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Abstract

Purpose: To analyze and compare the effects of 4 different resisted sprint training (RST) modalities on youth soccer players' performance after 8 weeks of training. Methods: Forty-eight youth soccer players were first randomly assigned to 4 groups and only then completed 8 weeks of RST: horizontal resisted sprint, vertical resisted sprint (VRS), combined resisted sprint, and unresisted sprint. Performance in horizontal and vertical jumps, sprint, and change of direction (COD) ability were assessed 1 week before and after the training intervention. Magnitude-based inference analysis was performed for calculating within-group pre-post differences. In addition, an analysis of covariance test was performed for between-group comparison, using the pretest values as covariates. After that, the analysis of covariance P values and the effect statistic were transformed to magnitude-based inference. Results: Within-group outcomes showed that all resisted training modalities experienced improvements in sprint (small to moderate) and COD (small to large) performance. Moreover, all groups, except unresisted sprint, enhanced the horizontal jump performance. However, only VRS improved on vertical jump. Between-group comparison outcomes revealed that only VRS improved the sprint time compared with horizontal resisted sprint (moderate) and COD performance compared with all groups (moderate to large). In addition, VRS enhanced the countermovement jump performance (small to large) compared with the other groups. Conclusions: Independent of the orientation of the resistance applied, RST is an effective training method for improving sprinting and COD performance. Nevertheless, VRS may promote greater improvements on sprint and COD ability and have a positive additional effect on countermovement jump performance and the reduction of COD deficit.

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... These tendencies in speed training are certainly influenced by: 1) the very high specificity of sprinting technique and mechanics, which requires SCCs to use the most specific training methods (i.e., maximum sprints and running technique) to properly enhance speed-related qualities [60][61][62], and 2) the positive effects of both strength and plyometric training interventions on speed performance, which were consistently observed in numerous investigations involving soccer players from different age-categories and performance levels [35,41,59,63]. Lastly, the fact that a substantial number of SCCs (55%) prescribe resisted sprints may also be due to the reasons mentioned above, such as: 1) these exercises provide a specific mechanical overload when properly prescribed, allowing athletes to mimic unloaded sprints with an added resistance [64,65] [56,59,73]. Overall, about 70% of SCCs prescribe veryshort flexibility workouts (i.e., ≤ 15 minutes) and 20% of them do not include flexibility training sessions in their training programs. ...
... , and 2) several recent studies have demonstrated the effectiveness of this training strategy on the speed performance of soccer players[17,64,66]. In general, the speed training strategies used by Brazilian soccer SCCs are aligned with the strategies adopted by SCCs from different countries and can be considered as evidencebased practices.Plyometric exercises are mostly prescribed for speed development by 86% of Brazilian SCCs. ...
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Brazil is the leading global exporter of soccer players, with approximately 2,000 international transfers to different clubs per year. Although Brazilian players compete in the most prestigious soccer leagues worldwide, the habitual training methods, strategies, and routines of Brazilian soccer strength and conditioning coaches (SCCs) are undocumented. This study used a standard online survey to collect and characterize the strength and conditioning practices of Brazilian soccer SCCs. Forty-nine SCCs (age: 40.4 ± 7.5 years; professional experience: 15.3 ± 7.5 years;) working in Brazilian professional soccer teams participated in this study. The survey consisted of eight sections: 1) background information; 2) muscular strength-power development; 3) speed training; 4) plyometrics; 5) flexibility training; 6) physical testing; 7) technology use; and 8) programing. Results indicated that training and testing practices of Brazilian SCCs are strongly affected by the congested fixture schedules, extensive traveling distances, and socio-economic disparities between different regions of the country. We describe all these different strategies and methods in detail, providing a comprehensive view and a critical examination of Brazilian soccer strength and conditioning practices. Brazilian SCCs and professional soccer organizations can use the findings from this study to develop training strategies and customize education programs. Practitioners from other countries can use this information to design training programs closely tailored to the background of Brazilian athletes, which may support their adaptation to different competitive scenarios and game demands, such as those found in the most important soccer leagues worldwide.
... attributable to several variables including the resisted sprint training modalities, the loads accounting, 27 the frequency of sessions, the duration of the training period and the testing protocols (4,5,12,27). 28 From practical point of view, we assume that such information would be important for fitness coaches 29 to properly prescribe resisted sprint training. 30 Carlos-Vivas et al. (5) have examined the effects of horizontal resisted sprint, vertical resisted 31 sprint, combined resisted sprint, and un-resisted sprint on performance in horizontal and vertical 32 jumps, sprint, and change of direction ability in youth soccer players. ...
... 28 From practical point of view, we assume that such information would be important for fitness coaches 29 to properly prescribe resisted sprint training. 30 Carlos-Vivas et al. (5) have examined the effects of horizontal resisted sprint, vertical resisted 31 sprint, combined resisted sprint, and un-resisted sprint on performance in horizontal and vertical 32 jumps, sprint, and change of direction ability in youth soccer players. They have shown that only 33 vertical resisted sprint may promote greater improvements on sprint and changes of direction ability 34 and have a positive additional effect on countermovement jump performance. ...
Article
Ben Brahim, M, Bougatfa, R, Makni, E, Gonzalez, PP, Yasin, H, Tarwneh, R, Moalla, W, and Elloumi, M. Effects of combined strength and resisted sprint training on physical performance in U-19 elite soccer players. J Strength Cond Res XX(X): 000–000, 2020—This study assessed the effects of combined muscular strength and resisted sprint training using both sled and weight vest compared with regular soccer training on physical fitness of lower limbs in U-19 elite soccer players. Thirty-four male soccer players (age: 18.8 ± 0.8 years, height: 1.81 ± 0.05 m, body mass: 76.4 ± 4.9 kg, and body fat mass: 11.3 ± 4.2%) were randomly assigned into a resisted sprint training group (RSTG, n = 20), using both weight vest and sled, and a control group (CONTG, n = 14). Sprinting ability (5 m and 20 m), squat jump (SJ) and counter-movement jump (CMJ) tests, 1 repetition maximum of half-back squat (1RM half-back squat), and soccer ball-shooting speed were assessed before and after a 6-week training program. Within-group interactions showed significant combined muscular strength and resisted sprint training effects were observed for all the tests' measurements (effect sizes = 0.97 and 3.69 for 20-m sprint and SJ, respectively). However, significant increases of performances were observed for 5-m and 20-m sprinting time ( = 0.25, p < 0.01 and = 0.22, p < 0.01, respectively), SJ and CMJ ( = 0.78, p < 0.0001 and = 0.34, p < 0.001, respectively), 1 repetition maximum (1-RM) half-back squat ( = 0.45, p < 0.0001), and soccer ball-shooting speed ( = 0.41, p < 0.0001) in RSTG with large effect size, whereas the CONTG showed significant performances increase only for CMJ (p < 0.05), 1RM half-back squat (p < 0.01), and soccer ball-shooting speed (p < 0.05). We conclude that combined strength and both horizontal (weighted sled) and vertical (weighted vest) resisted sprint training are more effective than regular soccer training for enhancing sprinting and jumping abilities as well as ball-shooting speed in soccer.
... One possible way to do this is via the calculation of differences in VEL between straight sprints and COD maneuvers (ie, COD deficit 16,17 ) or CS of equal distances (ie, CS deficit 19 ). Of note, different cross-sectional 6,15,18 and longitudinal studies [20][21][22] have already investigated the COD and CS deficit in soccer players and found that: (1) faster athletes in linear sprinting actions tend to be less efficient at changing direction and sprinting over curved paths (when considering the slowest test time, as CS test is performed to both right and left sides), 6,15,19 and (2) interventions incorporating COD-specific drills probably reduce the COD deficit in young players. 20,21 Nevertheless, to date, no investigations have simultaneously reported the seasonal variations in CS and COD speed or focused on a similar variable applied to CS actions (ie, the CS deficit) in team sport players. ...
... Of note, different cross-sectional 6,15,18 and longitudinal studies [20][21][22] have already investigated the COD and CS deficit in soccer players and found that: (1) faster athletes in linear sprinting actions tend to be less efficient at changing direction and sprinting over curved paths (when considering the slowest test time, as CS test is performed to both right and left sides), 6,15,19 and (2) interventions incorporating COD-specific drills probably reduce the COD deficit in young players. 20,21 Nevertheless, to date, no investigations have simultaneously reported the seasonal variations in CS and COD speed or focused on a similar variable applied to CS actions (ie, the CS deficit) in team sport players. ...
