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International Journal of Sports Medicine - Ethical Standards in Sport and Exercise Science Research
... Tennis' service action could be divided into three stages: take-off before service, leaving, and landing cushioning, according to the literature (Harriss and Atkinson, 2009). In this study, the kinematics and dynamics of athletes' takeoff and landing cushions were primarily examined. ...
... The biomechanical study of tennis also found that the LLS of athletes have a special impact on the efficiency of foot movement and help athletes achieve higher sports performance (Durand et al., 2010). Appropriate LLS can stimulate the degree of muscle activation to obtain a higher level of GRF and motion impulse through ROM (Harriss and Atkinson, 2009). This experiment discovered that the LLS of level 3 was greater than that of levels 1 and 2. The higher LLS at level 3 was primarily due to a smaller ROM, which LLS could not compensate for in terms of FUS performance. ...
Purpose: The purpose of this study was to examine biomechanical performance of the foot-up serve (FUS) in female tennis players at different skill levels.
Methods: FUS analysis was completed in the biomechanical laboratory by 32 female college tennis players at three different levels. During FUS, 3D-biomechanical data from tennis players’ lower limbs were collected. One-way ANOVA was used to examine differences in kinematic and kinetic data between groups
Results: Range of motion (ROM) of bilateral lower-limb joints revealed significant differences in kinematics performance during both the preparation and landing cushion phases ( p < 0.05). During preparation, Level 3 was significantly longer than Level 2 (P-a = 0.042, P-b = 0.001, and P-c = 0.006). During the flight phase, significant differences between levels 1 and 3 (P-a:0.002) and levels 1 and 2 (P-c:0.000) were discovered (P-a:0.002 and P-c:0.000). There were significant height differences between levels 1 and 2 as well as between levels 1 and 3. (P-a = 0.001, P-c = 0.000). During serve preparation (P-c = 0.001) and landing, GRF’s peak was significantly higher than level 3. (P-c:0.007). Significant differences were found between groups in the LLS preparation stage, with level 3 significantly higher than levels 1 and 2. (P-a = 0.000, P-b = 0.001, and P-c = 0.000); during landing, level 2 LLS was significantly higher than levels 1 and 3. (P-a = 0.000, P-b = 0.000, and P-c = 0.035).
Conclusion: The range of motion of joints and the stiffness of the lower limbs have a significant impact on a tennis player’s FUS performance. A larger of joint mobility and lower-limb stiffness promote better performance during the FUS preparation stage.
... Todos los jugadores poseían un buen estado de salud, acreditado por las pruebas médicas, obligatorias para poder jugar en las competiciones de la Federación Autonómica de fútbol. El estudio se realizó teniendo en cuenta los estándares éticos para la investigación en ciencias del deporte (Harriss & Atkinson, 2009). ...
Resumen. El objetivo de este estudio fue analizar cómo influye en los parámetros técnicos y físicos la forma de reiniciar el juego en diferentes formatos de juegos reducidos en jugadores de fútbol masculino (n=20) de categoría cadete (15.3 ± 0.5 años) pertenecien-tes a la academia de un club profesional de la primera división de fútbol español 2022-2023. Se diseñaron dos juegos reducidos (2x2+2c y 4x4+2c) donde se utilizaba el constreñimiento de reinicio del juego por parte del entrenador y de saque de banda por parte de jugador. Se analizaron las variables físicas externas de distancia total, distancia a diferentes velocidades (7-13 km·h-1 ;13-18 km·h-1 ;18-21 km·h-1 ;21-24 km·h-1), velocidad máxima (<24km·h-1), medias (entre 2 y 3 m. s-2), altas aceleraciones/deceleraciones (> 3 m. s-2) y RPE y, las variables técnicas del pase y el control. Los resultados mostraron diferencias significativas en las variables físicas de baja intensidad y en las acciones técnicas de pase, cuando inicia la acción por el suelo, en el control cuando el balón no va por el suelo y se contacta con otras partes del cuerpo. Estos datos permiten, a través de este constreñimiento, generar una mayor variabilidad técnica a las tareas para que los entrenadores puedan generar escenarios de aprendizaje más próximos al juego. Palabras clave: pedagogía no lineal, entrenamiento, aprendizaje, fútbol, variabilidad. Abstract. The aim of this study was to analyse the influence on technical and physical parameters of the way of restarting the game in different formats of small sided games in male football players (n=20) of cadet category (15.3 ± 0.5 years) belonging to the academy of a professional club of the first division of Spanish football 2022-2023. Two small sided games (2x2+2c and 4x4+2c) were designed using the coach's restart constraint and the player's throw-in constraint. The external physical variables of total distance, distance at different speeds (7-13 km-h-1;13-18 km-h-1;18-21 km-h-1;21-24 km-h-1), maximum speed (<24km-h-1), average (between 2 and 3 m. s-2), high accelerations/decelerations (> 3 m. s-2) and RPE and, the technical variables of passing and control were analysed. The results showed significant differences in the low intensity physical variables and in the technical actions of passing, when initiating the action on the ground, in control when the ball does not go on the ground and contact is made with other parts of the body. These data allow, through this constraint, to generate a greater technical variability to the tasks so that coaches can generate learning scenarios closer to the game. Introducción En los últimos años ha surgido la necesidad de adoptar una visión diferente sobre el aprendizaje de la técnica en los deportes colectivos, donde tradicionalmente se enten-día que el aprendizaje de la ejecución técnica tenía que ser un paso previo al desarrollo de los aspectos decisionales (Mitchell et al., 2006) y en donde existe un modelo ideal de resolución o de ejecución técnica sin tener en cuenta la información del entorno (Headrick et al., 2015). Para dar respuestas pragmáticas, a través del entrenamiento, han surgido propuestas en diferentes deportes a través de en-foques como el Constraints-Led Approach (Davids et al.,2008) o la pedagogía no lineal (Correia et al., 2018), que tal como indican Clark et al. (2018) pueden lograr mejores resultados en el aprendizaje que los enfoques cognitivos y conductistas. Una de las finalidades de estos tipos de enfoques es la manipulación de los constreñimien-tos de la tarea, los cuales promueven adaptaciones del comportamiento del jugador (Lacasa-Claver et al., 2021). En este sentido el proceso de aprendizaje es un proceso dinámico y de auto-organización, donde el reto está en desafiar a quien aprende a través de la exploración de patrones en entornos no-lineales (Chow et al., 2015). En esta línea, son varias las investigaciones que se han desarro-llado en diferentes modalidades deportivas, tanto indivi-duales (Lacasa-Claver et al.
... The study received approval from the scientific commission and was conducted in accordance with recognised ethical standards. 11 Each team provided written informed consent, while assent was obtained from individual athletes. Participants were also informed that participation was entirely voluntary and that they could withdraw at any time. ...
Objective: Evaluate the anthropometric characteristics of male rink hockey goalkeepers, and to compare the variation according to their competitive level (international vs. non-international). Methods: Body mass, stature, sitting height, arm span, waist and hip circumferences and four skinfold measurements (triceps, medial calf, subscapular and supraspinale) of international (n = 12) and non-international (n = 23) goalkeepers were taken. Body mass index (BMI, weight/height2), the sum of four skinfolds, the sitting height/stature ratio, waist/hip ratio and the relative arm span were also calculated. Results: International rink hockey goalkeepers have lower values of subcutaneous adiposity for the sum of the four skinfolds (P = 0.042; d = 0.76) particularly in the triceps (P = 0.016; d = 0.87) and are taller than non-international goalkeepers (+3.8 cm [2.2%]; 180.5 ± 7.0 vs. 176.6 ± 4.8 cm; t = 1.920; P = 0.064; d = 0.65). Conclusion: The findings could indicate that stature and body fat may have important implications for scouts regarding the selection process and coaches that work with players on developing performance. Future research should investigate the extent to which different anthropometric measures influence performance in rink hockey goalkeepers.
... The concentration measures of plasma creatinine, supplements at the time of this study (or prior to), nor did they report any injuries or medical problems that would affect the study results or their ability to train. Ethical approval was obtained from the Institute of Sport -National Research Institute, Poland, with full adherence to ethical standards in sport and exercise research [13]. For example, each athlete received a full briefing on the study aims, experimental procedures, and potential benefits, before providing written and verbal informed consent. ...
