed in reliability test and accomplished 2 trials tests (run with ball, long passing, short passing, shooting to the right top corner (dead ball), shooting to the left top corner (dead ball), shooting from a pass (foot), heading mid-post and side-post). The data were tested using ANOVA to distinguish the conceivable systematic bias between 2 attempts of trial in each test, and also discriminant analysis (DA) was used to discriminate between elite and non-elite players from selected battery tests. The evaluated test revealed high intraclass correlation coefficients on run with ball (intraclass correlation coefficient > 0.90), meanwhile for other tests only at moderate levels (intraclass correlation coefficients, > 40) and small within-individual variation (coefficients variation, > 0.16%). DA successfully discriminates between elite and non-elite soccer players with seven significant parameters with elite tend to have greater aerobic functional capacity, more skilful and matured compared to non-elite (p < 0.05). Establishment of specific skill-related performance with moderate to high validity and reliability will ensure the distinction between elite and non-elite soccer players.KeywordsIntraclass correlation coefficientCoefficient variationReliability testSoccer
The aim of this study was to investigate maximum aerobic power (VO2 max) and anaerobic threshold (AT) as determinants of training status among professional soccer players. Twelve professional 1st team British male soccer players (age: 26.2 ± 3.3 years, height: 1.77 ± 0.05 m, body mass: 79.3 ± 9.4 kg) agreed to participate in the study and provided informed consent. All subjects completed a combined test of anaerobic threshold (AT) and maximum aerobic power on two occasions: Test 1) following 5 weeks of low level activity at the end of the off-season and Test 2) immediately following conclusion of the competitive season. AT was assessed as both lactate threshold (LT) and ventilatory threshold (VT). There was no change in VO2 max between Test 1 and Test 2 (63.3 ± 5.8 ml·kg(-1)·min(-1) vs. 62.1 ± 4.9 ml·kg(-1)·min(-1) respectively), however, the duration of exercise tolerance (ET) at VO2 max was significantly extended from Test 1 to Test 2 (204 ± 54 vs. 228 ± 68 s respectively) (P<0.01). LT oxygen consumption was significantly improved in Test 2 versus Test 1 (P<0.01) VT was also improved (P<0.05). There was no significant difference in VO2 (ml·kg(-1)·min(-1)) corresponding to LT and VT. The results of this study show that VO2 max is a less sensitive indicator to changes in training status in professional soccer players than either LT or VT.
Purpose:
To compare the maximum oxygen uptake V0(2max) of elite endurance athletes and to explain why the body mass exponent, necessary to render V0(2max) independent of body mass, appears to be greater than 0.67.
Methods:
Study 1: V0(2max) of 174 international sportsmen and women was assessed. Athletes were recruited from seven sports (middle- and long-distance runners, heavyweight and lightweight rowers, triathletes, and squash and badminton players). Study 2: calf and thigh leg muscle masses were estimated in 106 male and 30 female athletes from 11 sports. Differences in V0(2max) and leg muscle masses between "sports" and "sex" were analyzed independent of body mass by using allometric log-linear ANCOVA.
Results:
Heavyweight rowers had the greatest V0(2max) when expressed in L.min but long-distance runners had the highest V0(2max)in mL.kg.min. However, the ANCOVA identified no difference in "mass independent" V0(2max) between the five "pure" endurance sports (runners, rowers, and triathletes) (P > 0.05) with the two racket sports being significantly lower. The body mass covariate exponent was inflated, estimated as 0.94. The results from study 2 estimated calf and thigh leg muscle masses to increase in proportion to body mass, and, respectively.
Conclusions:
After having controlled for differences in body mass, V0(2max) did not differ between pure endurance sports (P > 0.05). Assuming that athletes' thigh muscle mass increases in proportion to body mass as observed in study 2, a similar disproportional increase in V0(2max) would be anticipated, providing a plausible explanation for the inflated mass exponent associated with V0(2max) identified in this and other studies.
To investigate the effect of endurance training on physiological characteristics during circumpubertal growth, eight young runners (mean starting age 12 years) were studied every 6 months for 8 years. Four other boys served as untrained controls. Oxygen uptake (VO2) and blood lactate concentrations were measured during submaximal and maximal treadmill running. The data were aligned with each individual's age of peak height velocity. The maximal oxygen uptake (VO2max; ml.kg-1.min-1) decreased with growth in the untrained group but remained almost constant in the training group. The oxygen cost of running at 15 km.h-1 (VO2 15, ml.kg-1.min-1) was persistently lower in the trained group but decreased similarly with age in both groups. The development of VO2max and VO2 15 (l.min-1) was related to each individual's increase in body mass so that power functions were obtained. The mean body mass scaling factor was 0.78 (SEM 0.07) and 1.01 (SEM 0.04) for VO2max and 0.75 (SEM 0.09) and 0.75 (SEM 0.02) for VO2 15 in the untrained and trained groups, respectively. Therefore, expressed as ml.kg-0.75.min-1, VO2 15 was unchanged in both groups and VO2max increased only in the trained group. The running velocity corresponding to 4 mmol.l-1 of blood lactate (nu la4) increased only in the trained group. Blood lactate concentration at exhaustion remained constant in both groups over the years studied. In conclusion, recent and the present findings would suggest that changes in the oxygen cost of running and VO2max (ml.kg-1.min-1) during growth may mainly be due to an overestimation of the body mass dependency of VO2 during running.(ABSTRACT TRUNCATED AT 250 WORDS)