Purpose: To investigate the effects of a match-congested period on straight and curve sprint performance, change of direction (COD) speed and deficit, vertical jumping ability, and half-squat (HS) mean propulsive power (MPP) output in young soccer players. Methods: A total of 15 under-20 elite male soccer players participated in 14 matches over 8 weeks. The following assessments were performed before and after the congested fixture period: squat and countermovement jumps, 17-m linear sprint, curve sprint test for the "good" (CSGS) and "weak" (CSWS) sides, modified 17-m Zigzag test, and HS MPP. Magnitude-based inferences and a paired t test were used to analyze pre-post changes in the assessed variables. Results: Very likely (P < .05) decreases were noticed in 17-m sprint velocity (effect size [ES] [90% confidence limit; CL], -0.56 [-0.32 to -0.81]) and CSGS (ES [90% CL], -0.72 [-0.40 to 1.03]) after the 8-week period. A possible but nonsignificant impairment was revealed in CSWS (ES [90% CL], -0.18 [0.03 to -0.39]), and countermovement jump (ES [90% CL], -0.21 [-0.54 to 0.12]). Zigzag velocity (ES [90% CL], -2.90 [-2.45 to -3.36]) and COD deficit (ES [90% CL], 0.86 [0.52 to 1.20]) were almost certainly and significantly (P < .05) reduced and increased, respectively, after the match-congested period. An almost certain and significant (P < .05) reduction was found in HS MPP (ES [90% CL], -1.18 [-0.76 to -1.61]). Conclusions: Straight and curve sprint velocity, COD speed and deficit, and HS MPP were impaired after the match-congested period. Vertical jump height was possibly decreased. Seasonal phases comprising high volumes of soccer-specific training and competition seem to be detrimental to speed-power qualities in under-20 elite soccer players.
... More importantly, when looking at the whole image, it appears that when loads are greater than 80% BM or ;50% V dec , substantial impairments in physical, technical, neuromuscular, and physiological factors are expected (7,85,97,126). By contrast, lighter sled loads have shown to be effective to improve sprint performance at least to a similar extent, with considerably less acute negative changes in sprint-related and other performance-related capabilities (6,17,41,96,102). These findings support the notion that light-tomoderate sled loads may be more indicated than heavy or very heavy sled loads to improve top-speed qualities. ...
Article
Sprinting is a key component for many individual and team sports. Therefore, to enhance sprint performance, various training methods are widely used by coaches and practitioners, including maximum sprint speed and resisted sprint training. Resisted sprinting with sled towing is a method that has recently received considerable attention from the sport science community. However, to date, no consensus exists regarding its acute and chronic effects in team sport athletes. This narrative review aimed to (a) review and analyze the mechanics of sprinting under unresisted and resisted conditions with a specific focus on team sport disciplines; (b) provide a thorough and applied discussion on the importance of considering acute and chronic effects of sled loading on technique, electromyographic activity, and force production, as well as on the role of muscle architecture and neural factors in sled training; (c) analyze the effects of increasing sled loads during acceleration and maximum velocity phases on contact and flight phases, while concomitantly examining kinetic, kinematic, and neuromuscular aspects, because all these factors affect each other and cannot be properly understood in isolation.
... [21] The study was conducted according to the Declaration of Helsinki and the protocol was approved by the institutional ethics ES = 0.50) to 'moderate' improvements in maximal sprint velocity (2.4%, ES = 0.80). In strength-trained or team sport individuals, 'Moderate' (10)(11)(12)(13)(14)(15)(16)(17)(18)(19).9%BM) to 'very heavy' (30% BM) sled loads provide 'trivial' to 'extremely large' improvements in acceleration performance (0.5-9.1%, ES = 0.14-4.00). On the other hand, Rumpf et al. [20] showed that this type of training increases velocity via increased step frequency, increased horizontal force and power production. ...
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The purpose of this study was to examine the effects of non-resisted (NRS) and partner-towing resisted (RS) sprint training on legs explosive force, sprint performance and sprint kinematic parameters. Sixteen young elite soccer players (age 16.6 ± 0.2 years, height 175.6 ± 5.7 cm, and body mass 67.6 ± 8.2 kg) were randomly allocated to two training groups: resisted sprint RS (n = 7) and non-resisted sprint NRS (n = 9). The RS group followed a six-week sprint training programme consisting of two "sprint training sessions" per week in addition to their usual soccer training. The NRS group followed a similar sprint training programme, replicating the distances of sprints but without any added resistance. All players were assessed before and after training: vertical and horizontal jumping (countermovement jump (CMJ), squat jump (SJ), and 5-jump test (5JT)), 30 m sprint performance (5, 10, and 20 m split times), and running kinematics (stride length and frequency). In the RS group significant (p < 0.05) changes were: decreased sprint time for 0-5 m, 0-10 m and 0-30 m (-6.31, -5.73 and -2.00%; effect size (ES) = 0.70, 1.00 and 0.41, respectively); higher peak jumping height (4.23% and 3.59%; ES = 0.35 and 0.37, for SJ and CMJ respectively); and 5JT (3.10%; ES = 0.44); and increased stride frequency (3.96%; ES = 0.76). In the NRS group, significant (p < 0.05) changes were: decreased sprint time at 0-30 m (-1.34%, ES = 0.33) and increased stride length (1.21%; ES = 0.17). RS training (partner towing) for six weeks in young soccer players showed more effective performances in sprint, stride frequency and lower-limb explosive force, while NRS training improved sprint performance at 0-30 m and stride length. Consequently, coaches and physical trainers should consider including RS training as part of their sprint training to ensure optimal sprint performance.
... This method consists of finding the difference in the total time of the test minus the linear travel to obtain more accurate results regarding the time taken to perform the sprint, avoiding the interference of linear velocity. Though the agility deficit test was proposed using time, many authors use it with the difference in velocity [22,23]. Considering this, the changes obtained in the PAPE on the T-agility test in this study may have been affected by the participants' improvements in linear velocity, as shown by Chatzopoulos et al. [24], who used loads of 90% of an RM with a 90-degree squat and obtained results showing significant improvements in velocity in 10-and 30-m sprints after PAPE. ...
Article
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This study aimed to compare the effects of the post-activation performance enhancement (PAPE) of two different types of warm-ups, unilateral and bilateral, on the performance in vertical jumping and agility of healthy subjects with strength training experience. In the study, 17 subjects (12 men and 5 women) performed two different PAPE protocols: unilateral squat (UT) and bilateral squat (BT). The height of the subjects’ countermovement jump (CMJ) and the subjects’ time to perform the T-agility test (TAT) were measured before and after executing the PAPE warm-up. The squats were performed at a velocity of 0.59 m·s−1 with three sets of three repetitions, with a 3-min rest between sets and a 5-min rest after both uni- and bilateral PAPE warm-ups before taking the tests again. For statistical analysis, we applied ANOVA and calculated the effect size. The results showed that the PAPE for each case decreased the CMJ height but generated significant improvements in the total time taken for the T-agility test (p < 0.01); however, in both cases, the effect sizes were trivial. In conclusion, it is possible to observe that the PAPE, performed both unilaterally and bilaterally, negatively affects the performance in the vertical jump, showing moderate effect sizes. However, both PAPE protocols show performance benefits in agility tests, with a large effect size for the unilateral protocol and moderate for the bilateral protocol.
... This method consists of finding the difference in the total time of the test minus the linear travel to obtain more accurate results regarding the time taken to perform the sprint, avoiding the interference of linear velocity. Though the agility deficit test was proposed using time, many authors use it with the difference in velocity [22,23]. Considering this, the changes obtained in the PAPE on the T-agility test in this study may have been affected by the participants' improvements in linear velocity, as shown by Chatzopoulos et al., [24], who used loads of 90% of an RM with a 90-degree squat and obtained results showing significant improvements in velocity in 10-and 30-m sprints after PAPE. ...
Article
Full-text available
This study aimed to compare the effects of the post-activation performance enhancement (PAPE) of two different types of warm-ups, unilateral and bilateral, on the performance in vertical jumping and agility of healthy subjects with strength training experience. In the study, 17 subjects (12 men and 5 women) performed two different PAPE protocols: unilateral squat (UT) and bilateral squat (BT). The height of the subjects’ countermovement jump (CMJ) and the subjects’ time to perform the T-agility test (TAT) were measured before and after executing the PAPE warm-up. The squats were performed at a velocity of 0.59 m·s−1 with three sets of three repetitions, with a 3-min rest between sets and a 5-min rest after both uni-and bilateral PAPE warm-ups before taking the tests again. For statistical analysis, we applied ANOVA and calculated the effect size. The results showed that the PAPE for each case decreased the CMJ height but generated significant improvements in the total time taken for the T-agility test (p < 0.01); however, in both cases, the effect sizes were trivial. In conclusion, it is possible to observe that the PAPE, performed both unilaterally and bilaterally, negatively affects the performance in the vertical jump, showing moderate effect sizes. However, both PAPE protocols show performance benefits in agility tests, with a large effect size for the unilateral protocol and moderate for the bilateral protocol.
... When examining the current literature, we can identify 2 different CODD calculations: (a) time-derived (CODDt) (7,8,10,11,20,25,27,36), consisting of the time difference between COD tasks and linear sprints of equivalent distances (e.g., 505 test: CODD 505 5 505 time 2 10-m sprint time); and (b) velocity-derived (CODDv) (3,(12)(13)(14)(21)(22)(23)(24)31), obtained by subtracting the velocities achieved during linear sprints and COD maneuvers of similar distances (e.g., 505 test: CODD 505 5 10-m sprint velocity 2 505 velocity). Nevertheless, to date, it is not clear which measure is more sensitive to assess COD performance. ...