Boxing is a combat sport linked to muscle damage (e.g., soreness, rising creatine kinase [CK]) and energetic biomarkers (e.g., urea, glucose). These factors have not, however, been examined dynamically in terms of day-to-day, lagged and reciprocal effects during normal training. This study investigated the dynamic interplay between muscle damage and energetics in male boxers during a short training block. Thirteen amateur boxers were monitored over 16 consecutive days during early-season training. The participants were assessed each morning for plasma CK, urea, glucose, and creatinine (days 1 and 16 only) concentrations, before self-reporting muscle soreness (1–10 scale). Within-person contemporaneous (lag-0) and temporal (lag-1) networks were estimated using multilevel vector autoregression. Muscle soreness, CK, urea, and glucose presented different trajectories with training, but with some heterogeneity reflecting within-person variances (47% to 78%). The contemporaneous network yielded a significant positive edge (or correlation) between CK and soreness (r = 0.44), along with negative CK-glucose and glucose-urea edges. More significant edges emerged in the temporal network, with soreness linked to CK (r = 0.19), glucose (r = -0.28) and urea (r = 0.22), whilst the CK-glucose edge sign switched. In summary, daily fluctuations in muscle damage and energetic activity, which presented in a normal physiological range, were highly variable among boxers during early-season training. Within-person networks indicated some interrelatedness between CK, soreness, urea, and glucose, although the nature and presence of these relationships were contingent on temporal ordering. These inconsistences reflect the pleiotropy of energetic biomarkers in training and recovery.
... The participants agreed to have their data used for scientific purposes and a future publication and signed an informed consent form. Measurements were carried out in accordance with the ethical standards of the Declaration of Helsinki, the ethical standards in sport and exercise science research (Harriss & Atkinson, 2015). ...
This study aimed to compare the effect of a morning physical intervention on the body composition of young women (n = 8, mean age ± SD = 23.1 ± 1.0 years, mean height ± SD = 168.9 ± 5.8 cm, mean weight ± SD = 66.2 ± 6.8 kg) of the morning chronotype (M-types) vs. young women (n = 25, mean age ± SD = 21.4 ± 1.5 years, mean height ± SD = 167.1 ± 5.4 cm, mean weight ± SD = 65.6 ± 7.8 kg) of the neither chronotypes (N-types). We used bioimpedance analysis to detect changes in the following indicators: weight, body mass index, fat mass (FM%), fat free mass (FFM), muscle mass (MM), total body water (TBW), extracellular and total body water ratio (ECW/TBW), extracellular and body cell mass ratio (ECM/BCM), and phase angle (PA). Intervention effects in groups were compared and evaluated by Cohen’s d within the statistical procedure of paired samples t-test, which did not show any significant differences in all indicators, except PA, between the pre-test and post-test (p>0.05). Statistical improvement was denoted and examined in the PA of the N-types. The most significant difference was found in the ECM/BCM indicator, which was stimulated more effectively in M-types after the morning intervention compared with the N-types. M-type participants improved in ECM/BCM (d = 0.62) and PA (d = 0.70) with a medium effect, but scored worse in FM% (d = 0.47) with a small effect, FFM (d = .43), MM (d = 0.42), and TBW (d = 0.40), whereas no effect was found in ECW/TBW (d = 0.15). N-type participants improved in PA (d = .60) with a medium effect, FFM (d = 0.29), MM (d = 0.28), and ECW/TBW (d = 0.28) with a small effect; no effect was observed in ECM/BCM (d = 0.01), FM% (d = 0.03), and TBW (d = 0.04). The results showed that the ECM/BCM and PA parameters were more sensitive than the other parameters. Our findings indicate the importance of further exploration and examination of the problem of time effect examination on particular chronotypes.
... The research was conducted in accordance with the ethical standards of sports science (Harris and Atkinson, 2009). Ethical committee approval was not required to, as only publicly available data was used. ...
Comparing the scores of performances and chronological age in participants of Rhythmic Gymnastics Continental Championships in one Olympic cycle (2017-2020) has the potential to indicate the global differences in the development of this sport. The aim of the study was to, 1) identify the events characterized by the highest/lowest gymnasts’ achievements based on judges scores, and determine the differences in total scores, difficulty and execution of all-around, hoop, ball, clubs and ribbon in qualification competition, and finals, across Continental Championships (CC), and 2) compare the chronological age of CC participants. The material was obtained from the official RG Results Books and official documents of five Continental Championships. The total sample included individual rhythmic gymnasts (n=116) that participated in all-around and finals of: 15th African Championships (ACh), Sharm El Sheikh, EGY, (n=15); Oceania RG CC (OCh), Carrara, QLD, AUS, (n=17); 12th Senior Rhythmic Gymnastics Asian Championships (AsCh), Tashkent, UZB, (n=11); 37th European Championships in Rhythmic Gymnastics (ECh), Varna, BUL, (n=52); Rhythmic Gymnastics Senior Pan American Championships (PACh), Rio de Janeiro, BRA, (n=21). For each final (hoop, ball, clubs, ribbon), the eight qualified gymnasts’ scores were compared except for OCh where only six gymnasts for each apparatus qualified. The gymnasts’ chronological age was also calculated. The Kruskal-Wallis test and a post-hoc Bonferroni test at the 95% confidence level were used. The comparative analysis determined the events that were characterized by the highest or lowest judges’ scores and showed significant differences in total, difficulty, and execution scores for hoop, ball, clubs, and ribbon between all-around qualification competitors (p<0.001), and between apparatuses finalists (p<0.001) across CC participants. The chronological age significantly differentiated participants in all-around competition (H=12.6, p<0.01, η2=0.078) showing gradation from the youngest to the oldest: ACh<OCh<ECh<AsCh<PACh. Moreover, the ball and ribbon ECh finalists were significantly older from those of OCh and ACh finalists (p<0.001). The results of the present study may be used in future analysis of scores and chronological age of rhythmic gymnasts representing particular CC to monitor the trend between front rank events’ competitors and those with lower achievements. This can be informative for gymnastics federations and state institutions that are able to organizationally and systemically support the sport development.
... and by the local Research Ethics Committee (number: 3,705.954). It is important to cite that the study was performed both in accordance with the Ethical Standards presented in 2016 by Harris and Atkinson (Harriss and Atkinson, 2009) and in accordance with the Declaration of Helsinki (World Medical Association Inc, 2009). ...
... and by the local Research Ethics Committee (number: 3,705.954). It is important to cite that the study was performed both in accordance with the Ethical Standards presented in 2016 by Harris and Atkinson (Harriss and Atkinson, 2009) and in accordance with the Declaration of Helsinki (World Medical Association Inc, 2009). ...
Purpose
To investigate the effects of triathlon racing under extreme conditions on metabolic and immune/inflammatory responses.
Methods
Thirteen amateur athletes participated in an extreme triathlon competition (swim – 3.8 km; cycling – 180 km; running – 4 2 km; with a 3,700 m accumulated altitude). Blood samples were collected on three different occasions: pre-competition (baseline), immediately post-competition (IM), and 12 h post-competition (12 h) to evaluate glycemic and lipid profiles, leukocytes count, and cytokines levels in plasma and in whole-blood cell culture supernatant stimulated or not with LPS.
Results
Decreased glucose and triglycerides levels, increased LDL, and a significant leukocytosis were observed at IM and 12 h compared to baseline. In addition, higher serum levels of IL-6, IL-8, and IL-10 were found at IM than in baseline and post-12 h. Whereas increased IL-12p40 levels were observed for 12 h compared to baseline. At baseline, in LPS-stimulated cell culture, IL-6, IL-8, and IL-12p70 were higher, while IL-12p40 levels were lower than non-stimulated cell culture. At IM, IL-12p40 levels were unchanged, while higher levels of other cytokines were found in LPS-stimulated cell culture compared to non-stimulated cell culture. The 12 h results showed higher levels of IL-6, IL-8, and IL-10 in LPS-stimulated cell culture than in non-stimulated cell culture. Additionally, a significant negative correlation between circulating glucose levels and IL-6 was found.
Conclusion
The triathlon competition's performance under extreme conditions has remarkable impacts on the lipid profile and systemic immune/inflammatory responses. For the first time, significant alterations in the cytokine responses of whole blood cell culture to LPS-stimulation in baseline, IM, and 12h were demonstrated.
... However, 2313 figure skaters from 59 countries (males = 1059, females = 1254) were included in the present study due to the lack of data for the others. Design and procedures -The procedures performed in the present study are in accordance with the ethical standards of the revised ethical Declaration of Helsinki (Harriss & Atkinson, 2009;World Medical Association, 2013). Following the institutional ethical approval from XXX University (information temporarily suppressed to guarantee authors' anonymity), all the information about athletes (i.e. ...