Physiological responses to repeated bouts of short duration maximal-intensity exercise were evaluated. Seven male subjects performed three exercise protocols, on separate days, with either 15 (S15), 30 (S30) or 40 (S40) m sprints repeated every 30 s. Plasma hypoxanthine (HX) and uric acid (UA), and blood lactate concentrations were evaluated pre- and postexercise. Oxygen uptake was measured immediately after the last sprint in each protocol. Sprint times were recorded to analyse changes in performance over the trials. Mean plasma concentrations of HX and UA increased during S30 and S40 (P less than 0.05), HX increasing from 2.9 (SEM 1.0) and 4.1 (SEM 0.9), to 25.4 (SEM 7.8) and 42.7 (SEM 7.5) mumol.l-1, and UA from 372.8 (SEM 19) and 382.8 (SEM 26), to 458.7 (SEM 40) and 534.6 (SEM 37) mumol.l-1, respectively. Postexercise blood lactate concentrations were higher than pretest values in all three protocols (P less than 0.05), increasing to 6.8 (SEM 1.5), 13.9 (SEM 1.7) and 16.8 (SEM 1.1) mmol.l-1 in S15, S30 and S40, respectively. There was no significant difference between oxygen uptake immediately after S30 [3.2 (SEM 0.1) l.min-1] and S40 [3.3 (SEM 0.4) l.min-1], but a lower value [2.6 (SEM 0.1) l.min-1] was found after S15 (P less than 0.05). The time of the last sprint [2.63 (SEM 0.04) s] in S15 was not significantly different from that of the first [2.62 (SEM 0.02) s]. However, in S30 and S40 sprint times increased from 4.46 (SEM 0.04) and 5.61 (SEM 0.07) s (first) to 4.66 (SEM 0.05) and 6.19 (SEM 0.09) s (last), respectively (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Oxygen uptake during treadmill running was measured at submaximal and maximal intensities in six different groups of endurance athletes (N = 134) and in seven endurance-trained men. The relationship between body mass (M) and oxygen uptake (VO2) was evaluated by deriving the exponent b in the equation VO2 = a.Mb. Thus, if b = 1, the oxygen uptake increases in proportion to body mass and oxygen uptake per kg is independent of body mass; if b less than 1, than the oxygen uptake per kg is inversely related to body mass. The exponent b was found to be less than unity for all groups for both submaximal (b = 0.76, s = 0.06) and maximal oxygen uptake (b = 0.71, s = 0.05). These results indicate that neither submaximal nor maximal oxygen uptake increases in proportion to body mass during running. The relationship between submaximal oxygen uptake and body mass observed in this study may explain why the oxygen uptake per kg of body mass has been found to be higher for children than for adults.
A maximal multistage 20 m shuttle run test was designed to determine the maximal aerobic power of schoolchildren, healthy adults attending fitness class and athletes performing in sports with frequent stops and starts (e.g. basketball, fencing and so on). Subjects run back and forth on a 20 m course and must touch the 20 m line; at the same time a sound signal is emitted from a prerecorded tape. Frequency of the sound signals is increased 0.5 km h-1 each minute from a starting speed of 8.5 km h-1. When the subject can no longer follow the pace, the last stage number announced is used to predict maximal oxygen uptake (VO2max) (Y, ml kg-1 min-1) from the speed (X, km h-1) corresponding to that stage (speed = 8 + 0.5 stage no.) and age (A, year): Y = 31.025 + 3.238 X - 3.248A + 0.1536AX, r = 0.71 with 188 boys and girls aged 8-19 years. To obtain this regression, the test was performed individually. Right upon termination VO2 was measured with four 20 s samples and VO2max was estimated by retroextrapolating the O2 recovery curve at time zero of recovery. For adults, similar measurements indicated that the same equation could be used keeping age constant at 18 (r = 0.90, n = 77 men and women 18-50 years old). Test-retest reliability coefficients were 0.89 for children (139 boys and girls 6-16 years old) and 0.95 for adults (81 men and women, 20-45 years old).(ABSTRACT TRUNCATED AT 250 WORDS)
The aim of this experiment was to estimate the relative contribution of the various energy delivery systems during maximal exercise tests of short duration. Twenty-five males were submitted to a VO2max test and 10-, 30-, and 90-s maximal ergocycle tests. Expiratory gases were collected with a Douglas bag during the entire 30-s test and continuously monitored with an open-circuit system during the 90-s test. Estimates of the phosphagenic component represented approximately 55%-60% of the energy expenditure during the 10-s work performance. Results of the 30-s test indicated that the relative contributions of the energy systems were 23%, 49%, and 28% for the phosphagenic, glycolytic, and oxidative pathways, respectively. For the 90-s test, these estimates were 12%, 42%, and 46% for the three metabolic systems. The highest contribution of each system during the 90-s was obtained from 5 to 15 s for the phosphagenic component, from 16 to 30 s for the glycolytic, and from 61 to 75 s for the aerobic energy systems. During the 90-s test, VO2max was reached after approximately 60 s. It is concluded that the 30 and 90 s are not strictly anaerobic although they all have a large anaerobic component.
Physiological Aspects of Sport Training and Performance, Second Edition, updates and expands on the popular first edition, providing an in-depth discussion of physiological adaptation to exercise. Students will learn the importance of an evidence-based approach in prescribing exercise, while sports medicine professionals and health care providers will appreciate using the text as a primary reference on conditioning and performance of athletes. A range of topics are covered, including environmental influences on performance, hydration status, sport nutrition, sport supplements, and performance-enhancing drugs. The book is focused on physiological adaptation to exercise with a goal of providing practical applications to facilitate exercise prescriptions for a variety of athletes.
Physiological Aspects of Sport Training and Performance, Second Edition, is organized into five parts. The first part examines physiological adaptation and the effects of various modes of training on biochemical, hormonal, muscular, cardiovascular, neural, and immunological adaptations. The second part covers principles of exercise training and prescription. The third part discusses nutrition, hydration status, sport supplementation, and performance-enhancing drugs. The fourth part focuses on environmental factors and their influence on sport performance. The fifth and final part is focused on how certain medical and health conditions influence sport performance.
Updates in this second edition focus on cutting-edge knowledge in sport science and sports medicine, including the latest information on physiological adaptations to exercise; current trends for training for power, speed, and agility; eye-opening discussions on sport supplementation and performance-enhancing drugs; data on training with medical conditions such as diabetes and exercise-induced bronchospasm; and groundbreaking information on training in heat and cold and at altitude. In addition, new chapters offer a practical approach to the yearly training program and sudden death in sport.
This online edition of the text includes access to videos of over 40 drills being performed in their entirety, including a dynamic warm-up routine video features 10 warm-up exercises.