Article
Change of direction (COD) efforts are crucial in team-sports and an extensive body of research has been devoted to investigating this complex and multifaceted skill. Most studies have assessed players' ability to change direction by reporting completion time or average velocity in different COD tasks. However, it has been argued that these variables may not accurately portray an athlete's true capability to quickly change direction. In this context, new metrics such as the "COD Deficit" (CODD) have been proposed to provide complementary information on the efficiency to change direction. The current literature presents two different CODD computations: time-derived and velocity-derived calculations. Despite both being consistent and representing the same phenomenon, the decision of using one or the other may produce different outcomes, thus influencing coaches' decisions and training strategies. To overcome this issue, we propose a new approach to the computation of the CODD, based on the difference in percentage between linear sprint and COD abilities, in an attempt to standardize the estimation of this variable and simplify the evaluation of COD performance.
... The ability to apply and orient a larger quantity of horizontal forces onto the ground influences performance in sprint and COD [14][15][16]. For this reason, and due to their ease of application, horizontal jump tests are frequently included in soccer player testing protocols [17][18][19]. Nonetheless, the relationship between bilateral horizontal jump and sprint performances is somewhat unclear. On one hand, there is evidence of large associations between sprint speed and horizontal jump distances in soccer players [17,20]. ...
Article
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The aim of this study was to examine the associations between linear sprint, curve sprint (CS), change of direction (COD) speed, and jump performance in a sample of 17 professional female soccer players. All athletes performed squat and countermovement jumps, single leg horizontal triple jumps, 17-m linear sprint and CS test, and a 17-m Zigzag COD test. A Pearson product moment test was performed to determine the relationships among the assessed variables. Significance level was set at P< 0.05. Nearly perfect associations (r> 0.9) were found between linear and CS velocities. Faster players in linear sprints and CS exhibited greater COD deficits. No significant associations between COD deficit and body mass or sprint momentum were found. Jumping ability was significantly correlated to linear sprint and CS, but not to COD performance. These findings may be used by coaches and practitioners to guide testing and training prescription in this population. The associations observed here suggest that training methods designed to improve linear sprint and CS velocities may benefit from the implementation of vertically- and horizontally-oriented plyometric exercises.
... adding to the previous information, the significant association found between cod and cS velocities might imply that the prescription of cod-oriented drills (i.e. exercises that require greater application of mediolateral ground reaction forces or involve superior levels of trunk stabilization) 26,28,35 are suitable options to improve both cod and cS abilities. undoubtedly, these hypotheses need to be further examined as this was the first study to simultaneously investigate sprint, cod, and cS performances in team-sport athletes. ...
Article
Background: The aim of this study was to investigate the relationships between linear sprint, curve sprint (CS), and change of direction (COD) abilities and vertical jump performance in elite young soccer players. Methods: Twenty-nine players from the same soccer club participated in this study. On the same day, athletes performed countermovement jump (CMJ), 17-m linear sprint (with a 10-m split time), CS (for both sides), and COD tests. A Pearson product moment correlation was performed to determine the associations between the assessed variables. Significance level was set at P< 0.05. Results: Linear sprint was significantly related to CS (r ranging from 0.67 and 0.76; P< 0.05) but not to COD performance (r = 0.23 and 0.33 for 10- and 17-m, respectively; P> 0.05). CS ability (for both good and weak sides) was significantly associated with COD performance (r = 0.60 and 0.54, respectively; P< 0.05). CMJ height was significantly correlated with both linear and CS velocities (r varying between 0.50 and 0.68; P< 0.05), but not with COD velocity (r =0.37; P> 0.05). Conclusions: Based on these findings, it is possible to suggest that training strategies designed to improve vertical jumping capacity may potentially improve both linear and curvilinear sprint abilities. Moreover, increases in COD velocity may also produce positive changes in CS performance.
Article
Fernández-Galván, LM, Casado, A, García-Ramos, A, and Haff, GG. Effects of vest and sled resisted sprint training on sprint performance in young soccer players: A systematic review and meta-analysis. J Strength Cond Res XX(X): 000-000, 2022-The aim of the meta-analysis was to determine the effect of resisted sprint training (RST) on sprint performance in young (<20 years) soccer players and to analyze whether the training equipment (sled or vest) and magnitude of the resistive load (above or below 20% of body mass [BM]) influences the long-term adaptations in sprint performance. Resisted sprint training reduced the acceleration phase time [standardized mean difference (SMD) = -0.41], with greater reduction in sprint time occurring in response to applying resistance with a vest (SMD = -0.70) when compared with a sled (SMD = -0.27). Similar reductions were determined for resistive loads <20% (SMD = -0.55) and ≥20% of BM (SMD = -0.31). Full sprint time showed a small reduction after RST (SMD = -0.36), regardless of the training equipment (sled: SMD = -0.44; vest: SMD = -0.26) and resistive load (<20% of BM: SMD = -0.40 ≥ 20% of BM: SMD = -0.21). There was a small and nonsignificant reduction in the maximum-velocity phase after RST (SMD = -0.25), which was comparable when the training was performed with vest (SMD = -0.34) or sled (SMD = -0.22). No significant differences in the changes of the acceleration phase time (SMD = 0.05) or full sprint time (SMD = 0.08) were observed between the experimental (sled or vest RST) and control groups (only soccer or unresisted sprint training). In conclusion, RST is effective to improve sprint performance in young soccer players, but the improvements are not superior to unresisted sprint training.
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zet Günümüz futbolunda futbolcuların sık sık mevki değiştirdikleri ve bu mevki değişimleri sırasında tekrarlı sprintleri sıklıkla uygulaması gerektiği görülmektedir. Tekrarlı sprintlerin futbolda sıklıkla uygulanması gerekmesi, futbolda aerobik gücün yanında anaerobik kapasitenin de önemini arttırmaktadır. Bu araştırmanın amacı, tekrarlı sprint derecelerinin aerobik güç ile ilişkisinin incelenmesidir. Çalışmaya, Ankara'da ve Antalya'da, profesyonel futbol takımlarının alt kategorilerinde mücadele eden, 15-18 yaş grubundan 97 futbolcu dahil edilmiştir. Oyuncuların demografik özellikleri kaydedilmiştir. Futbolculara Yo-Yo testi ve tekrarlı (intermittent) sprint testi uygulanmıştır. Verilerin analizi için Pearson Çarpımlar Momenti Korelasyonu Testi ve mevkiler arası farklar için One-Way ANOVA Testi uygulanmış ve 0.05 hata ile karşılaştırılmıştır. Analiz sonucunda maxVO2 değeri yüksek olan sporcuların tekrarlı sprint yorgunluk indeksi değerleri daha düşük olduğu görülmüştür. Sprint zamanları toplamı düşük olan sporcuların maxVO2 değerlerinin yüksek olduğu kaydedilmiştir ancak ilişki katsayısı (r =-0.273) düşüktür. Sprint zamanları toplamı değerleri, başarılı olandan başlanarak mevkilere göre sıralandığında; forvet, orta saha, defans ve kaleci şeklindedir. Yorgunluk değerlerine göre sıralandığında ise; orta saha, defans, forvet, kaleci şeklinde bulunmuştur. Aerobik gücün yüksek olmasının, sporcuların tekrarlı sprint performansını olumlu yönde etkilediği kaydedilmiştir. Elde edilen verilere göre, aerobik güç seviyesi yüksek olan sporcuların sprint için ihtiyaç duyulan acil enerji kaynağı olan ATP-CP'yi daha çabuk yerine koyabildiği düşünülebilir. Futbol antrenmanlarında, tekrarlı sprintlerin yanında, aerobik güç antrenmanlarına da yer verilmesi futbolcuların performansının arttırılması için önemli olabilir. Ayrıca bazı mevkilerdeki sporcuların maxVO2 değerleri takım içerisindeki diğer sporculara göre düşük bulunmuştur. maxVO2 değerleri düşük olan sporcuların yorgunluk indeksi değerleri de performans açısından daha düşük değerde bulunmuştur. Aerobik dayanıklılık antrenmanlarının mevkilere göre tasarlanarak uygulanması, takımdaki tüm mevkiler için performansı olumlu yönde etkileyebilir. Abstract In today's football, it is seen that footballers change positions frequently therefore they should apply repeated sprints frequently during these positions changes. Intermittent sprints need to be applied frequently in football, increasing the importance of anaerobic capacity as well as aerobic power in football. The purpose of this study was to investigate the relationship between intermittent sprint degrees and aerobic power. 