Relative age effect is a worldwide phenomenon referring to the subtle age-related (dis)advantages of athletes in the same age category, particularly in soccer and ice-hockey. Although well-established knowledge has been achieved to a certain extent, a need for further research is still valid considering different demands of each sport and possible differences in the course of time. The purpose of this study was to investigate the participation trends among elite figure skaters in the world regarding relative age effect, and to determine whether a decade has made a difference. The study sample was composed of 2313 figure skaters competing between 2009-10 and 2018-19 seasons. They were categorized into four quartiles according to their birth months. Total and season by season analyses were conducted to project any possible seasonal effect over a decade. Chi-square (χ²) goodness-of-fit tests were used to determine asymmetries in distributions, and odds ratios (OR) and 95% confidence intervals were used to compare quartiles with each other. Effect sizes were calculated using Cramer’s V (V). The results differed for disciplines and genders. Relatively older male skaters in pairs discipline were significantly overrepresented (χ² = 8.528, p = 0.036, V = 0.11) and a trend favoring relatively younger skaters was determined in men’s singles discipline through the last three seasons. Season-based analyses revealed no relative age effect except for the last three seasons. In conclusion, disciplines of figure skating seem to have complex and different demands regarding relative age effect, and time seems to become a determinant for further studies.
... Overall, 100 game records for the 22 players were included in the final analyses. The study was in accordance to the Declaration of Helsinki (Harriss & Atkinson, 2014) and approved by the Institutional Review Board of the Polytechnic University of Madrid, Spain. ...
The main aim of this study was identifying the internal demands during competition including the impact of analysis method (i.e., average vs. peak demands). A secondary aim was to analyze the effects of playing time on the internal demands (average and peak). Methods: Twenty-two professional basketball players were monitored during 11 games. The following internal workload variables were recorded as averages (i.e., value per minute considering the entire game) and peak values (i.e., greatest 1-minute window): 1) average Heart Rate (HR), peak HR, average Respiration Rate (RR), peak RR, average Ventilation (VE), peak VE, average VO2 and peak VO2. Results: Signifcantly higher peak values (very large effect size) for all internal variables were evident when compared to their average demand. Concerning playing time comparison, signifcantly greater average
values were reached for large playing time group (24.54 ± 3.23 min) for all variables
compared to small playing time group (14.13 ± 3.78 min). However, non-signifcant differences were apparent between large playing time and small playing time group at their internal PD. Conclusions: Understanding internal load demands using averages values drastically underestimates the internal peak values of games. Thus, 14 minutes of total playing time (1.5 quarters; ~37% of a game) is enough to expose to the players to internal peak demands.
... Overall, a total of n = 270 quarters (Q1 n = 70, Q2 n = 69, Q3 n = 69 and Q4 n = 62) played by the 13 players were included in analyses. The study was in accordance to the Declaration of Helsinki (Harriss and Atkinson 2014) and approved by the Institutional Review Board of the Polytechnic University of Madrid, Spain. ...
The purpose of this study was to compare external peak demands (PDs) across quarters(Q) in basketball. Thirteen elite, junior, male basketball players were monitored using electronic performance tracking systems. There were studied intervals for different time windows to determine the external PD for distance (m); player load; distance covered in four different zones; accelerations; and decelerations. A mixed linear model was run to identify differences among quarters, and the auto-correlation function was carried out to determine fluctuations across the whole game. The results showed significant differences between Q1 vs. Q2 for distance, player load, and standing–walking distance; between Q1 vs. Q3 for distance, player load, and HSR; between Q1 vs. Q4 for distance, player load,standing–walking, and HSR; and between Q3 vs. Q4 for distance and player load. These findings suggest that external PD for running-based demands (distance, player load, and high-speed running) decrease across basketball games with the most notable declines occurring between the first and fourth quarters. Nevertheless, it is important to note that non-significant differences were found between quarters for several external PD variables (jogging, running, acceleration, and deceleration) across different time windows. Findings from the present study reinforce the importance of considering specific PD variables for different functions due to the specific insight each provides.
... In part I, we tried to quantify the influence of the body mass and here we study the effect of the age onto the final time tfas the crucial result. The authors conducted their research ethically, according to international standards and as required by the journal as described in Harriss & Atkinson (2009). ...
The career of a sprinter is analyzed with U. Bolt achievements as an example. The effects of the increase of body mass and ageing are discussed within the framework of the polynomial models for the velocity, muscular isometric force and age. The analysis presented demonstrates the influence of the BM factor in analyzed racing. The nonlinear increase of the BM for 9 kg in the period 2009 - 2017 in was one of the reasons of Bolt’s unsuccessful attempt to repeat or confirm the time 9.58 s. Another limiting factor was the fact that due to the age, Bolt was not able to increase isometric muscular force which, after the year of maximal efficiency (2009) decreased.
... El diseño del presente estudio se apega los principios éticos que protegen a los sujetos que participen en estudios científicos, fundamentados por la declaración de Helsinki y la Asociación Médica Mundial. Considerando el respeto por la integridad del individuo y esclareciendo todos los riesgos posibles en su desarrollo, este estudio se apegó a los estándares éticos internacionales en ciencias del ejercicio y deporte (18). El presente trabajo cuenta con aprobación del comité de ética de la Universidad Metropolitana de Barranquilla. ...
Objetivo: el objetivo del estudio fue identificar la relación entre los resultados de las pruebas saltabilidad horizontal y vertical con la incidencia las lesiones musculoesqueléticas de miembros inferiores en futbolistas de un club de la liga profesional colombiana. Materiales y métodos: se realizó un estudio analítico, exploratorio, en 30 futbolistas de la nómina profesional del Club Deportivo Atlético Junior F.C. Al inicio de la temporada se evaluaron las características antropométricas, así mismo como la saltabilidad y asimetrías funcionales de las extremidades inferiores a través de pruebas de saltos verticales (CMJ y CMJs) y horizontales (3-Hop Test). El análisis consistió en la comparación los registros de las variables estudiadas entre los futbolistas con (lesionados n=11) y sin lesión (no lesionados n=19) en el transcurso del primer semestre de la temporada 2019. Resultados: en los hallazgos no se encontraron diferencias estadísticas entre los grupos en las características biológicas, antropométricas y de composición corporal (p>0,05). Derivado de los hallazgos en la saltabilidad vertical, no se observaron diferencias significativas en las asimetrías funcionales entre grupos (p>0,05), sin embargo, si se encontraron diferencias en las pruebas de saltabilidad horizontal entre lesionados y no lesionados (p<0,01). Conclusión: de este estudio podemos concluir que, en comparación a los futbolistas profesionales sin lesiones, se encontraron significativamente mayores asimetrías funcionales detectadas a través de la prueba de saltabilidad horizontal en los deportistas con lesión.
... In part I, we tried to quantify the influence of the body mass and here we study the effect of the age onto the final time tfas the crucial result. The authors conducted their research ethically, according to international standards and as required by the journal as described in Harriss & Atkinson (2009). ...
JANJIC, N.; KAPOR, D.; DODER, D.; RASOVIC, P. & RADISIC, L. How does the increase of body mass and ageing affect sprinter's results in a 100m run. Int. J. Morphol., 39(6):1543-1546, 2021. SUMMARY: The career of a sprinter is analyzed with U. Bolt achievements as an example. The effects of the increase of body mass and ageing are discussed within the framework of the polynomial models for the velocity, muscular isometric force and age. The analysis presented demonstrates the influence of the BM factor in analyzed racing. The nonlinear increase of the BM for 9 kg in the period 2009-2017 in was one of the reasons of Bolt's unsuccessful attempt to repeat or confirm the time 9.58 s. Another limiting factor was the fact that due to the age, Bolt was not able to increase isometric muscular force which, after the year of maximal efficiency (2009) decreased.
... and by the National Research Ethics Committee (number CAEE:218170619.3.0 000.5505). This study agreed with the Ethical Standards of Exercise Practice (42), and all experiments were performed following the Declaration of Helsinki (43). Clinical data and physical examinations were also collected at the Discipline of Geriatrics and Gerontology from the Federal University of São Paulo (UNIFESP). ...
Oxidative stress is an important factor in the formation of atherosclerotic plaques. High-density lipoprotein (HDL) harbors paraoxonase-1 (PON-1) and glutathione peroxidase (GPx), key enzymes in the protection against the harmful effects of oxidative stress. Although exercise training can increase both HDL-c content and its antioxidant action, and glutamine (Gln) intake also promotes GPx-based defenses, the association between exercise training and Gln in the regulation of PON-1 activity was not explored. Therefore, the objective of this study was to investigate the effects of Gln supplementation on the redox balance and on the total HDL antioxidant capacity by evaluation of the activity of PON-1 and GPx enzymes in physically exercised elderly individuals compared to non-exercised ones.