The purpose of this study was to determine the effects of hip position and angular velocity on quadriceps and hamstring peak torque and on the hamstring/quadriceps (H/Q) ratio during maximal eccentric force. The dominant knee of 14 normal subjects (seven males and seven females) was tested in seated and supine positions at velocities of 60 and 180 deg/sec. Testing was completed using the Kinetic Communicator isokinetic dynamometer (Chattex Corp., Chattanooga, TN) and peak torque was corrected for gravity. The results showed that (a) the quadriceps (p <.001) produced significantly greater peak torque than the hamstrings, (b) both muscle groups produced significantly greater peak torque in the seated position (p <.001) than in the supine position and at 180 deg/sec (p <.05) than at 60 deg/sec, and (c) H/Q ratios were significantly greater in the seated position (p <.01) and at 180 deg/sec (p <.05) than in the supine position and at 60 deg/sec. The findings of this study suggest that the quadriceps and hamstring peak eccentric torque and H/Q ratio are influenced by hip position and angular velocity.
Purpose:
The purpose of this study was to assess research aimed at measuring performance enhancements that affect success of individual elite athletes in competitive events.
Analysis:
Simulations show that the smallest worthwhile enhancement of performance for an athlete in an international event is 0.7-0.4 of the typical within-athlete random variation in performance between events. Using change in performance in events as the outcome measure in a crossover study, researchers could delimit such enhancements with a sample of 16-65 athletes, or with 65-260 in a fully controlled study. Sample size for a study using a valid laboratory or field test is proportional to the square of the within-athlete variation in performance in the test relative to the event; estimates of these variations are therefore crucial and should be determined by repeated-measures analysis of data from reliability studies for the test and event. Enhancements in test and event may differ when factors that affect performance differ between test and event; overall effects of these factors can be determined with a validity study that combines reliability data for test and event. A test should be used only if it is valid, more reliable than the event, allows estimation of performance enhancement in the event, and if the subjects replicate their usual training and dietary practices for the study; otherwise the event itself provides the only dependable estimate of performance enhancement. Publication of enhancement as a percent change with confidence limits along with an analysis for individual differences will make the study more applicable to athletes. Outcomes can be generalized only to athletes with abilities and practices represented in the study.
Conclusion:
estimates of enhancement of performance in laboratory or field tests in most previous studies may not apply to elite athletes in competitive events.
In an attempt to develop a new measure of agility in the horizontal plane, this study examines several tests, including: the Illinois agility test, the 20m dash and two new tests - the Up and Back (UAB) and 505 tests, which both involve a short sprint and a reversal of direction. Eighteen subjects performed the tests in a randomised order. A strobe video and time were used to record the displacement data of the subjects, over set intervals, in the UAB and 505 tests. These data were then smoothed using a least-squares polynomial, and differentiated to produce a velocity and acceleration values. Times were recorded for the completion of the Illinois agility test and the 20m dash. The results for the four tests and the derived velocity and acceleration values were subjected to a correlation matrix. Significant correlations were found between the 505 test and acceleration values, but not with velocity values. The other tests correlated significantly with each other. It is concluded that the UAB test and Illinois Agility test are not purely agility tests because of their significant relationships with the 20m dash. The 505 test, however, has no significant correlation with velocity, but rather with acceleration. Therefore, the 505 test is seen as the test which best isolates agility in the horizontal plane.
A methodology to assess work rate in competitive professional football was designed and validated. The technique required monitoring by observation the intensity and extent of discrete activities during match play and was found to have a measurement error of less than one percent. Performance was observed over 51 games. A complete match typically involved approximately nine hundred separate movement activities per player. The overall distance covered per game was observed to be a function of positional role, the greatest distance covered in outfield players being in mid fielders, the least in centre backs.
Isokinetic contraction is the muscular contraction that accompanies constant velocity limb movements around a joint. The velocity of movement is maintained constant by a special dynamometer. The resistance of the dynamometer is equal to the muscular forces applied throughout the range of movement. This method allows the measurement of the muscular forces in dynamic conditions and provides optimal loading of the muscles.
However, during movements in the vertical plane, the torque registered by the dynamometer is the resultant torque produced by the muscular and gravitational forces. The error depends on the angular position and the torque potential of the tested muscle group. Several methods have been developed for the correction of gravitational errors in isokinetic data.
The torque output also contains artefacts that are associated with the inertial forces during acceleration and deceleration periods before the development of the constant preset angular velocity. For an accurate assessment of muscle function, only constant velocity data should be analysed.
The most frequently used isokinetic parameters are the maximum torque and the angular position where it was recorded, the torque output at different angular velocities of movement, the torque ratio of reciprocal muscle groups and the torque output during repeated contractions.
The unique features of isokinetic dynamometry are optimal loading of the muscles in dynamic conditions and constant preselected velocity of movement. These features provide safety in the rehabilitation of patients with muscular and ligamentous injuries. Isokinetic dynamometry has also been used for the training of various muscle groups in order to improve the muscular performance in dynamic conditions. The movement velocity of different activities can be simulated during training in order to improve the training effect.
Data acquisition and analysis have been improved by using computer systems interfaced to isokinetic dynamometers. Recently developed computer systems provide correction for gravitational and inertial errors, accurate computation of isokinetic parameters and real-time display of the torque output.
This article argues that American public administrative thought rests on philosophically pragmatic premises that treat praxis as an exercise in relating explanatory theories to empirically derived facts. This methodocentric "knowledge production" approach directs attention away from a rhetorical "normative judgment" approach that undergirds and legitimizes both legal and administrative practices. The latter approach to praxis emphasizes the dialogic relation of enduring values and principles to changing circumstances. It brings concerns for permanence, stability, aspiration, moral teaching, public good, restraint, and discovery to bear on these practices. It exposes both their rhetorical foundations and the centrality of law as a focal point for administrative wisdom. This "jurisprudential" approach to praxis ties public administrators to constitutional foundations and entails dramatically different emphases in their education and training.