97 footballers aged between 15-18 who are competing in the infrastructure of professional football teams from Ankara and Antalya were included in the research. The demographic characteristics of the players were recorded. Yo-Yo test and repeat (intermittent) sprint test were applied to football players. Pearson Product Moment Correlation Test for data analysis and One-Way ANOVA Test for differences between sites were compared with 0.05 error. As a result of the analysis, it was seen that the athletes with high maxVO2 value had lower sprint fatigue index values. It has been noted that the athletes with low sprint times have a high maxVO2 value, but the correlation coefficient (r =-0.273) is low. When the sprint time sum values are listed starting from the successful ones in terms of positions, they are in the form of striker, midfielder, defender and goalkeeper. It was found as midfield, defender, striker, and goalkeeper when ranked by fatigue values. The high aerobic power positively affects the athlete's intermittent sprint performance. According to the data obtained, it can be thought that athletes with high aerobic power can replace ATP-CP needed for sprinting more quickly. It is recommended for the performance of football players that it includes aerobic power training in addition to intermittent type sprints in football training. In addition, the maxVO2 values of the athletes in some positions were found lower than the other athletes in the team. The fatigue index values of athletes with low maxVO2 values were also lower in terms of performance. The application of aerobic endurance training adapted to the positions can positively affect the performance for all positions in the team. SUMMARY Introduction: Football is among the most popular branches in Turkey and all over the World today and is in the limelight of millions of people. Along with the technological and scientific developments, there have been important changes in the game of football and with it, football has become a high-pace, endurance and high coordination competition played under the pressure of field and time. It is known that endurance, strength, speed, coordination and flexibility should be a good combination of basic motor skills for successful performance in football. In a football competition, the distance covered by movements requiring aerobic endurance accounts for 78.5% of the entire competition, while movements that require anaerobic power and capacity make up 18.8%. While determining the general aerobic endurance level of a football player, properties such as maxVO2, anaerobic threshold, maximum lactate level and resting efficiency are measured. In addition to aerobic endurance, the importance of anaerobic features is also important in football, especially short and long distance sprints. It is noted that in current football, football players frequently change positions and use sprints a lot during these position changes. All of the energy systems are active in football players. It is known that the energy system, which is mobilized at the beginning of the severe exercise or among the short-term efforts up to 8 seconds, is the ATP-CP system, and the glycolytic system is dominant during the efforts that continue for a maximum of 8-30 seconds. For this reason, tests that can provide information about all energy systems are required in today's football. Aim: In this study, the relationship between the repetitive (intermittent) sprint rank Sportif Bakış: Spor ve Eğitim Bilimleri Dergisi, 7(2): 93-102, 2020
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This study assessed the validity of 5-m (TG5) and 10-m (TG10) split times measured with timing gates to estimate maximum sprint speed (MSS) against a criterion measure radar gun (RG) during the maximum velocity phase of a 30-m sprint. Nineteen amateur rugby players performed two 30-m sprints. The timing gates were placed at the starting line and at 5-, 10-, 20-, 25- and 30-m. In addition, a RG was used to measure instantaneous velocity. Both trials per participant were used selected as references. MSS obtained from TG10, TG5 and RG showed high intraclass correlation coefficients (0.971-0.978), low coefficients of variation (1.14-1.70%) and smallest detectable changes (< 0.02 m/s). Pairwise comparison revealed differences (p = 0.002) in MSS when comparing TG10 to RG, but not TG5 and RG (p = 0.957). Almost perfect correlations were found between RG, TG5 and TG10 (r > 0.926, p < 0.001). In conclusion, MSS obtained from TG5, TG10 and RG presented good intra-session reliability. However, practitioners should be aware that substantial differences exist between TG10 and RG. For the assessment of MSS in team-sport athletes, it is recommended the use of TG5 for more accurate estimations when a gold standard criterion is not available.
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Purpose: Resisted sled sprinting (RSS) is an effective tool for improving sprint performance over short distances, but the effect on change-of-direction (COD) performance is largely unknown. The present study investigated the effect of heavy RSS training during the competitive season on sprint and COD performance in professional soccer players. Methods: Over six weeks in-season, a RSS training group (n=6) performed RSS at a sled load of 30% of body mass for a total programme running distance of 800 m, while an unresisted sprint (URS) training group (n=7) performed the same distance of unresisted sprinting. A 20 m maximal sprint with split times measured at 5, 10 and 20 m, and the sprint 9-3-6-3-9 m with 180° turns COD test were performed before and after the intervention. Results: Sprint performance (mean; 95% confidence limits; qualitative inference) was improved in both groups over 5 m (URS, 5.1%; -2.4, 12.7; likely moderate; RSS, 5.4%; 0.5, 10.4; likely moderate), 10 m (URS, 3.9%; -0.3, 8.1; very likely moderate; RSS, 5.0%; 1.8, 8.0; very likely large), and 20 m (URS, 2.0%; -0.6, 4.5; likely moderate; RSS (3.0%; 1.7, 4.4; very likely moderate). COD was improved in both groups (URS, 3.7%; 2.2, 5.2; most likely large; RSS, 3.3%; 1.6, 5.0; most likely moderate). Between-group differences were unclear. Conclusions: Heavy RSS or URS training matched for running distance were similarly effective at improving sprint and COD performance in professional soccer players when performed in the competitive phase of the season.
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The capacity to rapidly generate and apply a great amount of force seems to play a key role in sprint running. However, it has recently been shown that, for sprinters, the technical ability to effectively orient the force onto the ground is more important than its total amount. The force-vector theory has been proposed to guide coaches in selecting the most adequate exercises to comprehensively develop the neuromechanical qualities related to the distinct phases of sprinting. This study aimed to compare the relationships between vertically-directed (loaded and unloaded vertical jumps, and half-squat) and horizontally-directed (hip-thrust) exercises and the sprint performance of top-level track and field athletes. Sixteen sprinters and jumpers (including three Olympic athletes) executed vertical jumps, loaded jump squats and hip-thrusts, and sprinting speed tests at 10-, 20-, 40-, 60-, 100-, and 150-m. Results indicated that the hip-thrust is more associated with the maximum acceleration phase (i.e., from zero to 10-m; r = 0.93), whereas the loaded and unloaded vertical jumps seem to be more related to top-speed phases (i.e., distances superior to 40-m; r varying from 0.88 to 0.96). These findings reinforce the mechanical concepts supporting the force-vector theory, and provide coaches and sport scientists with valuable information about the potential use and benefits of using vertically- or horizontally-based training exercises.
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Background: Sprinting is key in the development and final results of competitions in a range of sport disciplines, both individual (e.g., athletics) and team sports. Resisted sled training (RST) might provide an effective training method to improve sprinting, in both the acceleration and the maximum-velocity phases. However, substantial discrepancies exist in the literature regarding the influence of training status and sled load prescription in relation to the specific components of sprint performance to be developed and the phase of sprint. Objectives: Our objectives were to review the state of the current literature on intervention studies that have analyzed the effects of RST on sprint performance in both the acceleration and the maximum-velocity phases in healthy athletes and to establish which RST load characteristics produce the largest improvements in sprint performance. Methods: We performed a literature search in PubMed, SPORTDiscus, and Web of Science up to and including 9 January 2018. Peer-reviewed studies were included if they met all the following eligibility criteria: (1) published in a scientific journal; (2) original experimental and longitudinal study; (3) participants were at least recreationally active and towed or pulled the sled while running at maximum intensity; (4) RST was one of the main training methods used; (5) studies identified the load of the sled, distance covered, and sprint time and/or sprint velocity for both baseline and post-training results; (6) sprint performance was measured using timing gates, radar gun, or stopwatch; (7) published in the English language; and (8) had a quality assessment score > 6 points. Results: A total of 2376 articles were found. After filtering procedures, only 13 studies were included in this meta-analysis. In the included studies, 32 RST groups and 15 control groups were analyzed for sprint time in the different phases and full sprint. Significant improvements were found between baseline and post-training in sprint performance in the acceleration phase (effect size [ES] 0.61; p = 0.0001; standardized mean difference [SMD] 0.57; 95% confidence interval [CI] - 0.85 to - 0.28) and full sprint (ES 0.36; p = 0.009; SMD 0.38; 95% CI - 0.67 to - 0.10). However, non-significant improvements were observed between pre- and post-test in sprint time in the maximum-velocity phase (ES 0.27; p = 0.25; SMD 0.18; 95% CI - 0.49 to 0.13). Furthermore, studies that included a control group found a non-significant improvement in participants in the RST group compared with the control group, independent of the analyzed phase. Conclusions: RST is an effective method to improve sprint performance, specifically in the early acceleration phase. However, it cannot be said that this method is more effective than the same training without overload. The effect of RST is greatest in recreationally active or trained men who practice team sports such as football or rugby. Moreover, the intensity (load) is not a determinant of sprint performance improvement, but the recommended volume is > 160 m per session, and approximately 2680 m per week, with a training frequency of two to three times per week, for at least 6 weeks. Finally, rigid surfaces appear to enhance the effect of RST on sprint performance.