Methods
Fifty-one practitioners of a combined exercise training program (CET, age: 71.9 ± 5.7 years) and 32 non-practitioners (NP, age: 73 ± 6.3 years) participated in the study. CET and NP groups were separated into 2 subgroups according to the supplementation: Gln, 0.3 g/kg/day + 10 g maltodextrin (CET-Gln, n = 26; and NP-Gln, n = 16) or placebo, 10 g maltodextrin (CET-PL, n = 25; and NP-PL, n = 16). Blood samples were drawn at baseline and after 30 days after commencement of the supplementation for biochemical and enzyme activity analyses.
Results
Increased HDL-c, total peroxidase (PRx), and GPx activities were found in both CET-Gln and NP-Gln after the supplementation period, compared to baseline, in opposition to CET-PL and NP-PL groups. PON-1 activity increased only in CET-Gln. In both CET-Gln and NP-Gln groups, there was a reduction of the total peroxides/PRx, iron/PRx, and total peroxides/GPX ratios after supplementation. In CET-Gln, thiobarbituric acid-reactive substances (TBARS)/PRx and TBARS/GPx ratios were also lower after supplementation. CET-Gln and CET-PL subgroups had lower glycemia than NP-Gln and NP-PL, either at baseline or after the supplementation periods. The other parameters were unchanged after supplementation [total cholesterol, LDL-c, triglycerides, non-HDL cholesterol, total peroxides, TBARS, iron serum, Trolox-equivalent antioxidant capacity (TEAC), and uric acid].
Conclusions
Gln supplementation can increase glutathione peroxidase activity regardless the individuals were physically active or sedentary, but the PON-1 activity only increased in physically active individuals. These results show the potential of Gln supplementation in the maintenance of the vascular redox balance, with potential implications for atherogenesis protection.
... La présente étude a été conduite en respectant les standards éthiques (Harriss & Atkinson, 2009) et a été approuvée par le comité éthique de l'Université Paris-Est. Les participants ont fourni leur consentement éclairé. ...
The aim of this study is to test the Regulatory Focus Theory to predict emotional intensities after competition. A sample of gymnasts (n = 273 ; 239 women) competing at different levels was randomly confronted with two precompetitive contexts. The first one induced prevention-focused strategy (Closses) whereas the second one induced promotion-focused strategy (Cgain). Then, from each context, competition results were proposed (Succes vs Failure). After lecture of each context, participants completed the regulatory focus strategies scale, and after the presentation of results, they completed the emotional frequency questionnaire. According to hypotheses, mixed ANOVAs with repeated mesures revealed that (a) cheerfulness was significantly greater in Cgain than Closses, and conversely, (b) agitation was greater in Closses than Cgain. In a particularly interesting way, the study revealed results opposed to the hypotheses, dejection being significantly greater in Closses than Cgain, suggesting a specificity of sport competition context on emotion.
... Based on Regulatory Fit Theory (Higgins, 2000(Higgins, , 2005, we hypothesized that when the regulatory strategy (Prevention vs. Promotion) fitted with the reward structure (Gains vs. Losses), ensuring a regulatory fit situation, performance would be better than in a mismatch situation. The current research was conducted in accordance with the Helsinki declaration and ethical standards (Harris & Atkinson, 2009). It was approved by the ethics committee of Paris-Est University. ...
The purposes of this research were: 1) in a preliminary study, to identify regulatory strategies used by players and coaches according to situation reward structure (Gains vs. Losses); and 2) in the main study, to analyse the effect of the interaction between situation reward structure (Gains vs. Losses) and regulatory strategy (Prevention vs. Promotion) on team performance (scoring a goal) in real-world settings. In the preliminary study, 25 adult male handball players and 19 coaches playing and coaching at national level in the French championships completed a version of the Regulatory Focus Strategies Scales after reading four handball game scenarios (two gain-oriented and two loss-avoidance oriented). Two-way ANOVA with repeated measures revealed that when the reward structure was gain-oriented, participants had higher scores in promotion regulatory strategy than in prevention regulatory strategy, and conversely. For the main study, a sample of 199 game phases was selected from 84 games played in the Lidl Star League (2017-2018 season). Mixed method analysis revealed a significant team regulatory fit effect, that is an interaction effect between reward structure and regulatory focus strategy on team performance. When there was a fit, both in loss-avoidance oriented and gain-oriented reward structure, performance was higher (OR = 1.64 and OR = 0.86, respectively) than when there was a mismatch (OR = 0.59 and OR = 0.27). These results confirm the applicability of the Regulatory Fit Theory in a real-world setting with professional players, and extend grounded social cognition research regulatory fit literature to team level.
... The Institutional Review Board approved the study. This study has been performed in accordance with the ethical standards 13 . ...
Objeto: El objeto de este estudio es evaluar si la práctica del surf de nieve está asociada con un patrón diferente de lesiones, en comparación con la práctica del esquí alpino. Métodos: Fueron analizadas todas las fichas de asistencia médica de los accidentados atendidos en el Centro Médico de la estación de esquí de Masella, durante cinco temporadas (2003-2008). Los grupos de surf de nieve y esquí alpino se compararon utilizando la prueba de chi-cuadrado o el test de Fischer para las variables categóricas y la prueba de t de Student o la prueba de Mann-Whitney para variables continuas. El análisis de varianza (ANOVA) se utilizó para la comparación de más de dos grupos. Cuando las variables no cumplían los supuestos de normalidad, se aplicó la prueba de Kruskal-Wallis se aplicó. La significación estadística se fijó en P <0,05. Resultados: Durante este período, fueron atendidas 9.147 vícti-mas (6.101 fueron esquiadores y 2.789 eran practicantes de surf de nieve). En comparación con los practicantes de esquí alpino, entre los accidentados durante la práctica de surf de nieve se observó que había un mayor número de principiantes (49,5 vs 41,5%), el uso del casco protector era menor (37,8% vs 44,9%), tenían menos heridas incisas y contusas (5,8 % vs 8,5%), menos lesiones de las extremidades inferiores (21,2% vs 47,4%), menos lesiones del dedo pulgar (3,2% vs 7,8%), y menos esguinces de rodilla (2,8% vs 14,7%). Por otra parte, presentaban un mayor porcentaje de fracturas óseas (18,6% vs 6,7%), de lesiones de extremidades superiores (57% vs 29,2%), de lesiones de muñeca en general (16,8% vs 2,5%), de fracturas distales de radio (12,3% vs 1,6%) , de luxaciones de hombro (2,9% vs 1,6%), de fracturas de clavícula (2,4% vs 1,4%), y de lesiones del tronco (2,8% vs 2%). Todas estas comparaciones fueron estadísticamente significativas (P <0,05). Conclusión: Los resultados de este trabajo demuestran que el surf de nieve tiene un patrón de lesiones distinto del que se observa en la práctica del esquí alpino, el conocimiento de las cuales puede influir en la prevención de accidentes de surf de nieve. Las estrategias propuestas para reducir las lesiones consisten en una revisión de la metodologia de aprendizaje y entrenamiento, el uso rutinario del casco y la evaluación de los protectores de espalda para adaptarlos a los deportes de nieve. Palabras clave: (MeSH terms): Lesiones de esquí. Deportes de nieve. Heridas y lesiones. Purpose: The purpose of this study was to assess whether the practice of snowboarding is associated with a different pattern of injuries as compared with alpine skiing. Methods: All consecutive patients with snow sports injuries attended at the Medical Center of Masella ski resort, during five ski seasons (2003-2008) were analyzed. A comparison was made of the groups of alpine skiers and snowboarders, using the chi-square (2) test or the Fisher's exact test for categorical variables, and the Student's t test or the Mann-Whitney U test for continuous variables. The analysis of variance (ANOVA) was used for the comparison of more than two groups. When variables did not fulfill assumptions of normality, the Kruskal-Wallis test was applied. Statistical significance was set at P < 0.05. Results: During this period, a total of 9,147 accident victims were attended (6,101 were alpine skiers and 2,789 were snowboarders). When injured snowboarders were compared with injured alpine skiers, it was noted that the percentage of beginners was larger (49.5% vs 41. 5%) and snowboarders were less likely to use helmet (37.8% vs 44.9%), to have lacerations (5.8% vs 8.5%), to have lower extremity injuries (21.2% vs 47.4%), to have thumb lesions (3.2% vs 7.8%), and to have knee sprains (2.8% vs 14.7%). In addition snowboarding was associated with higher percentages of bone fractures (18.6% vs 6.7%), upper extremity injuries (57% vs 29.2 %), wrist injuries in general (16.8% vs 2.5%), distal radius fractures (12.3% vs 1.6%), shoulder dislocations (2.9% vs 1.6%), clavicle fractures (2.4% vs 1.4%), and trunk injuries (2.8% vs 2%). All these comparisons were statistically significant (P < 0.05). Conclusion: This study show that snowboarding has a different pattern of injuries seen in alpine skiing, the knowledge of which could influence snowboarder accident prevention. Strategies for prevention consist of training courses, the routine use of helmets, and the evaluation of back protectors in order to adapt to snow sports.