This is the first in a series of papers broadly titled ‘Research Without Tears’ that will discuss fundamental and sometimes controversial areas of research methods. In general, papers in this section aim to inform or update the readership of theoretical and practical issues for research in the clinical sciences. Some of the review papers will be conceptual in nature whilst others may address specific topics related to research design and data handling. It is hoped that this will facilitate the individuals and teams to complete and disseminate their research. Another important aim of these papers will be to try to demystify the chosen topics for those people whose role is not exclusively research orientated.The aim of this specific review paper is to address the concept of validity in clinical research. This article will be followed, firstly, by a review paper that will investigate the topic of reliability in clinical research, and then by an original research article that places the determination of validity and reliability within a specific clinical context. The current paper will initially define key components of validity with regard to the general aims of research and the research design. This will include definitions of internal, external and ecological validity. Threats to internal and external validity will be discussed, as will remedies to these treats through the application of appropriate sampling and design. This paper will then investigate the narrower concept of the validity of the measuring tool or process. A brief definition will be followed by a discussion of the processes by which validity may be determined. Future papers will address other issues of relevance to the readership. The Editorial Board welcomes any specific ideas and/or submissions.
An increase in exercise capacity depends on the magnitude of increase in maximum aerobic capacity. Central and peripheral factors may limit oxygen uptake. Central oxygen delivery depends on cardiac output and maximal arterial oxygen content. Peripheral extraction of the delivered oxygen is expressed as a-v̅ O2. With increasing intensities of exercise, the respiratory system may become limiting in some trained individuals. Most studies have shown a higher stroke volume in maximal as well as submaximal exercise in the trained vs untrained individuals A variety of peripheral factors determine vascular tone. Maximal oxygen uptake depends on all components of the oxygen transporting system, but stroke volume appears to be the prime determinant in the trained subject. At maximum exercise the capacity of the muscle capillary network is never reached.
The purpose of physiological testing (J.D. MacDougall and H.A. Wenger) what do tests measure? (H.J. Green) testing strength and power (D.G. Sale) testing aerobic power (J.S. Thoden) testing anaerobic power and capacity (C. Bouchard, Albert W. Taylor, Jean-Aime Simoneau, and Serge Dulac) Kknanthropometry (WD. Ross and M.J. Marfell-Jones) testing flexibility (C.L. Hubley-Kozey) evaluating the health status of the athlete (R. Backus and D.C. Reid) modelling elite athletic performance (E.W. Banister).
The energetics of repeated sprint efforts are poorly defined. To investigate this topic the performance of two separate groups of subjects on cycling (6 x 6 s maximal efforts, departing every 30 s) and running (6 x 40 m maximal efforts, departing every 30 s) repeated sprint ability (RSA) tests was correlated against performance measures of anaerobic power (cycling: work done in 10 s and Peak Power; running: 10 m and 40 m sprint time and vertical jump), anaerobic work capacity (cycling: work done in 30 s; running: 400 m sprint time) and aerobic power V̇O2 max). The absolute test scores for each RSA test (cycling: total work done in 6 efforts; running: total time taken for 6 efforts) were significantly correlated with all criterion energy system performance measures (p < 0.01), but more strongly with anaerobic power (r = 0.67-0.94) and work capacity (r = 0.91) measures, rather than aerobic power (r = 0.49-0.66). The cycling relative test score (% decrement over 6 efforts) was significantly correlated to anaerobic (r = 0.60-0.68) (p < 0.01) and aerobic (r = -0.55) (p < 0.05) power measures, but not to anaerobic work capacity. The running % decrement score was only significantly correlated with V̇O2 max (r = -0.62) (p < 0.01). Therefore, while RSA seems to be dependent to some degree on the level of each of anaerobic power and work capacity and aerobic power, the degree of association differs when the RSA test performance is measured in absolute or relative terms. The results suggest that the power of the anaerobic energy systems are major determinants of the total work or time RSA scores and hence repeated power or speed. The aerobic energy system is more closely associated with the RSA % decrement score and hence overall fatigue and recovery between sprints. Some implications for the training of RSA are also discussed.
Eight male subjects were studied during incremental bicycle exercise. From the forearm, arterial and venous blood lactate concentrations were measured every minute until exhaustion. There was a statistically significant difference (P<0.01) in the points at which the arterial and venous blood lactates began to increase above the resting level. The onset of increase of lactate in arterial blood occurred at 1.000.07 lmin–1 in
[(V)\dot]\dot V
O2 (mean SEM), which corresponded to 37.01.5% of
[(V)\dot]\dot V
O2max. Its venous counterpart occurred at 1.500.17 lmin–1 in
[(V)\dot]\dot V
O2, 55.03.8% of
[(V)\dot]\dot V
O2max. The arterio-venous lactate difference became greater after the onset of increase in arterial blood lactate (anaerobic threshold), presumably as consequence of lactate utilization by the forearm muscles.It was concluded that the onset of blood lactate increase differs according to the sites of blood sampling, which should be considered for the interpretation of anaerobic threshold.
Conventionally, the hamstring:quadriceps strength ratio is calculated by dividing the maximal knee flexor (hamstring) moment by the maximal knee extensor (quadriceps) moment measured at identical angular velocity and contraction mode. The agonist-antagonist strength relationship for knee extension and flexion may, however, be better described by the more functional ratios of eccentric hamstring to concentric quadriceps moments (extension), and concentric hamstring to eccentric quadriceps moments (flexion). We compared functional and conventional isokinetic hamstring: quadriceps strength ratios and examined their relation to knee joint angle and joint angular velocity. Peak and angle-specific (50 degrees, 40 degrees, and 30 degrees of knee flexion) moments were determined during maximal concentric and eccentric muscle contractions (10 degrees to 90 degrees of motion; 30 and 240 deg/sec). Across movement speeds and contraction modes the functional ratios for different moments varied between 0.3 and 1.0 (peak and 50 degrees), 0.4 and 1.1 (40 degrees), and 0.4 and 1.4 (30 degrees). In contrast, conventional hamstring:quadriceps ratios were 0.5 to 0.6 based on peak and 50 degrees moments, 0.6 to 0.7 based on 40 degrees moment, and 0.6 to 0.8 based on 30 degrees moment. The functional hamstring:quadriceps ratio for fast knee extension yielded a 1:1 relationship, which increased with extended knee joint position, indicating a significant capacity of the hamstring muscles to provide dynamic knee joint stability in these conditions. The evaluation of knee joint function by use of isokinetic dynamometry should comprise data on functional and conventional hamstring:quadriceps ratios as well as data on absolute muscle strength.