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Resisted sprint training consists of performing overloaded sprints, which may produce greater effects than traditional sprint training. We compared a resisted sprint training with overload control versus an unresisted sprint training program on performance in soccer players. Eighteen elite athletes were randomly assigned to resisted (RST) or unresisted sprint training protocol (UR). Before and after a 6-week training period, sprinting ability, change of direction speed (COD), vertical jumps (SJ and CMJ), mean power (MP) and mean propulsive power (MPP) at distinct loads were assessed. Both groups improved sprinting ability at all distances evaluated (5m: UR = 8%, RST = 7%; 10m: UR = 5%, RST = 5%; 15m: UR = 4%, RST = 4%; 20m: UR = 3%, RST = 3%; 25m: UR = 2%, RST = 3%;), COD (UR = 6%; RST = 6%), SJ (UR = 15%; RST = 13%) and CMJ (UR = 15%; RST = 15%). Additionally, both groups increased MP and MPP at all loads evaluated. The between-group magnitude-based inference analysis demonstrated comparable improvement ("trivial" effect) in all variables tested. Finally, our findings support the effectiveness of a short-term training program involving squat jump exercise plus sprinting exercises to improve the performance of soccer players.
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This study aimed to assess the chronic effects of vertical and horizontal drop-jumpbased protocols on neuromuscular explosive abilities such as jumping, sprinting, and change of direction (COD). Eighteen elite male handball players (age 23.4 ± 4.6 years; height 192.5 ± 3.7 cm; weight 87.8 ± 7.4 kg) were assigned to either vertical drop jump (VDJ) or horizontal drop jump (HDJ) group training twice a week for 10 weeks. Participants performed 5-8 sets × 6-10 repetitions of vertical-alternate (VDJ) or horizontal-alternate (HDJ) one-leg drop-jumps, landing from the top of a platform 25 cm in height. Before and after training, several performance, kinetic and kinematic variables were assessed. The HDJ led to greater improvement of the sprint-time (- 8.5% vs. -4%; p<0.05) and COD performance in comparison with the VDJ (-7.9% vs. - 1.1%; p<0.05), while the VDJ caused greater improvement in the vertical jump compared with the HDJ (+8.6% vs. +4.1%; p<0.05). Moreover, the VDJ regimen compared with the HDJ, induced greater changes in the kinetic variables associated with vertical jumping performance, such as peak ground reaction forces (+10.3% vs. +4.3%), relative impulse (+12.4% vs. +5.7%), leg-spring stiffness (+17.6% vs. +4.6%), contact time (-10.1% vs. -1.5%), and reactive strength index (+7.2% vs. +2.1%); all comparisons with p<0.05. Conversely, the HDJ regimen was able to improve the shortdistance and COD performances by increasing the step length (+3.5% vs. +1.5% with p<0.05) and reducing the contact time on COD (-12.1% vs. -2.1% with p<0.05) more than the VDJ. This investigation showed the crucial role that specific plyometric regimens play in optimizing similar biomechanical featured functional performances such as jumping, sprinting and COD.
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This review article discusses previous literature that has examined the influence of muscular strength on various factors associated with athletic performance and the benefits of achieving greater muscular strength. Greater muscular strength is strongly associated with improved force-time characteristics that contribute to an athlete’s overall performance. Much research supports the notion that greater muscular strength can enhance the ability to perform general sport skills such as jumping, sprinting, and change of direction tasks. Further research indicates that stronger athletes produce superior performances during sport specific tasks. Greater muscular strength allows an individual to potentiate earlier and to a greater extent, but also decreases the risk of injury. Sport scientists and practitioners may monitor an individual’s strength characteristics using isometric, dynamic, and reactive strength tests and variables. Relative strength may be classified into strength deficit, strength association, or strength reserve phases. The phase an individual falls into may directly affect their level of performance or training emphasis. Based on the extant literature, it appears that there may be no substitute for greater muscular strength when it comes to improving an individual’s performance across a wide range of both general and sport specific skills while simultaneously reducing their risk of injury when performing these skills. Therefore, sport scientists and practitioners should implement long-term training strategies that promote the greatest muscular strength within the required context of each sport/event. Future research should examine how force-time characteristics, general and specific sport skills, potentiation ability, and injury rates change as individuals transition from certain standards or the suggested phases of strength to another.
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Recent studies have brought new insights into the evaluation of power-force-velocity profiles in both ballistic push-offs (e.g. jumps) and sprint movements. These are major physical components of performance in many sports, and the methods we developed and validated are based on data that are now rather simple to obtain in field conditions (e.g. body mass, jump height, sprint times or velocity). The promising aspect of these approaches is that they allow for a more individualized and accurate evaluation, monitoring, and training practices; the success of which are highly dependent on the correct collection, generation and interpretation of athletes' mechanical outputs. We therefore wanted to provide a practical vade mecum to sports practitioners interested in implementing these power-force-velocity profiling approaches. After providing a summary of theoretical and practical definitions for the main variables, we have first detailed how vertical profiling can be used to manage ballistic push-off performance with emphasis on the concept of optimal force-velocity profile and the associated force-velocity imbalance. Further, we have discussed these same concepts with regards to horizontal profiling in the management of sprinting performance. These sections have been illustrated by typical examples from our own practice. Finally, we have provided a practical and operational synthesis, and outlined future challenges that will help in further developing these approaches.
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The objective of this study was to characterize the mechanics of maximal running sprint acceleration in high-level athletes. Four elite (100-m best time 9.95–10.29 s) and five sub-elite (10.40–10.60 s) sprinters performed seven sprints in overground conditions. A single virtual 40-m sprint was reconstructed and kinetics parameters were calculated for each step using a force platform system and video analyses. Anteroposterior force (FY), power (PY), and the ratio of the horizontal force component to the resultant (total) force (RF, which reflects the orientation of the resultant ground reaction force for each support phase) were computed as a function of velocity (V). FY-V, RF-V, and PY-V relationships were well described by significant linear (mean R2 of 0.892 ± 0.049 and 0.950 ± 0.023) and quadratic (mean R2 = 0.732 ± 0.114) models, respectively. The current study allows a better understanding of the mechanics of the sprint acceleration notably by modeling the relationships between the forward velocity and the main mechanical key variables of the sprint. As these findings partly concern world-class sprinters tested in overground conditions, they give new insights into some aspects of the biomechanical limits of human locomotion.
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Purpose: The purpose of this study was to examine the concurrent and construct validity of the Borg (0-10) and children's OMNI scales for quantifying the exercise intensity and training load (TL) in youth soccer players. Methods: Twelve children (mean ± SD age 11.4 ± 0.5 y, height 154.3 ± 6.5 cm, body mass 39.5 ± 5.4 kg) took part in this study. Exercise intensity and TL were calculated on the basis of the session rating of perceived exertion (sRPE) and heart rate (HR; Edwards method) during 20 technical-tactical training sessions. Players' sRPEs were obtained from the Borg and OMNI scales. Results: Low correlations between HR-based TL and sRPE TL based on the Borg (r = .17, P = .335) and OMNI (r = .34, P = .007) scales were obtained. Significant (P < .001) relationships in sRPE (r = .76) and TL (r = .79) between RPE scales were found. Conclusion: The current data do not support the relationship between the sRPE and HR methods for quantifying TL in youth soccer players. However, the sRPE method could be considered a better indicator of global internal TL, since sRPE is a measure of both physical and psychological stress. In addition, the authors demonstrated the construct validity for the OMNI scale to control exercise demands.
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The overall objective of this review was to investigate the role and development of sprinting speed in soccer. Time motion analyses show that short sprints occur frequently during soccer games. Straight sprinting is the most frequent action prior to goals, both for the scoring and assisting player. Straight line sprinting velocity (both acceleration and maximal sprinting speed), certain agility skills and repeated sprint ability are shown to distinguish groups from different performance levels. Professional players have become faster over time, indicating that sprinting skills are becoming more and more important in modern soccer. In research literature, the majority of soccer related training interventions have provided positive effects on sprinting capabilities, leading to the assumption that all kinds of training can be performed with success. However, most successful intervention studies are time consuming and challenging to incorporate into the overall soccer training program. Even though the principle of specificity is clearly present, several questions remain regarding the optimal training methods within the larger context of the team sport setting. Considering time-efficiency effects, soccer players may benefit more by performing sprint training regimes similar to the progression model used in strength training and by world leading athletics practitioners, compared to the majority of guidelines that traditionally have been presented in research literature.
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Purpose: This study describes the physical match demands relative to positional group in male rugby sevens. Methods: Ten highly trained players were investigated during competitive matches (N = 23) using GPS technology, heart rate (HR), and video recording. Results: The relative distance covered by the players throughout the match was 102.3 ± 9.8 m/min. As a percentage of total distance, 35.8% (36.6 ± 5.9 m/min) was covered walking, 26.0% (26.6 ± 5.5 m/min) jogging, 10.0% (10.2 ± 2.4 m/min) running at low intensity, 14.2% (14.5 ± 4.0 m/min) at medium intensity, 4.6% (4.7 ± 1.6 m/min) at high intensity, and 9.5% (9.7 ± 3.7 m/min) sprinting. For the backs, a substantial decrease in total distance and distance covered at low, medium, and high intensity was observed in the second half. Forwards exhibited a substantial decrease in the distance covered at medium intensity, high intensity, and sprinting in the 2nd half. Backs covered substantially more total distance at medium and sprinting speeds than forwards. In addition, the maximum length of sprint runs was substantially greater for the backs than forwards. On the contrary, forwards performed more tackles. The mean HR during the match in backs and forwards was similar, with the exception of time spent at HR intensities >90%HRmax, which was substantially higher in forwards. Conclusion: These findings provide a description of the different physical demands placed on rugby sevens backs and forwards. This information may be helpful in the development of positional and/or individualized physical-fitness training programs.