... The study was carried out in accordance with the ethical standards of Sports Sciences [35]. The protocol was approved by the Universidade da Coruña's Teaching and Research Ethics Committee, in the framework of implementing a wider proposal within the Euro-American Physical Activity, Education and Health Network. ...
The imbalances between the actual physical activity (PA) of adolescents and the subjective perception both they and their parents have in this regard can play an important role in perpetuating inactive lifestyles. The aim of this study is to analyse these discrepancies by considering gender as a conditioning factor. The participants in the study were 1697 adolescents, 1244 mothers and 1052 fathers in the educational communities of 26 secondary schools located in urban environments of the Autonomous Community of Galicia (Spain). With regard to actual physical activity, a high prevalence of sedentarism (82.1%) was revealed, this being even more acute in girls (87.8%). However, the perceived levels of activity differed significantly from the actual ones with a clear general overestimation both by the adolescents and their parents. When further exploring the data, gender influences were also detected both in adolescent and parental perceptions, since the high rates of overestimation in sedentary individuals were lower in girls and, on the contrary, the low rates of underestimation in active individuals were higher in girls. Moreover, although the level of agreement between actual and perceived physical activity was low overall, with Cohen’s kappa values ranging from 0.006 to 0.047, the lowest values were observed in the case of girls. In conclusion, both the adolescents and their parents were incapable of correctly assessing the actual physical activity of the former, so it seems that the general population lacks knowledge about the amount of physical activity that adolescents need to do to achieve a healthy lifestyle. Consequently, it would be advisable to implement health education campaigns and awareness-raising interventions directed to young people as well as to their parents and, in doing so, gender must be considered by establishing distinct program designs in terms of this variable.
... The study met the ethical standards used in sport and exercise science, disclosing only publicly available data (Harris & Atkinson, 2009). ...
Trends and developments in rhythmic gymnastics concern all the fundamental and detailed aspects that strategically participate in shaping a new dimension of this sport for the next Olympic cycle. The FIG Code of Points, a document that directs the activity in rhythmic gymnastics at world level, has undergone significant changes from one Olympic cycle to another. A constant priority of the specialised international body is to establish a unitary and objective line in the training of gymnasts. The changes of content in the Code of Points, in terms of specific requirements, reflect the progress made regarding the technical, artistic and execution-related aspects. Therefore, a critical analysis is regularly needed to see the impact of regulations on the competitive performance at the end of each Olympic cycle. Competition analysis provides highly valuable data on qualitative and quantitative gains, value distribution, social impact and the higher level reached at a given time in relation to the ideal model established by the FIG Code of Points. This study aims to identify whether the regulations provided by the FIG Code of Points for the last 6 Olympic cycles have produced changes in addressing group compositions under the artistic aspect. The research was conducted on the first 8 teams in the rankings of the World Championships for the group event during the last 6 Olympic cycles. Through documentation and video recordings, we have identified the vectors that can influence the mechanisms involved in creating group compositions.
... Los participantes, al igual que sus padres o responsables de su cuidado, fueron informados de manera verbal y escrita sobre los objetivos del estudio, los beneficios y posibles riesgos de su participación, así como del procedimiento relacionado con la recolección de datos; de esta forma, se realizo la respectiva firma del consentimiento informado. Este estudio fue elaborado siguiendo las normas científicas, técnicas y administrativas para la investigación de la República de Colombia planteadas en la Resolución No. 8430 de 1993(Ministerio de Salud, 1993, así como las recomendaciones éticas para la investigación científica en el deporte y el ejercicio físico (Harriss & Atkinson, 2015) y los principios éticos para la investigación en seres humanos de la Declaración de Helsinki (WMA, 2017). ...
El objetivo de la presente investigación fue estudiar los efectos de la Potenciación Post-Activación (PPA) en la aceleración de los atletas velocistas colombianos, de tal forma que se propongan diferentes métodos de entrenamiento, con el propósito de mejorar el rendimiento de los deportistas. Participaron nueve atletas velocistas de la Selección Colombia Juvenil de Atletismo (4 hombres: Edad 16,9±.3 años; peso corporal 63,0±6,6 kg; talla 171,5±6,6 cm; y, 5 mujeres: edad: 17,1±.4 años; peso corporal 63,0±6,7 kg; talla 174,2±8,5 cm). Se aplicó el Protocolo de Bosco (Abalakov, Drop Jump y Multisaltos en 15 s) con el fin de determinar el estímulo potenciador y la prueba de 30 m con salida detenida pre y post estímulo potenciador. Para evaluar el efecto del estímulo potenciador en los resultados del test de Abalakov y la prueba de aceleración en 30 m, se realizó la prueba de t Student para muestras relacionadas, con una significación de p<.05. La normalidad en el comportamiento de las variables se comprobó a través del resultado obtenido por la prueba de Shapiro Wilk, aplicado a muestras menores de 30 individuos. Todos los atletas evidenciaron una mejora luego de aplicarse el estímulo potenciador, tanto en el test de Abalakov como en la prueba de aceleración en 30 m; presentando diferencia significativa en las medias de los resultados de los velocistas en el test de Abalakov (p=.000) y la prueba de aceleración de 30 m (p=.002) antes y después de un estímulo potenciador.
... Our primary goal was to collect sufficient amount of data for an analysis to determine the basic echocardiographic parameters that measure the effect of physical activity on the heart as we described earlier (13). This study meets the ethical standards of the IJPM (14). ...
Background
Global physical inactivity pandemic is responsible for more than 5 million deaths annually through its effects on non-communicable diseases. This requires urgent intervention.
Objective
To investigate associations of physical activity with cardiovascular fitness in a cross-sectional retrospective observational study. Data were collected for 21 years from 2530 healthy volunteers and athletes representing the entire spectrum of physical activity from the totally inactive sedentary persons to the highly trained national athletes.
Methods
Simple echocardiographic parameters of cardiovascular fitness were analyzed. Cardiac fitness was characterized by reduced resting heart rate, increased relative left ventricular muscular mass, improved left ventricular diastolic function and peak exercise oxygen consumption.
Results
We found that even moderate exercise is associated with improved cardiac fitness. The largest improvement of fitness was observed between the inactive and the least active group, whereas fitness decreased in the highly trained national athletes enduring up to 20 training hours per week.
Conclusions
Our finding that moderate exercise is associated with positive changes in sedentary persons makes sense only in the light of evolution. Human endurance running performance capabilities that emerged ~2 million years ago are evolutionary coded and seems to be awakened even by moderate exercise. This finding would help physicians to encourage patients for doable and sustainable behavioral change who are currently inactive and find physical exercise intimidating. (Word count: 218)
Abbreviations
CV (cardiovascular)
CVD (cardiovascular disease)
CVH (cardiovascular health)
HD (heart disease)
BSA (body surface area)
LV (left ventricular)
RHR (Resting Heart Rate)
Key Points
This cross-sectional retrospective observational echocardiographic study of 2530 healthy volunteers and athletes representing the entire spectrum of physical activity from the totally inactive sedentary persons to the highly trained national athletes found that it is possible to experience cardiovascular benefits soon after the sedentary persons become physically active. This makes sense only in the light of evolution. With increasing performance level cardiovascular fitness is increased up to a point but then decreased in highly trained national athletes.
The non-invasive and simple echocardiographic test could be used to monitor exercise induced positive changes. This would help physicians in their efforts to promote the expansive benefits of exercise in all spectrums of society and encourage patients for doable and sustainable behavioral change.
Background
Human Endogenous Retroviruses (HERVs) are fossil viruses that composes 8% of the human genome and plays several important roles in human physiology, including muscle repair/myogenesis. It is believed that inflammation may also regulate HERV expression, and therefore may contribute in the muscle repair, especially after training exercise. Hence, this study aimed to assess the level of HERVs expression and inflammation profile in practitioners’ resistance exercises after an acute strength training session.
Methods
Healthy volunteers were separated in regular practitioners of resistance exercise training group (REG, n = 27) and non-trained individuals (Control Group, n = 20). All individuals performed a strength exercise section. Blood samples were collected before the exercise (T0) and 45 minutes after the training session (T1). HERV-K (HML1-10) and W were relatively quantified, cytokine concentration and circulating microparticles were assessed.