The major purpose of the present study was to examine whether there exists a relationship between preseasonal physiological tests and performance results in the soccer league. Further, it investigated maximal oxygen uptake and maximal strength in proportion to body mass for soccer players. A secondary aim was to establish some normative data of Norwegian elite soccer players.
Two teams from the Norwegian elite soccer league participated in the study.
The present study supports previous investigations indicating a positive relationship between maximal aerobic capacity, physical strength, and performance results in the elite soccer league. It is concluded that for soccer players, maximal oxygen uptake should be expressed in relation to body mass raised to the power of 0.75 and maximal strength in relation to body mass raised to the power of 0.67, when the aim is to evaluate maximal aerobic capacity when running and strength capacity among players with different body mass. Midfield players had significantly higher maximal oxygen uptake compared with defense players using the traditional expression, mL x kg(-1) x min(-1), while no significant differences were found expressing maximal oxygen uptake either absolutely (L x min[-1]) or in relation to body mass raised to the power of 0.75 (mL x kg[-0.75] x min[-1]) among players grouped by position. There was a significant correlation (r = 0.61, P < 0.01) between squat IRM and vertical jump height. Vertical jump heights for defense and forward players were significantly higher compared with midfield players. Mean results from the laboratory test were 63.7 mL x kg(-1) x min(-1) or 188.6 mL x kg[-0.75] x min(-1) for maximal oxygen uptake, 150 kg or 8.0 kg x mb(-0.67) for 90 degrees squats, 79.9 kg or 4.4 kg x mb(-0.67) for bench press. Mean values of vertical jump height were 54.9 cm.
Succinate dehydrogenase (SDH) and cytochrome oxidase activities in the lateral vastus of the human quadriceps femoris muscle together with total body VO2 max were followed during an 8-10 week period of endurance training (n = 13) and a successive 6 week period without training (n = 8). During the training period there was a gradual increase in both VO2 max and muscle oxidative enzyme activities, all being significantly different from the pre-training levels after 3 weeks of training. After 8 weeks of training VO2 max was 19%, vastus lateralis SDH 32%, and cytochrome oxidase activity 35% above the pre-training levels respectively. 6 weeks post training VO2 max was still 16% above the pre-training level, and not significantly different from the level at the end of training (p greater than 0.2). In contrast vastus lateralis SDH activity had returned to the pre-training level. Cytochrome oxidase activity had returned to the pre-training level within two weeks post-training. The significantly faster post-training decline in skeletal muscle oxidative enzyme activities in contrast to that of the VO2 max indicates that an enhancement of the oxidative potential in skeletal muscle is not a necessity for a high VO2 max. Moreover, the fast return to the pre-training level of both SDH and cytochrome oxidase activities indicate a high turnover rate of enzymes in the TCA cycle as well as the respiratory chain.
Maximal aerobic power of 37 athletes (14 females and ten male cross-country skiers, eight male rowers and five male cyclists) was determined during uphill running on the treadmill and during maximal performance of their specific sport activity. For the skiers a significantly (P less than 0.005) higher VO2max was found during uphill skiing than during running, the differences being 2.9 and 3.1% for the females and males, respectively. The rowers and cyclists obtained a difference of 4.2 and 5.6%, respectively (P less than 0.01). The largest individual differences between the two test procedures were 12.2, 5.4, 14.3, and 7.9% for female and male cross-country skiers, rowers, and cyclists, respectively. It is concluded that in evaluation of maximal aerobic power of atheletes, it becomes important to select a work situation which allows optimal use of the specifically trained muscle fibres. This means that the test preferably should be identical with the subjects' specific sport activity, under the assumption that a reasonably large muscle mass is engaged during the performance.
The purpose of this study was to evaluate the physiological functions of a professional soccer team in the North American Soccer League (NASL). Eighteen players were evaluated on cardiorespiratory function, endurance performance, body composition, blood chemistry, and motor fitness measures near the end of their competitive season. The following means were observed: age, 26 yrs; height, 176 cm; weight 75.5 kg; resting heart rate, 50 beats/min; maximum heart rate (MHR), 188 beats/min; maximum oxygen intake (VO2 max), 58.4 ml/kg-min-1; maximum ventilation (VEmax BTPS), 154 L/min; body fat, 9.59%; 12-min run, 1.86 miles; and Illinois agility run, 15.6 secs. Results on resting blood pressure, serum lipids, vital capacity, flexibility, upper body strength, and vertical jump tests were comparable to values found for the sedentary population. Comparing the results with previously collected data on professional American Football backs indicated that the soccer players were shorter; lighter in body weight; higher in VO2 max (4 ml/kg-min-1) and body fat (1.8%); and similar in MHR, VE max, and VC. The 12-min run scores were similar to the initial values observed for the 1970 Brazilian World Cup Team. The agility run results were superior to data collected from other groups. Their endurance capabilities, agility, and low percent of body fat clearly differentiate them from the sedentary population and show them to be similar to that of professional American football backs.
Day-to-day variability and single-measurement reliability of selected isokinetic knee extension-flexion strength and endurance indices were assessed in 10 adult men and 8 adult women. On three occasions separated by at least 5 days, the subjects completed 4 reciprocal maximal voluntary contractions (MVC) at different angular velocities (1.05 rad.s-1 and 3.14 rad.s-1). The men also completed a muscular endurance test consisting of 30 reciprocal, MVC at 3.14 rad.s-1. Coefficient of variation, intra-class correlation coefficient and standard error of single-measurement scores support the continued use of gravity corrected peak torque (PT) and average peak torque (APT) as indices of isokinetic leg strength. Similarly, gravity corrected APT and total work should be the recommended indices of isokinetic leg muscular endurance in men. The results suggest that these isokinetic indices must be assessed using multiple day-to-day trial protocols adequately to describe performance capacity. Composite indices such as the ratio of Knee flexion to extension PT and fatigue measurements offer considerably reduced reliability and a greater potential for misinterpretation. The reliability of knee extension indices generally exceeds that of flexion indices. Similar variability and reproducibility of responses were observed between men and women and between reciprocal contractions performed at angular velocities of 1.05 rad.s-1 and 3.14 rad.s-1.