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Purpose: The aim of this study was to compare the effects of 2 strength and conditioning programs involving either purely vertically oriented or combining vertically and horizontally oriented exercises on soccer-relevant performance variables (ie, acceleration, jumping ability, peak power, and endurance). Methods: Twenty-two professional male soccer players were randomly assigned to 2 training groups: vertical strength (VS, n = 11) and vertical and horizontal strength (VHS, n = 11). Players trained 2 times per week during all the preseason (5 wk) and 3 weeks of the competitive season. The effect of the training protocols was assessed using double-and single-leg vertical countermovement jumps (CMJ), half-squat peak power (PP), sprint performance over 5 and 15 m, and blood lactate concentration at selected running speeds. Results: Both groups obtained significant improvements in PP (P < .05; ES = 0.87 and 0.80 for VS and VHS, respectively) and small practical improvements in 5-m- (P < .05; ES = 0.27 and 0.25 for VS and VHS, respectively) and 15-m-sprint time (P < .05; ES = 0.19 and 0.24 for VS and VHS, respectively). The CMJ performance showed a small improvement (P < .05, ES = 0.34) only in the VHS group. Submaximal aerobic-fitness changes were similar in both groups (P < .05; ES = 1.89 and 0 .71 for VS and VHS, respectively). Conclusion: This study provided a small amount of practical evidence for the consideration of preseason training protocols that combine exercises for vertical- and horizontal-axis strength development in professional male soccer players. Further studies using more aggressive training protocols involving horizontally oriented conditioning exercises are warranted.
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Purpose: The aim of this study was to compare the effects of two strength and conditioning programs involving either purely vertically oriented or combining vertically and horizontally oriented exercises on soccer relevant performance variables (i.e. acceleration, jumping ability, peak power, and endurance). Methods: Twenty-two professional male soccer players were randomly assigned to two training groups: vertical strength (VS, n=11) and vertical and horizontal strength (VHS, n=11). Players trained 2 times per week during all the pre-season (5 weeks) and 3 weeks of the competitive season. The effect of the training protocols was assessed using double and single leg vertical countermovement jumps (i.e. CMJ, CMJ-SL respectively), half-squat peak power (PP), sprint performance over 5 and 15 m and blood lactate concentration at selected running speeds. Results: Both groups obtained significant improvements in PP (P<.05. ES= .87 and .80 for VS and VHS, respectively) and small practical improvements in 5 m (P<.05. ES= .27 and .25 for VS and VHS, respectively) and 15 m sprint time (P<.05. ES= .19 and .24 for VS and VHS, respectively). The CMJ performance showed a small improvement (P<.05, ES= 0.34) only in the VHS group. Sub maximal aerobic-fitness changes were similar in both groups (P<.05. ES= 1.89 and .71 for VS and VHS, respectively). Conclusion: This study provided a small amount of practical evidence for the consideration of pre-season training protocols that combine exercises for vertical and horizontal axis strength development in professional male soccer players. Further studies using more aggressive training protocols involving horizontally-oriented conditioning exercises are warranted.
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Purpose: To compare sprint and countermovement-jump (CMJ) performance among competitive soccer players as a function of performance level, field position, and age. In addition, the authors wanted to quantify the evolution of these physical characteristics among professional players over a 15-y period. Methods: 939 athletes (22.1 ± 4.3 y), including national-team players, tested 40-m sprint with electronic timing and CMJ on a force platform at the Norwegian Olympic Training Center between 1995 and 2010. Results: National-team and 1st-division players were faster (P < .05) than 2nd-division (1.0-1.4%), 3rd- to 5th-division (3.0-3.8%), junior national-team (1.7-2.2%), and junior players (2.8-3.7%). Forwards were faster than defenders (1.4%), midfielders (2.5%), and goalkeepers (3.2%) over 0-20 m (P < .001). Midfielders jumped ~2.0 cm lower than the other playing positions (P < .05). Sprinting velocity peaked in the age range 20-28 y and declined significantly thereafter (P < .05). Players from 2006-2010 had 1-2% faster 0-20 m and peak velocity than players from the 1995-1999 and 2000-2005 epochs, whereas no differences in CMJ performance were observed. Conclusions: This study provides effect-magnitude estimates for the influence of performance level, position, and age on sprint and CMJ performance in soccer. While CMJ performance has remained stable over the time, there has been a small but positive development in sprinting velocity among professional players.
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The ability to change direction while sprinting is considered essential for successful participation in most team and individual sports. It has traditionally been thought that strength and power development would enhance change of direction (COD) performance. The most common approach to quantifying these relationships, and to discovering determinants (physiological and mechanical) of COD performance, is with correlation analysis. There have not been any strength or power variables that significantly correlated with COD performance on a consistent basis and the magnitude of the correlations were, for the most part, small to moderate. The training studies in the literature that have utilized traditional strength and power training programmes, which involved exercises being performed bilaterally in the vertical direction (e.g. Olympic-style lifts, squats, deadlifts, plyometrics, vertical jumping), have mostly failed to elicit improvements in COD performance. Conversely, the training protocols reporting improvements in COD performance have utilized exercises that more closely mimic the demands of a COD, which include horizontal jump training (unilateral and bilateral), lateral jump training (unilateral and bilateral), loaded vertical jump training, sport-specific COD training and general COD training.
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Sprint mechanics and field 100-m performances were tested in 13 subjects including 9 non-specialists, 3 French national-level sprinters and a world-class sprinter, to further study the mechanical factors associated with sprint performance. 6-s sprints performed on an instrumented treadmill allowed continuous recording of step kinematics, ground reaction forces (GRF), and belt velocity and computation of mechanical power output and linear force-velocity relationships. An index of the force application technique was computed as the slope of the linear relationship between the decrease in the ratio of horizontal-to-resultant GRF and the increase in velocity. Mechanical power output was positively correlated to mean 100-m speed (P < 0.01), as was the theoretical maximal velocity production capability (P < 0.011), whereas the theoretical maximal force production capability was not. The ability to apply the resultant force backward during acceleration was positively correlated to 100-m performance (r (s) > 0.683; P < 0.018), but the magnitude of resultant force was not (P = 0.16). Step frequency, contact and swing time were significantly correlated to acceleration and 100-m performance (positively for the former, negatively for the two latter, all P < 0.05), whereas aerial time and step length were not (all P > 0.21). Last, anthropometric data of body mass index and lower-limb-to-height ratio showed no significant correlation with 100-m performance. We concluded that the main mechanical determinants of 100-m performance were (1) a "velocity-oriented" force-velocity profile, likely explained by (2) a higher ability to apply the resultant GRF vector with a forward orientation over the acceleration, and (3) a higher step frequency resulting from a shorter contact time.
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The ability to change direction while sprinting is considered essential for successful participation in most team and individual sports. It has traditionally been thought that strength and power development would enhance change of direction (COD) performance. The most common approach to quantifying these relationships, and to discovering determinants (physiological and mechanical) of COD performance, is with correlation analysis. There have not been any strength or power variables that significantly correlated with COD performance on a consistent basis and the magnitude of the correlations were, for the most part, small to moderate. The training studies in the literature that have utilized traditional strength and power training programmes, which involved exercises being performed bilaterally in the vertical direction (e.g. Olympic-style lifts, squats, deadlifts, plyometrics, vertical jumping), have mostly failed to elicit improvements in COD performance. Conversely, the training protocols reporting improvements in COD performance have utilized exercises that more closely mimic the demands of a COD, which include horizontal jump training (unilateral and bilateral), lateral jump training (unilateral and bilateral), loaded vertical jump training, sport-specific COD training and general COD training.
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In this study, we compared sprint kinematics of sled towing and vest sprinting with the same relative loads. Twenty athletes performed 30-m sprints in three different conditions: (a) un-resisted, (b) sled towing, and (c) vest sprinting. During sled towing and vest sprinting, external loads of 15% and 20% of body mass were used. Sprint times were recorded over 10 and 30 m. Sagittal-plane high-speed video data were recorded at 5, 15, and 25 m from the start. Relative to the un-resisted condition, sprint time increased (7.5 to 19.8%) in both resisted conditions, resulting mainly from decreased step length (-5.2 to -16.5%) with small decreases in step frequency (-2.7 to -6.1%). Sled towing increased stance phase duration (14.7 to 26.0%), trunk angle (12.5 to 71.5%), and knee angle (10.3 to 22.7%), and decreased swing phase duration (-4.8 to -15.2%) relative to the un-resisted condition. Vest sprinting increased stance phase duration (12.8 to 24.5%) and decreased swing phase duration (-8.4 to -14.4%) and trunk angle (-1.7 to -13.0%). There were significant differences between the two resisted conditions in trunk, thigh, and knee angles. We conclude that sled towing and vest sprinting have different effects on some kinematics and hence change the overload experienced by muscle groups.