Results
REG presented higher level of HERV-W expression (~2.5 fold change) than CG at T1 (p<0.01). No difference was observed in the levels of HERV-K expression between the groups as well as the time points. Higher serum TNF-α and IL-10 levels were verified post-training session in REG and CG (p<0.01), and in REG was found a positive correlation between the levels of TNF-α at T1 and IL-10 at T0 (p = 0.01). Finally, a lower endothelial microparticle percentage was observed in REG at T1 than in T0 (p = 0.04).
Conclusion
REG individuals exhibited a significant upregulation of HERV-W and modulation of inflammatory markers when compared to CG. This combined effect could potentially support the process of skeletal muscle repair in the exercised individuals.
The effects of regular physical activity on two important anti-atherosclerosis functions of high-density lipoprotein (HDL), namely its capacity to receive both forms of cholesterol and its anti-oxidant function, were investigated in this study comparing older adults with young individuals. One-hundred and eight healthy adult individuals were enrolled and separated into the following groups: active older (60–80 yrs, n = 24); inactive older (60–79 yrs, n = 21); active young (20–34 yrs, n = 39); and inactive young (20–35 yrs, n = 24). All performed cardiopulmonary tests. Blood samples were collected in order to assess the following measures: lipid profile, HDL anti-oxidant capacity, paraoxonase-1 activity, HDL subfractions, and lipid transfer to HDL. Comparing active older and active young groups with inactive older and inactive young groups, respectively, the active groups presented higher HDL-C levels (p < 0.01 for both comparisons), unesterified cholesterol transfer (p < 0.01, p < 0.05), and intermediate and larger HDL subfractions (p < 0.001, p < 0.01) than the respective inactive groups. In addition, the active young group showed higher esterified cholesterol transfer than the inactive young group (p < 0.05). As expected, the two active groups had higher VO2peak than the inactive groups; VO2peak was higher in the two younger than in the two older groups (p < 0.05). No differences in unesterified and esterified cholesterol transfers and HDL subfractions were found between active young and active older groups. HDL anti-oxidant capacity and paraoxonase-1 activity were equal in all four study groups. Our data highlight and strengthen the benefits of regular practice of physical activity on an important HDL function, the capacity of HDL to receive cholesterol, despite the age-dependent decrease in VO2peak.
Scientific support is an essential component of long-term athletic development programmes designed to optimise the present and future sporting performance of elite youth athletes. Physiological assessment and monitoring require a clear rationale with due consideration of the ethics of the physiological testing of minors. It is the responsibility of the sport physiologist, in consultation with the coach and athlete, to identify the specific physiological determinants of the youth athlete’s sport, event(s), or role in a team, to select the appropriate physiological variables to examine, and to design an appropriate battery of ecologically valid laboratory-based physiological assessments and complementary field tests. The physical and physiological variables underpinning youth sport performance develop with sex-specific, concurrent changes in age, growth, and maturation controlled by individual biological clocks. Elite youth athletes might be prepubertal, mid-pubertal, or in late puberty, or have completed biological maturation and the sport physiologist needs to interpret longitudinal assessment data in relation to both developmental physiology and the elite performance demands of specific sports. Physiological assessment and monitoring do not take place in a vacuum and the relationship between the sport physiologist, other members of the scientific support team, coach, and youth athlete is an essential component of a successful scientific support programme. The success of the programme is promoted by prompt feedback of contextual data interpreted and discussed in relation to performance progression and communicated free of scientific jargon through platforms commonly used by coaches and youth athletes, including videos, infographics, and audio presentations.
Havacılık, otomotiv ve beyaz eşya gibi sektörlerde delik delme talaşlı ve talaşsız imalatın büyük çoğunluğunu oluşturur. Bu sektörlerde kullanılan metal aksamların üretilmesi esnasında yüzlerce delik delinmektedir. Özellikle ocak gibi ev eşyalarının metal parçalarında 1-5 mm gibi küçük çaplarda zımbalar kullanılarak delik elde edilmektedir. Yüksek üretim adetleri ve üretim proseslerinde karşılaşılan problemler sebebi ile bu zımbalar aşınmaktadır. Seri üretim esnasında aşınan zımbalar delinen deliklerde çapaklanmaya, ölçüsel farklılıklara ve üretim duruşlarına sebebiyet vermektedir. Bu sebeplerden dolayı delik delme ve kesme zımbalarının dayanımlarının arttırılması amacı ile tavlama, normalleştirme, su verme, temperleme, tavlama, yaşlandırma, karbürleme, nitrürleme ve kriyojenik işlem gibi uygulamalar yapılmaktadır. Bu yöntemlerden kriyojenik işlem ile kesme zımbalarının mikroyapısının iyileştiği, homojen karbür dağılımı ve ince taneli martensit yapıya dönüşmesi sayesinde sertlik, tokluk, aşınma direnci gibi birçok özelliklerinin iyileştiği bilinmektedir. Bu çalışmada ankastre ocakların metal parçalarının delinmesinde kullanılan Ø3 mm zımbalara 36 saat kriyojenik işlem ve 500 °C temperleme parametrelerinde kriyojenik işlem uygulanarak sertlik değişimleri incelenmiştir. Kriyojenik işlem uygulanan ve referans olarak işlemsiz seçilen üçer adet zımbanın makro, mikro analizleri sonrası sertlik ölçümleri yapıldıktan sonra kriyojenik işlemli zımbaların mekanik özelliklerinin iyileştiği tespit edilmiştir. Sertlik ölçüm sonuçlarına göre kriyojenik işlem görmüş zımbaların ortalama sertlik değerleri 774 HV0.3 ‘dan 801 HV0.3 değerine yükselerek % 3.37 artmıştır. Delik elde etmek için kullanılan zımbalara uygulanan kriyojenik işlemin malzeme mikro yapısını olumlu etkilediği ve seri üretimde zımba hasarlarının azaltılmasında avantaj sağlayacağı düşünülmektedir.
Beyaz eşya sektöründe yüksek üretim adedine sahip fırın ve ocaklar büyük oranda metal parçalardan oluşurlar. Özellikle dış kasa ve dayanım gerektiren parçaların bir çoğu metal malzemelerden imal edilmektedir. Bu parçaların kullanım yerlerine montaj edilebilmesi veya diğer ekipmanların bu parçalara sabitlenebilmesi için üzerlerine delik oluşturmak gerekir. Seri üretime uygunluk ve ölçüsel hassasiyet söz konusu olduğu için delik delme işlemleri hidrolik veya eksantrik preslerde sac ve metal kalıplar kullanılarak yapılmaktadır. Delme kalıplarında kullanılan delik delme zımbalarının ısı ve sürtünmeye karşı dirençli, sarma ve soğuk kaynak gibi etkilere karşı dayanıklı olması istenir. Bu sebeple delik delme zımbaları olarak sinterli karbür, toz metal ve titanyum nitrür kaplamalı gibi çeşitler tercih edilmektedir. Bu çalışmada ise 1.3343 HSS malzemeden imal edilen titanyum nitrür kaplı zımbalara 36 saat kriyojenik işlem ve 200 °C temperleme parametrelerinde kriyojenik işlem uygulanmıştır. Deneylerde kullanılan zımbaların kriyojenik işlem öncesi ve sonrası SEM, EDS analizleri yapılarak mikro ve makro görüntüleri elde edilmiştir. Ayrıca her bir zımbanın sertlik değerleri ölçülerek aritmetik ortalamalar tespit edilmiştir. Yapılan ölçümler neticesinde kriyojenik işlem görmüş zımbaların ortalama sertlik değerleri 774 HV0.3 ‘dan 792 HV0.3 değerine yükselerek % 2.32 artmıştır. Bu artışın mikroyapıda kalan ve yumuşak faz olan östenitin, sert faz olan martenzite dönüşmesinden kaynaklandığı düşünülmektedir. Ayrıca kriyojenik işlem ve temperleme uygulanması sonrası malzeme mikroyapısında ikincil sert karbür yapılarının çökelmesinin ortalama sertlik değerlerini arttırdığı düşünülmektedir.