This paper examines how selected physiological performance variables, such as maximal oxygen uptake, strength and power, might best be scaled for subject differences in body size. The apparent dilemma between using either ratio standards or a linear adjustment method to scale was investigated by considering how maximal oxygen uptake (l.min-1), peak and mean power output (W) might best be adjusted for differences in body mass (kg). A curvilinear power function model was shown to be theoretically, physiologically and empirically superior to the linear models. Based on the fitted power functions, the best method of scaling maximum oxygen uptake, peak and mean power output, required these variables to be divided by body mass, recorded in the units kg 2/3. Hence, the power function ratio standards (ml.kg-2/3.min-1) and (W.kg-2/3) were best able to describe a wide range of subjects in terms of their physiological capacity, i.e. their ability to utilise oxygen or record power maximally, independent of body size. The simple ratio standards (ml.kg-1.min-1) and (W.kg-1) were found to best describe the same subjects according to their performance capacities or ability to run which are highly dependent on body size. The appropriate model to explain the experimental design effects on such ratio standards was shown to be log-normal rather than normal. Simply by taking logarithms of the power function ratio standard, identical solutions for the design effects are obtained using either ANOVA or, by taking the unscaled physiological variable as the dependent variable and the body size variable as the covariate, ANCOVA methods.
The metabolic and physiological responses to different exercise to rest ratios (E: R) (2:1, 1: l, 1:2) of eight subjects exercising at work rates approximately 10% above and below maximum oxygen uptake (\(\dot VO_{2 max} \)) were assessed. Each of the six protocols consisted of 15 1-min-long E : R intervals. Total work (kJ), oxygen uptake (\(\dot VO_2 \)), heart rate (f
c and plasma lactate concentrations were monitored. With increases in either E : R or work rate,\(\dot VO_2 \) andf
c increased (P <0.05). The average (15 min)\(\dot VO_2 \) andf
c ranged from 40 to 81 %, and from 62 to 91% of maximum, respectively. Plasma lactate concentrations nearly doubled at each E : R when work rate was increased from 90 to 110% of\(\dot VO_{2 max} \) and ranged from a low of 1.8 mmol -I−1 (1: 2–90) to a high of 10.7 mmol·1−1 (2:1–110). The 2:1–110 protocol elicited plasma lactate concentrations which were approximately 15 times greater than that of rest. These data suggest that plasma lactate concentrations during intermittent exercise are very sensitive to both work rate and exercise duration.
To study the physiological response to heavy training, seven male competitive cyclists intensified their normal training program for two weeks (IIT) in order to achieve a state of short-term overtraining. The subjects underwent a graded cycle ergometer test to exhaustion, an outdoor 8.5 km time trial and a computerized test to study reaction time and visual perception, before, during and after the two weeks of intensified training and after two weeks of recovery. Furthermore subjects kept a daily log in the form of a questionnaire. After two weeks of IIT all subjects showed symptoms of overtraining: the general state of well being declined as indicated by the questionnaire while performances on time trial (mean +/- SEM: 830 +/- 14 sec-871 +/- 19 sec), contests and maximal power output (mean +/- SEM: 336 7 watt-310 +/- 5 watt) declined significantly. Maximal (mean +/- SEM 11.8 +/- 1.1 mmol.l-1-5.9 +/- 0.5 mmol.l-1) and submaximal lactate values were significantly lowered during ergometer test after the IIT, while the workload at the 4 mmol point increased significantly (mean +/- SEM 234 +/- 10 watt-267 +/- 13 watt). Sleeping heart rate increased significantly (mean +/- SEM 49.5 +/- 9.3 BPM-54.3 +/- 8.8 BPM). Maximal heart rate (mean +/- SEM 185 +/- 3 BPM-178 +/- 2 BPM, mean heart rate during the time trial (mean +/- SEM 178 +/- 2 BPM-169 +/- 2 BPM) and VO2max (mean +/- SEM 4801 +/- 121 ml.min-1-4409 +/- 101 ml.min-1) were all significantly lowered by the IIT.(ABSTRACT TRUNCATED AT 250 WORDS)
Seven male subjects performed 15 x 40m sprints, on three occasions, with rest periods of either 120 s (R120), 60 s (R60) or 30 s (R30) between each sprint. Sprint times were recorded with four photo cells placed at 0, 15, 30 and 40 m. The performance data indicated that whereas running speed over the last 10 m of each sprint decreased in all three protocols (after 11 sprints in R120, 7 sprints in R60 and 3 sprints in R30), performance during the initial acceleration period from 0-15 m was only affected with the shortest rest periods increasing from (mean +/- SEM) 2.58 +/- .03 (sprint 1) to 2.78 +/- .04 s (spring 15) (p < .05). Post-exercise blood lactate concentration was not significantly different in R120 (12.1 +/- 1.3 mmol.l-1) and R60 (13.9 +/- 1.2 mmol.l-1), but a higher concentration was found in R30 (17.2 +/- .7 mmol.l-1) (p < .05). After 6 sprints there was no significant difference in blood lactate concentration with the different recovery durations, however, there were significant differences in sprint times at this point, suggesting that blood lactate is a poor predictor of performance during this type of exercise. Although the work bouts could be classified primarily as anaerobic exercise, oxygen uptake measured during rest periods increased to 52, 57 and 66% of maximum oxygen uptake in R120, R60 and R30, respectively. Evidence of adenine nucleotide degradation was provided by plasma hypoxanthine and uric acid concentrations elevated post-exercise in all three protocols. Post-exercise uric acid concentration was not significantly affected by recovery duration.(ABSTRACT TRUNCATED AT 250 WORDS)
This investigation was undertaken in an effort to establish physiological characteristics of soccer players and to relate them to positional roles. A total of 135 footballers (age 24.4 +/- 4.6 years) were assessed for body mass, % body fat, haemoglobin, maximal oxygen uptake (VO2 max), leg power, anaerobic capacity and speed prior to an English league season. The sample included 13 goalkeepers, 22 full-backs, 24 centre-backs, 35 midfield players and 41 forwards. The goalkeepers were significantly heavier (86.1 +/- 5.5 kg; P < 0.01) than all groups except the centre-backs, had significantly higher estimated body fat percentages than centre-backs, forwards, midfield players (P < 0.01) or full-backs (P < 0.05), significantly lower estimated VO2 max values (56.4 +/- 3.9 ml kg-1 min-1; P < 0.01) and were slowest over 60 m (12.71 +/- 0.42 s). The midfield players had the highest predicted VO2 max values (61.4 +/- 3.4 ml kg-1 min-1), this being significantly greater (P < 0.05) than for the centre-backs. The forwards were the fastest group over 60 m (12.19 +/- 0.30 s), being significantly quicker than goalkeepers or centre-backs (P < 0.01) and full-backs (P < 0.05). Anaerobic power, as well as knee extensor torques (corrected for body mass) and extensor-flexor ratios, were similar between groups. No difference in estimated body fat percentage was observed between any of the outfield players, and haemoglobin concentrations were similar among players of all positions.(ABSTRACT TRUNCATED AT 250 WORDS)