Article
Purpose: To compare the effects of resisted change-of-direction (COD) movements, using several relative loads, on soccer players' physical performance. Methods: Fifty-four male soccer players were randomly assigned to 1 of the following 3 groups, which differed only in the magnitude of the external load used during the COD training: COD training without external load (COD-0; n = 16), COD training with a 12.5% body-mass external load (COD-12.5; n = 19), and COD training with a 50% body-mass external load (COD-50; n = 19). Participants performed the specific COD training twice per week for 6 wk. Before and after the training period, a battery of tests was completed: countermovement jump, 30-m running sprint (time in 10 m [T10], 20 m [T20], and 30 m [T30]), L-run test, and V-cut test. Results: Within-group comparisons showed substantial improvements in countermovement jump and T10 (likely) in COD-0, whereas countermovement jump, T10, and T20 were substantially enhanced (possibly to likely) in COD-50. COD-12.5 induced substantial improvements in all analyzed variables (likely to most likely). Between-groups comparisons showed better effects on all analyzed variables for COD-12.5 than for COD-0 (possibly to very likely), whereas COD-50 only showed possibly better effects than COD-0 on T10. In addition, COD-12.5 induced a better effect on L-run and V-cut tests than COD-50 (possibly to likely). Conclusions: These results indicate that COD training, especially moderate load (12.5% body mass) resisted COD training, may have a positive effect on COD skills, running sprint performance, and jumping ability in young soccer players.
Article
Purpose:: To describe the load-velocity relationship and the effects of increasing loads on spatio-temporal and derived kinetics variables of sprinting using weighted vest (WV) in soccer players and determining the load that maximized power output. Methods:: Twenty-three soccer players (age: 20.8±1.5 years) performed ten maximal 30-m sprints wearing a WV, with five different loads (0, 10, 20, 30 and 40% body mass (BM). Sprint velocity and time were collected using a radar device and wireless photocells. Mechanical outputs were computed using a recently developed valid and reliable field method that estimates the step-averaged ground reaction forces (GRF) during over ground sprint acceleration from anthropometric and spatio-temporal data. Raw velocity-time data were fitted by an exponential function and used to calculate the net horizontal GRF and horizontal power output. Individual linear force-velocity relationships were then extrapolated to calculate the theoretical maximum horizontal force (F0) and velocity, and the ratio of force application (RF: proportion of the total force production that is directed forward at sprint start). Results:: Magnitude-based inferences showed an almost certain decrease on F0 (effect size [ES]=0.78-3.35), maximum power output (ES=0.78-3.81), and maximum ratio of force (ES=0.82-3.87) as the load increased. The greatest changes occurred with loads heavier than 20% BM, especially in RF. Additionally, the maximum power was achieved under unloaded condition. Conclusions:: Increasing load on WV sprinting affects the spatio-temporal and kinetic variables. The greatest change in RF happened with loads heavier than 20% BM. Thus, we recommend the use of loads ≤20% BM for WV sprinting.
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The quantification of mechanical power can provide valuable insight into athlete performance because it is the mechanical principle of the rate at which the athlete does work or transfers energy to complete a movement task. Estimates of power are usually limited by the capabilities of measurement systems, resulting in the use of simplified power models. This review provides a systematic overview of the studies on mechanical power in sports, discussing the application and estimation of mechanical power, the consequences of simplifications, and the terminology. The mechanical power balance consists of five parts, where joint power is equal to the sum of kinetic power, gravitational power, environmental power, and frictional power. Structuring literature based on these power components shows that simplifications in models are done on four levels, single vs multibody models, instantaneous power (IN) versus change in energy (EN), the dimensions of a model (1D, 2D, 3D), and neglecting parts of the mechanical power balance. Quantifying the consequences of simplification of power models has only been done for running, and shows differences ranging from 10% up to 250% compared to joint power models. Furthermore, inconsistency and imprecision were found in the determination of joint power, resulting from inverse dynamics methods, incorporation of translational joint powers, partitioning in negative and positive work, and power flow between segments. Most inconsistency in terminology was found in the definition and application of ‘external’ and ‘internal’ work and power. Sport research would benefit from structuring the research on mechanical power in sports and quantifying the result of simplifications in mechanical power estimations.
Article
We aimed to clarify the mechanical determinants of sprinting performance during acceleration and maximal speed phases of a single sprint, using ground reaction forces (GRFs). While 18 male athletes performed a 60-m sprint, GRF was measured at every step over a 50-m distance from the start. Variables during the entire acceleration phase were approximated with a fourth-order polynomial. Subsequently, accelerations at 55%, 65%, 75%, 85%, and 95% of maximal speed, and running speed during the maximal speed phase were determined as sprinting performance variables. Ground reaction impulses and mean GRFs during the acceleration and maximal speed phases were selected as independent variables. Stepwise multiple regression analysis selected propulsive and braking impulses as contributors to acceleration at 55%-95% (β > 0.724) and 75%-95% (β > 0.176), respectively, of maximal speed. Moreover, mean vertical force was a contributor to maximal running speed (β = 0.481). The current results demonstrate that exerting a large propulsive force during the entire acceleration phase, suppressing braking force when approaching maximal speed, and producing a large vertical force during the maximal speed phase are essential for achieving greater acceleration and maintaining higher maximal speed, respectively.
Article
This study aimed to validate a simple field method for determining force- and power-velocity relationships and mechanical effectiveness of force application during sprint running. The proposed method, based on an inverse dynamic approach applied to the body center of mass, estimates the step-averaged ground reaction forces in runner's sagittal plane of motion during overground sprint acceleration from only anthropometric and spatiotemporal data. Force- and power-velocity relationships, the associated variables, and mechanical effectiveness were determined (a) on nine sprinters using both the proposed method and force plate measurements and (b) on six other sprinters using the proposed method during several consecutive trials to assess the inter-trial reliability. The low bias (<5%) and narrow limits of agreement between both methods for maximal horizontal force (638 ± 84 N), velocity (10.5 ± 0.74 m/s), and power output (1680 ± 280 W); for the slope of the force-velocity relationships; and for the mechanical effectiveness of force application showed high concurrent validity of the proposed method. The low standard errors of measurements between trials (<5%) highlighted the high reliability of the method. These findings support the validity of the proposed simple method, convenient for field use, to determine power, force, velocity properties, and mechanical effectiveness in sprint running. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Article
Fourteen male elite sprinters performed short-distance sprints and jump tests up to 18 days prior to 100-m dash competitions in track & field to determine if these tests are associated with 100-m sprint times. Testing comprised squat jumps (SJ), countermovement jumps (CMJ), horizontal jumps (HJ), maximum mean propulsive power relative to body mass in loaded jump squats (MPPR) and a flying start 50-m sprint. Moderate associations were found between speed tests and competitive 100-m times (r = 0.54, r = 0.61 and r = 0.66 for 10-, 30- and 50-m, respectively, P < 0.05). In addition, the MPPR was very largely correlated with 100-m sprinting performance (r = 0.75, P < 0.01). The correlations of SJ, CMJ and HJ with actual 100-m sprinting times amounted to -0.82, -0.85 and -0.81, respectively. Due to their practicality, safeness and relationship with the actual times obtained by top-level athletes in 100-m dash events, it is highly recommended that SJ, CMJ, and HJ be regularly incorporated into elite sprint testing routines.
Article
The present study aimed to analyse the influence of speed and power abilities in goal situations in professional football. During the second half of the season 2007/08, videos of 360 goals in the first German national league were analysed by visual inspection. For the assisting and the scoring player the situations immediately preceding the goal were evaluated. The observed actions were categorised as: no powerful action, rotation (around the body's centre-line), straight sprint, change-in-direction sprint, jump, or a combination of those categories. Two hundred and ninety-eight (83%) goals were preceded by at least one powerful action of the scoring or the assisting player. Most actions for the scoring player were straight sprints (n = 161, 45% of all analysed goals, P < 0.001) followed by jumps (n = 57, 16%), rotations and change-in-direction sprints (n = 22, 6% each). Most sprints were conducted without an opponent (n = 109, P < 0.001) and without the ball (n = 121, P < 0.001). Similarly, for the assisting player the most frequent action was a straight sprint (n = 137, P < 0.001) followed by rotations (n = 28), jumps (n = 22) and change-in-direction sprints (n = 18). The straight sprints were mostly conducted with the ball (n = 93, P = 0.003). In conclusion, straight sprinting is the most frequent action in goal situations. Power and speed abilities are important within decisive situations in professional football and, thus, should be included in fitness testing and training.