Os objetivos deste estudo foram: (i) analisar os estereótipos de género dos alunos em relação à prática de atividade física e desportiva, (ii) conhecer a valorização dos pais e das mães sobre estes mesmos estereótipos. Participaram 478 alunos e alunas, 434 pais e mães da Galiza (Espanha). Utilizou-se como instrumento de recolha de dados o questionário sobre o Estilo de vida desportiva em relação ao género. Um teste do qui-quadrado foi realizado para avaliar a associação entre as variáveis género, nível de escolaridade e opinião dos alunos e dos pais/responsáveis; e V de Cramer para quantificar o grau de associação entre as variáveis. Os resultados sugerem que o género é cada vez menos segregador, registando-se uma evolução da superação de estereótipos relacionados com o desporto. Contudo, continuam a existir estereótipos como a crença de que há desportos para rapazes e para raparigas. Destaca-se o papel da família como agente socializador de condutas não sexistas relacionadas com o desporto e com o facto de que o género masculino seja mais resistente.
BACKGROUND: The aim of this study was to investigate front crawl technique and performance in children using kinematic variables in a 50-m maximum (T50) test.
METHODS: Thirty-five children performed the T50, from which images were obtained of the two 25-m laps (L1 and L2) by 2 synchronized cameras and processed with Kinovea software (Kinovea Org., San Francisco, CA, USA).
RESULTS: Comparisons between L1 and L2 revealed that the index of coordination (IdC: -4.4±4.4; -4.7±3.7%); stroke length (SL: 1.37±0.20; 1.39±0.32 m) and duration of entry and catch (32.1±6.7; 33.2±7.5%), pull (15.7±3.2; 16.5±3.7%), push (25.9±6.1; 26.1±6.1%) and recovery stroke phases (26.3±6.1; 24.2±6.0%) remained constant. The stroke rate (SR: 53.9±6.1; 46.8±6.7 cycles·min-1) and mean swimming speed (SS: 1.22±0.13; 1.06±0.17 m·s-1) were reduced, and the propulsive time (Tprop: 18.2±3.5, 21.3±5.5 s) increased. Significant correlations were found between performance and SL and Tprop (r=-0.72, P=0.010; and r=0.53, P=0.022, respectively).
CONCLUSIONS: SR, SS and Tprop were modified during the T50 in the front crawl in children, indicating technique variation, even in a short-distance event.
Introduction
Prolonged time trials proved capable of precisely estimating anaerobic threshold. However, time trial studies in recreational cyclists are missing. The aim of the present study was to evaluate accuracy and viability of constant power threshold, which is the highest power output constantly maintainable over time, for estimating maximal lactate steady state in recreational athletes.
Methods
A total of 25 recreational athletes participated in the study of whom 22 (11 female, 11 male) conducted all constant load time trials required for determining constant power threshold 30 min and 45 min, which is the highest power output constantly maintainable over 30 min and 45 min, respectively. Maximal lactate steady state was assessed subsequently from blood samples taken every 5 min during the time trials.
Results
Constant power threshold over 45 min (175.5 ± 49.6 W) almost matched power output at maximal lactate steady state (176.4 ± 50.5 W), whereas constant power threshold over 30 min (181.4 ± 51.4 W) was marginally higher ( P = 0.007, d = 0.74). Interrelations between maximal lactate steady state and constant power threshold 30 min and constant power threshold 45 min were very close (R ² = 0.99, SEE = 8.9 W, Percentage SEE (%SEE) = 5.1%, P < 0.001 and R ² = 0.99, SEE = 10.0 W, %SEE = 5.7%, P < 0.001, respectively).
Conclusions
Determination of constant power threshold is a straining but viable and precise alternative for recreational cyclists to estimate power output at maximal lactate steady state and thus maximal sustainable oxidative metabolic rate.
GİRİŞ Sporcuların mevcut spor branşlarındaki başarısını etkileyen önemli faktörlerden biri o spor branşının gerektirdiği fiziksel ve fizyolojik özelliklere sahip olabilmektir.(1) Her spor branşının kendine özgü birtakım özellikleri mevcuttur. Branşların gerektirdiği fiziksel ve fizyolojik özellikleri bilmek sporcuların performans gelişimine katkı sağlamaktadır. Branşın gerektirdiği özellikleri bilmek; spor elamanlarına, antrenörlere, spor bilimcilere antrenman programı yazma ve planlama konusunda, sporcuların gelişimlerini takip etmekte yardımcı unsurdur. Bunun doğrultusunda spor bilimciler, antrenörler, spor yöneticileri fiziksel, psikolojik, antropometrik ve teknik kriterleri kullanarak şampiyon adaylar seçme ve yetiştirmeye çalışmaktadırlar.(2) Sporcunun performans durumundan söz edebilmek için branşa özgü birkaç parametreyi veya tüm parametreleri tanımlamak gerekmektedir.(3) Her branş kendine özgü teknik ve zihinsel becerinin yanı sıra temel-spesifik özellikleri barındırmaktadır. Badminton uzun süren, yorucu bir branştır. Badminton branşının genel özelliği, doğası gereği kısa veya uzun rallilerin yapılması, kısa dinlenme süresinin olması ve yüksek yoğunluklu aktiviteler içermesidir. Ralli esnasında hızlı bir hamlenin yapılması, ani dönüş ve sonrasında başka bir yöne doğru hareket edilmesi, patlayıcı kas gücüne maç boyunca ihtiyaç olduğunu göstermektedir. Bu nedenle de alt ekstremite kas yapısı badminton branşında önem arz etmektedir. Badminton branşı dayanıklılık, hız, güç, kuvvet, çeviklik, denge, koordinasyon gibi temel 1
Antropometrik ve fizyolojik özellikler gibi fiziksel yeteneklere sahip olmak, herhangi bir yarışmaya veya turnuvaya karşı başarı için ön koşuldur. Branşa özgü biyomotor yetiler sporcu performansını etkileyen faktörlerden biridir. Belirlenmiş hedeflere ulaşmak, doğru ve etkili bir antrenman programı hazırlayabilmek için normatif verilere ihtiyaç duyulmaktadır. Bu doğrultuda, Türk taekwondosunda ki sporcuların normlandırmasını yaparak, sporcu seçimi yapacak olan antrenörlere, spor elemanlarına yol göstermek ve bu konuda yapılacak çalışmalara katkıda bulunmak amaçlanmıştır. Bu amaç doğrultusunda, Türkiye genelinde taekwondo çalışan, mavi kuşak ve üstü kuşak derecesine sahip 650 sporcunun belirlenmiş ölçütlerdeki normatif çalışması Ocak 2020-Mart 2020 tarihleri arasında yapılmıştır. Araştırma grubundaki sporcuların boy uzunluğu, vücut ağırlığı, vücut kitle indeksi, 20 m. sürat koşusu, squat sıçrama, aktif sıçrama, serbest kol sıçrama, sağ ve sol el kavrama kuvveti, sağlık topu atma, gövde mekik testi ve branşa özgü teknik vuruşların ölçümleri yapılmış, belirlenen yaş kategorileri ve cinsiyetler için incelenen değişkenlerinin ortalama, standart sapma ve yüzdelik değerleri sunularak normlar oluşturulmuştur. Ayrıca sporcular cinsiyet, yaş grupları ve kuşaklarına göre kendi içinde karşılaştırılmış, benzerlik ve farklılıklar ortaya konmuştur. Antropometrik özellikler yaşa göre incelendiğinde oturma boyu yüksekliği hariç diğer özelliklerde farklılığa rastlanmamışken biyomotor özellikler cinsiyete göre karşılaştırıldığında denge, 10m-20m sürat parametreleri hariç diğer tüm parametrelerin istatiksel olarak anlamlı olduğu gözlenmiştir. Esneklik hariç diğer parametrelerde erkekler lehine fark gözlemlenirken esneklik parametresinde kızlar lehine anlamlı bir farklılık belirtilmiştir. Taekwondo vuruşları cinsiyete göre karşılaştırıldığında sağ puşe chagi tekniği hariç diğer parametrelerde erkek lehine istatiksel olarak anlamlı bir fark tespit edilmiştir.
Background: It is often advised to ensure a high protein intake during energy-restricted diets. However, it is unclear whether a high protein intake is able to maintain muscle mass and contractility in the absence of resistance training.
Materials and Methods: After 1 week of body mass maintenance (45 kcal/kg), 28 male college students not performing resistance training were randomized to either the energy-restricted (ER, 30 kcal/kg, n = 14) or the eucaloric control group (CG, 45 kcal/kg, n = 14) for 6 weeks. Both groups had their protein intake matched at 2.8 g/kg fat-free-mass and continued their habitual training throughout the study. Body composition was assessed weekly using multifrequency bioelectrical impedance analysis. Contractile properties of the m. rectus femoris were examined with Tensiomyography and MyotonPRO at weeks 1, 3, and 5 along with sleep (PSQI) and mood (POMS).