To evaluate exercise procedures to test the endurance capacity during soccer, individual results in laboratory and field tests were compared to physical performance during the match and further to performance during long term, intermittent exercise. Twenty professional soccer players were video-taped during competitive soccer matches, and the longest total distance (match-distance) and high intensity distance were determined. Blood lactate and maximum oxygen uptake (VO2max) were measured during treadmill running. The subjects also carried out a continuous and an interval field test. Furthermore, eight players performed a prolonged, soccer-specific, intermittent test to exhaustion. Muscle enzymes and morphological characteristics were determined in biopsy samples obtained from the m. gastrocnemius. The distance covered during the prolonged, intermittent test (mean: 16.3 km; range: 14.8-18.5 km) was not related to match-distance (r = 0.16), however, its correlation coefficient with high intensity distance covered during the match was 0.70. The interval field test distance was strongly correlated (r = 0.83) with the distance covered during the prolonged, intermittent test distance. VO2max (r = 0.64) and blood lactate concentrations during submaximal running (r = 0.58) were related to match-distance, but not to the prolonged intermittent test distance (r = 0.18 and r = 0.27, respectively). The muscle enzyme activities and the morphological variables were not related to match activities nor to prolonged, intermittent exercise performance.(ABSTRACT TRUNCATED AT 250 WORDS)
The force-velocity characteristics of skeletal muscle are such that maximal force is inversely related to the velocity of shortening. This relationship has been observed using isolated muscle preparations and intact muscle groups (e.g. knee extensors). Isokinetic dynamometry has revealed some specific physiological adaptations to different velocities of training: an increase in torque and power that are greater at or near the velocity of training; a transfer of torque gains to slower and faster angular velocities after intermediate velocity resistance training; increases in maximal oxygen consumption and cardiac output in response to circuit training; increases in anaerobic power output; changes in skeletal muscle size and changes in myofibrillar ATPase activity; and new applications for rehabilitation of muscular and ligamentous injuries, and post-coronary patients.
In order to study the movement pattern of soccer players, 14 top-level players were filmed during several competitive matches. In addition, the relationship between the observed activity during match play and blood lactate values was examined. The mean distance covered during competitive matches was 10.80 km, and the average individual difference between matches was 0.92 km, with no difference in regard to high intensity activities. Midfielders covered a 10% longer (p less than 0.05) distance (11.4 km) than defenders and forwards, with no difference concerning high intensity running. There was a significant correlation (r = 0.61, p less than 0.05) between the amount of high intensity running during the match and lactate concentration in the blood. The results suggest that high intensity running can be used for making comparisons in soccer and that the interpretation of blood lactate in soccer is limited to giving an indication of the type of activity that has been carried out a few minutes before sampling.
This study analyzed forces in the tibiofemoral and patellofemoral joints during isokinetic exercise using an analytical biomechanical model. The results show that isokinetic exercise can produce large loads on these joints, especially during extension exercises. The tibiofemoral compressive force (4.0 body weight) is approximately equal to that obtained during walking but it occurs at 55 degrees of knee flexion. Anterior shear forces (resisting force to anterior drawer) exist during extension exercise at less than 40 degrees of knee flexion, with a maximum of 0.3 body weight. Posterior shear forces (resisting force to posterior drawer) exist during extension exercise at knee joint angles greater than 40 degrees and during the flexion portion of isokinetic exercise. The maximum posterior shear force is 1.7 body weight. The patellofemoral joint can encounter loads as high as 5.1 body weight which are 10 times higher than during straight leg raises. These results suggest that isokinetic exercise should be used cautiously in patients with knee lesions.
Isokinetic contraction is the muscular contraction that accompanies constant velocity limb movements around a joint. The velocity of movement is maintained constant by a special dynamometer. The resistance of the dynamometer is equal to the muscular forces applied throughout the range of movement. This method allows the measurement of the muscular forces in dynamic conditions and provides optimal loading of the muscles. However, during movements in the vertical plane, the torque registered by the dynamometer is the resultant torque produced by the muscular and gravitational forces. The error depends on the angular position and the torque potential of the tested muscle group. Several methods have been developed for the correction of gravitational errors in isokinetic data. The torque output also contains artefacts that are associated with the inertial forces during acceleration and deceleration periods before the development of the constant preset angular velocity. For an accurate assessment of muscle function, only constant velocity data should be analysed. The most frequently used isokinetic parameters are the maximum torque and the angular position where it was recorded, the torque output at different angular velocities of movement, the torque ratio of reciprocal muscle groups and the torque output during repeated contractions. The unique features of isokinetic dynamometry are optimal loading of the muscles in dynamic conditions and constant preselected velocity of movement. These features provide safety in the rehabilitation of patients with muscular and ligamentous injuries. Isokinetic dynamometry has also been used for the training of various muscle groups in order to improve the muscular performance in dynamic conditions. The movement velocity of different activities can be simulated during training in order to improve the training effect. Data acquisition and analysis have been improved by using computer systems interfaced to isokinetic dynamometers. Recently developed computer systems provide correction for gravitational and inertial errors, accurate computation of isokinetic parameters and real-time display of the torque output.