Article
Despite being addressed in a number of previous studies, the controversy regarding the generality vs. specificity of jumping, sprinting, and change-of-direction speed (CODS) abilities still remains unresolved. Here, we tested the hypotheses that jumping, sprinting, and CODS represent separate and specific motor abilities, and that the jumping ability based on concentric and slow stretch-shortening cycle (SSC) is relatively independent of the same ability based on fast SSC. Eighty-seven male college athletes performed 3 concentric/slow SSC and 3 fast SSC jump tests, 4 sprint tests, and 3 CODS tests. The hypotheses were tested by means of the principal component factor analysis (PCA). The applied procedure reduced the greater number of manifest variables to a smaller number of independent latent dimensions or factors and, thereafter, assessed the relationships among them. The PCA revealed a relatively simple and consistent structure consisting of 4 separate factors that explained nearly 80% of variance of the applied tests. The factors appeared to correspond to the sprinting ability, concentric/slow SSC jumping ability, fast SSC jumping ability, and CODS ability. Further analyses revealed that the extracted factors were mainly independent, because they shared only between 6 and 23% of the common variance. These results supported our hypotheses regarding the specificity of jumping, sprinting, and CODS abilities, and specificity of the concentric/slow SSC and fast SSC jumping abilities. Coaches and strength and conditioning professionals should, therefore, use separate performance tests for the assessment of the studied abilities.
Article
Statistical guidelines and expert statements are now available to assist in the analysis and reporting of studies in some biomedical disciplines. We present here a more progressive resource for sample-based studies, meta-analyses, and case studies in sports medicine and exercise science. We offer forthright advice on the following controversial or novel issues: using precision of estimation for inferences about population effects in preference to null-hypothesis testing, which is inadequate for assessing clinical or practical importance; justifying sample size via acceptable precision or confidence for clinical decisions rather than via adequate power for statistical significance; showing SD rather than SEM, to better communicate the magnitude of differences in means and nonuniformity of error; avoiding purely nonparametric analyses, which cannot provide inferences about magnitude and are unnecessary; using regression statistics in validity studies, in preference to the impractical and biased limits of agreement; making greater use of qualitative methods to enrich sample-based quantitative projects; and seeking ethics approval for public access to the depersonalized raw data of a study, to address the need for more scrutiny of research and better meta-analyses. Advice on less contentious issues includes the following: using covariates in linear models to adjust for confounders, to account for individual differences, and to identify potential mechanisms of an effect; using log transformation to deal with nonuniformity of effects and error; identifying and deleting outliers; presenting descriptive, effect, and inferential statistics in appropriate formats; and contending with bias arising from problems with sampling, assignment, blinding, measurement error, and researchers' prejudices. This article should advance the field by stimulating debate, promoting innovative approaches, and serving as a useful checklist for authors, reviewers, and editors.
Article
We interpret the currently available scientific evidence to indicate that strength training should be as specific as possible. The coach or athlete, in designing a strength training programme, should attempt to have the training exercises similate the sport movement as closely as possible, in relation to movement pattern, velocity of movement, muscular contraction type, and contraction force. In the case of sport movements that are performed at high velocity, supplementary training at low velocity may be necessary to induce maximal adaptation within the muscles. Supplementary training with maximal or near maximal eccentric contractions may be beneficial in training for many sports because the large forces generated during this kind of training will stimulate maximal adaptation within the muscles. However, consideration should be given to the greater risk of injury that is associated with eccentric training. Failure to be specific in strength training may result in more than a poor return on the training investment; it may even be counter-productive. For example, the development of increased mass in irrelevant muscle groups may be detrimental in sports which demand a high strength to body mass ratio.
Article
We twice tested the hypothesis that top running speeds are determined by the amount of force applied to the ground rather than how rapidly limbs are repositioned in the air. First, we compared the mechanics of 33 subjects of different sprinting abilities running at their top speeds on a level treadmill. Second, we compared the mechanics of declined (-6 degrees ) and inclined (+9 degrees ) top-speed treadmill running in five subjects. For both tests, we used a treadmill-mounted force plate to measure the time between stance periods of the same foot (swing time, t(sw)) and the force applied to the running surface at top speed. To obtain the force relevant for speed, the force applied normal to the ground was divided by the weight of the body (W(b)) and averaged over the period of foot-ground contact (F(avge)/W(b)). The top speeds of the 33 subjects who completed the level treadmill protocol spanned a 1.8-fold range from 6.2 to 11.1 m/s. Among these subjects, the regression of F(avge)/W(b) on top speed indicated that this force was 1.26 times greater for a runner with a top speed of 11.1 vs. 6.2 m/s. In contrast, the time taken to swing the limb into position for the next step (t(sw)) did not vary (P = 0.18). Declined and inclined top speeds differed by 1.4-fold (9.96+/-0.3 vs. 7.10+/-0.3 m/s, respectively), with the faster declined top speeds being achieved with mass-specific support forces that were 1.3 times greater (2.30+/- 0.06 vs. 1.76+/-0.04 F(avge)/ W(b)) and minimum t(sw) that were similar (+8%). We conclude that human runners reach faster top speeds not by repositioning their limbs more rapidly in the air, but by applying greater support forces to the ground.
Article
The primary aim of this study was to determine reliability and factorial validity of squat (SJ) and countermovement jump (CMJ) tests. The secondary aim was to compare 3 popular methods for the estimation of vertical jumping height. Physical education students (n = 93) performed 7 explosive power tests: 5 different vertical jumps (Sargent jump, Abalakow's jump with arm swing and without arm swing, SJ, and CMJ) and 2 horizontal jumps (standing long jump and standing triple jump). The greatest reliability among all jumping tests (Cronbach's alpha = 0.97 and 0.98) had SJ and CMJ. The reliability alpha coefficients for other jumps were also high and varied between 0.93 and 0.96. Within-subject variation (CV) in jumping tests ranged between 2.4 and 4.6%, the values being lowest in both horizontal jumps and CMJ. Factor analysis resulted in the extraction of only 1 significant principal component, which explained 66.43% of the variance of all 7 jumping tests. Since all jumping tests had high correlation coefficients with the principal component (r = 0.76-0.87), it was interpreted as the explosive power factor. The CMJ test showed the highest relationship with the explosive power factor (r = 0.87), that is, the greatest factorial validity. Other jumping tests had lower but relatively homogeneous correlation with the explosive power factor extracted. Based on the results of this study, it can be concluded that CMJ and SJ, measured by means of contact mat and digital timer, are the most reliable and valid field tests for the estimation of explosive power of the lower limbs in physically active men.
Article
To investigate the relationship between physical fitness and team success in soccer, and to test for differences in physical fitness between different player positions. Participants were 306 male soccer players from 17 teams in the two highest divisions in Iceland. Just before the start of the 1999 soccer season, the following variables were tested: height and weight, body composition, flexibility, leg extension power, jump height, and peak O2 uptake. Injuries and player participation in matches and training were recorded through the 4-month competitive season. Team average physical fitness was compared with team success (final league standing) using a linear regression model. Physical fitness was also compared between players in different playing positions. A significant relationship was found between team average jump height (countermovement jump and standing jump) and team success (P = 0.009 and P = 0.012, respectively). The same trend was also found for leg extension power (P = 0.097), body composition (% body fat, P = 0.07), and the total number of injury days per team (P = 0.09). Goalkeepers demonstrated different fitness characteristics from outfield players. They were taller and heavier, more flexible in hip extension and knee flexion, and had higher leg extension power and a lower peak O2 uptake. However, only minor differences were observed between defenders, midfield players, and attackers. Coaches and medical support teams should pay more attention to jump and power training, as well as preventive measures and adequate rehabilitation of previous injuries to increase team success.
Article
Resisted sprint running is a common training method for improving sprint-specific strength. For maximum specificity of training, the athlete's movement patterns during the training exercise should closely resemble those used when performing the sport. The purpose of this study was to compare the kinematics of sprinting at maximum velocity to the kinematics of sprinting when using three of types of resisted sprint training devices (sled, parachute, and weight belt). Eleven men and 7 women participated in the study. Flying sprints greater than 30 m were recorded by video and digitized with the use of biomechanical analysis software. The test conditions were compared using a 2-way analysis of variance with a post-hoc Tukey test of honestly significant differences. We found that the 3 types of resisted sprint training devices are appropriate devices for training the maximum velocity phase in sprinting. These devices exerted a substantial overload on the athlete, as indicated by reductions in stride length and running velocity, but induced only minor changes in the athlete's running technique. When training with resisted sprint training devices, the coach should use a high resistance so that the athlete experiences a large training stimulus, but not so high that the device induces substantial changes in sprinting technique. We recommend using a video overlay system to visually compare the movement patterns of the athlete in unloaded sprinting to sprinting with the training device. In particular, the coach should look for changes in the athlete's forward lean and changes in the angles of the support leg during the ground contact phase of the stride.
  • I D Pubmed
PubMed ID: 18438225 doi:10.1519/JSC.0b013e31816611ea