This study determined the metabolic responses to different exercise:rest protocols during circuit exercise using hydraulic resistance. In experiment 1, nine subjects underwent nine different 27 min exercise circuits. There were three variations of three exercise:rest protocols (2:1, 1:1, 1:2). The VO2 for the nine circuits averaged (mean +/- SEM) 1.94 +/- 0.03 l.min-1 (43% of treadmill VO2max), with the largest difference between the protocols being 13%. Heart rate averaged 152.2 +/- 3.1 beats.min-1, with the largest difference between the protocols being 8%. Increasing the exercise duration per minute or the number of exercise bouts per minute had minimal effects on the mean VO2 and heart rate response to hydraulic resistive exercise. In experiment 2, nine subjects underwent three different 9 min exercise circuits using exercise:rest protocols of 2:1, 1:1, and 1:2 while work and VO2 were simultaneously measured. Surprisingly, increases in work were not necessarily accompanied by corresponding increases in VO2.
The purpose of the present study was to examine the validity of using a 20 m progressive shuttle run test to estimate maximal oxygen uptake. Running ability was described as the final level attained on the shuttle run test and as time on a 5 km run. Maximal oxygen uptake (VO2 max) was determined directly for seventy-four volunteers (36 men, 38 women) who also completed the shuttle run test. Maximal oxygen uptake values were 58.5 +/- 7.0 and 47.4 +/- 6.1 ml.kg-1.min-1 for the men and women respectively (mean +/- SD, P less than 0.01). The levels attained on the shuttle run test were 12.6 +/- 1.5 (men) and 9.6 +/- 1.8 (women; P less than 0.01). The correlation between VO2 max and shuttle level was 0.92. The correlation between VO2 max and the 5 km run was -0.94 and the correlation between both field tests was -0.96. The results of this study suggest that a progressive shuttle run test provides a valid estimate of VO2 max and indicates 5 km running potential in active men and women.
To determine the effect of (1) a 1 min pause between the working periods; (2) sites of blood samples, on the venous lactate kinetics, the 'anaerobic threshold' (AT) and the 'lactate threshold of 4 mM' (T[La]), five active young men performed two different kinds of incremental bicyle exercise. Two kinds of blood samples were obtained: (1) arterialized samples by micro-ponctures from hyperemic earlobes (a); (2) venous samples, every fifteen sec, by a catheter inserted into the forearm (v). The two incremental exercise tests consisted of workloads of 4 min with power increments of 30 watts. Each loading level of test-1 was followed by a 1 min rest break whereas the working periods in test-0 were not interrupted. The venous lactate values were significantly higher in test-1 than in test-0 (p<0.05) for the workloads > AT. Therefore, when T[La]v was expressed as a function of V̇O2 (l/min), it was significantly lower in test-1 (p<0.05). Moreover, the workload corresponding of the T[La], in test-0 were significantly higher when blood samples were venous (p<0.05). It was conducted that there were effects of: (1) a 1 min pause between working periods on venous lactate kinetic and T[La] (l/min); (2) the two kinds of blood samples, on work intensity corresponding to T[La].
The knee extensor and knee flexor muscle groups in three groups of young soccer players were tested with a Cybex II isokinetic dynamometer and compared with adults. Muscle strength increased with age. The largest gain was observed in young players aged 16-17 years whose quadriceps was the most modified muslce group giving the lowest H/Q ratio.
Analysis of the regression equations obtained for torque values at 30°s⁻¹ and 180°s⁻¹ revealed that there were two distinct groups : under 16 and over 16. After reaching 16 years of age, the increase in muslce strength is greater at low velocity than at high velocity.
Isokinetic dynamometers have frequently been used to determine in vivo properties of human skeletal muscles. In these investigations the moments recorded by the dynamometer were often (implicitly) assumed to be the same as the joint moments produced by muscles. This assumption may have contributed to the conflicting results about in vivo muscle properties of human skeletal muscles that are reported in the literature. The purpose of this paper is to present a method for calculating the resultant joint moments from the moments recorded using a Cybex II dynamometer and to determine the differences between these two moments for some typical exercise conditions. The differences between these these moments are shown to be due to (a) gravitational effects, (b) inertial effects, and (c) non-rigidity of the Cybex arm/shank-foot system. The results obtained suggest that the moments recorded using the dynamometer should not be used to derive muscle properties without taking into account the relationship between the resultant joint moments and the moments measured using an isokinetic dynamometer.
A new computerized dynamometer (the SPARK System) is described. The system can measure concentric and eccentric muscle strength (torque) during linear or nonlinear acceleration or deceleration, isokinetic movements up to 400 degrees.s-1, and isometric torque. Studies were performed to assess: I. validity and reproducibility of torque measurements; II. control of lever arm position; III. control of different velocity patterns; IV. control of velocity during subject testing; and, V. intra-individual reproducibility. No significant difference was found between torque values computed by the system and known torque values (p greater than 0.05). No difference was present between programmed and external measurement of the lever arm position. Accelerating, decelerating and isokinetic velocity patterns were highly reproducible, with differences in elapsed time among 10 trials being never greater than 0.001 s. Velocity during concentric and eccentric isokinetic quadriceps contractions at 30 degrees.s-1, 120 degrees.s-1 and 270 degrees.s-1 never varied by more than 3 degrees.s-1 among subjects (N = 21). Over three days of testing, the overall error for concentric and eccentric quadriceps contraction peak torque values for 5 angular velocities between 30 degrees.s-1 and 270 degrees.s-1 ranged from 5.8% to 9.0% and 5.8% to 9.6% respectively (N = 25). The results indicate that the SPARK System provides valid and reproducible torque measurements and strict control of velocity. In addition, the intra-individual error is in accordance with those reported for other similar devices.