Results: The ER group revealed greater reductions in body mass (Δ -3.22 kg vs. Δ 1.90 kg , p < .001, partial η² = .360), lean body mass (Δ -1.49 kg vs. Δ .68 kg, p < .001, partial η² = .152), body cell mass (Δ -.85 kg vs. Δ .59 kg, p < .001, partial η² = .181), intracellular water (Δ -.58 l vs. Δ .55 l, p < .001, partial η² = .445) and body fat percentage (Δ -1.74 % vs. Δ 1.22 %, p < .001, partial η² = 433) compared to the CG. Contractile properties, sleep onset, sleep duration as well as depression, fatigue and hostility did not change (p > .05). The PSQI score (Δ -1.43 vs. Δ -.64, p = .006, partial η² = .176) and vigor (Δ -2.79 vs. Δ -4.71, p = .040, partial η² = .116) decreased significantly in the ER group and the CG, respectively.
Discussion: The present data show that a high-protein intake alone was not able to prevent lean mass loss associated with a 6-week moderate energy restriction in college students. Notably, it is unknown whether protein intake at 2.8 g/kg fat-free-mass prevented larger decreases in lean body mass. Muscle contractility was not negatively altered by this form of energy restriction. Sleep quality improved in both groups. Whether these advantages are due to the high-protein intake cannot be clarified and warrants further study. Although vigor was negatively affected in both groups, other mood parameters did not change.
Background:
Monitoring technical performance during a soccer match has become an indispensable practice, since the players perform different functions within the tactical system adopted by the team, resulting in specific technical actions that are fully responsive to the individual technical level of each player. Thus, current study aimed to investigate the possible direct and mediating relationship between salivary testosterone and the technical performance of semi-professional footballers during a training game.
Methods:
To characterize the sample, the anthropometric profile, body composition, biological maturation, lower limb power, speed, estimation of maximum oxygen consumption, and physical performance were used. To determine testosterone concentrations, saliva was collected before and after the training game, for subsequent measurement using enzyme immunoassay (ELISA) and Salimetrics Kits. For quantification of technical performance and participation with the ball during the training game, scout software was used from the footage of the training game. The reliability of the technical performance analyses was determined through the repetition test of two attempts (Cohen's Kappa agreement index).
Results:
The direct relationship between post-game testosterone and total participation with the ball in the second half; the direct relationship between the percentage of lean mass with post-game testosterone and an apparent relationship between percentage of lean mass and total participation with the ball from the set of relations mediated by post-game testosterone concentrations.
Conclusions:
The results suggest that testosterone concentrations combined with high levels of lean mass may have a important role in the technical performance and participation with the ball of semi-professional footballers.
Introduction
A year after the emergence of a novel coronavirus, SARS-CoV-2, as a new crisis in respiratory infections, there remain many uncertainties and unknowns about SARS-CoV-2 and the disease it causes, COVID-19. Although COVID-19 is known as respiratory disease, some atypical manifestations have been seen, different from those seen in other types of viral respiratory infections. This paper aims to describe designing, launching, and implementing a data collection system for all respiratory diseases, with a focus on SARS-CoV-2 from the onset of this pandemic.
Method
The current registry is designed in compliance with the standard Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines, along with the declaration of Helsinki principles.
Results
A respiratory disease registry, with an emphasis on COVID-19 and other co-infections, was developed. Data consisted of demographic, clinical, and supporting information about SARS-CoV-2 and other respiratory viral diseases.
Conclusion
It is hoped that the current data registry will facilitate patient evaluation and improve the outcomes of cases of respiratory infection defined by a particular condition, disease, or exposure. Moreover, the registry can harmonize data about the treatment, outcomes, and well-being of patients who receive care over time, and identify best practices.
Speed and agility are crucial abilities in many team sports such as soccer, basketball or handball. Therefore determing factors affect speed abilities is relevant. To investigate multidimensional correlations of the FMS test results with speed abilities. 35 male team sport players, aged 21.31±0.93. Body weight and body height were measured and BMI was calculated (kg/m2). Three modules of the FMS test were used to analyse: Deep Squat, Hurdle Step, In-line Lunge. Linear speed was measured based on the 20m Linear Speed test, agility was evaluated using the Agility T-test. Data were analysed by Canonical Correlation Analysis (CAA). The CCA analysis demonstrated statistically significant correlation between morphological features and agility. Correlation was found between 20m Linear Speed and In-line Lunge. However it was not revealed any significant correlations of neither speed skills nor morphological characteristics with chosen FMS subtests. High canonical loadings and weights suggested the presence of correlations (not significant) between individual measurements. The correlations between morphological measurements and functional movement were very close to statistical significance. The CCA analysis allowed for showing multivariate links between morphological features and functional abilities. This results demonstrated moderate correlations between body morphology and agility and between movement patterns and agility. Better scores in agility were correlated with good performance in In-line Lunge and Hurdle Step test.
As intensity and physical demands continue to rise in sport competition, faster and better recovery becomes essential. The aim of this study was to assess the effects of HRV biofeedback (HRVB) while recovering from a submaximal aerobic exercise. Ten physically-active graduate students participated in the study, which was conducted in four sessions: exercise with free-breathing recovery, first resonance frequency (RF) detection, second RF detection, and exercise applying HRVB during recovery. Measurements included time spent running and recovering, HRV parameters, and recovery/exertion perceptions. The results indicate that using HRVB during recovery improves cardiac variability (RRmean, SDNN, RMSSD and LF; p < 0.01). HRVB also lowers recovery time ( p < 0.05) and seems to be improving the perception of recovery ( p = 0.087). Moreover, time spent exercising ( p < 0.01) and perceived physical exertion ( p < 0.05) were higher when applying HRVB. The improvement in the psychophysiological adaptation after intensive aerobic exercise provided by the HRVB is a valuable benefit, not only for competition-driven athletes, but also for the general population.
Introducción: Estimar la fuerza muscular en miembros superiores con diferentes pruebas es primordial para la cuantificación de las cargas de entrenamiento, sin embargo, son escasos los estudios científicos que correlacionan las flexiones de brazos con la repetición máxima en press banca plano, un ejercicio de peso libre comúnmente utilizado para activar la musculatura del tren superior.
Objetivo: Determinar la asociación entre la resistencia muscular en flexiones de brazos y la repetición máxima en press banca plano en sujetos físicamente activos.
Métodos: Estudio descriptivo de tipo correlacional con una muestra a conveniencia de 15 hombres y 7 mujeres estudiantes de educación física, recreación y deportes de la Universidad de Pamplona. Se aplicó el protocolo de la National Strength and Conditioning Association para la evaluación de la resistencia muscular en flexiones de brazo y para el press banca plano se aplicó el test de la repetición máxima que consiste en ejecutar una repetición con la mayor cantidad de peso posible. Se utilizó el paquete estadístico PSPP (p-valor de 0,05) para aplicar las pruebas de normalidad (Shapiro-Wilk) y el coeficiente de correlación de Spearman.
Resultados: El principal hallazgo fue la asociación positiva y no significativa (p > 0,05) de la resistencia muscular en flexiones de brazos con la repetición máxima en press banca plano en hombres (r = 0,26) y mujeres (r = 0,49).
Conclusión: En sujetos físicamente activos no existe una asociación significativa entre la resistencia muscular en flexiones de brazo y la repetición máxima en press banca plano.
La distancia que recorren los jugadores por partido supone una forma de cuantificar el volumen de carga externa del juego, y su estudio tiene una gran aplicación en la planificación del entrenamiento deportivo. El objetivo de este estudio fue analizar la distancia recorrida en diferentes fases del partido (activa y pasiva) y su relación con el número de puntos disputados y nivel de juego de los deportistas. La muestra estuvo compuesta por 108 jugadores federados de pádel (edad media = 33.81 ± 6.72 años). Se analizaron, a través de observación sistemática con el sistema SAGIT, un total 4406 puntos correspondientes a 27 partidos de pádel. Los partidos fueron divididos en tres niveles de competición: nivel alto (9 partidos; 1158 puntos), nivel medio (9 partidos; 1352 puntos) y nivel bajo (9 partidos; 1044 puntos). Los resultados mostraron como los jugadores de pádel recorren una distancia media de 11 metros por punto y de 2900 metros por partido. Esta distancia total está dividida en un 51 % de fase activa (tiempo de juego) y un 49 % de fase pasiva (tiempo de descanso). Los jugadores de nivel medio recorrieron casi 400 metros más en la fase activa que los jugadores de nivel alto y casi 900 metros más que los jugadores de nivel bajo. Además, el número de puntos disputados correlacionó de forma positiva y significativamente en la distancia recorrida por los jugadores. Abstract. Volume of game external load can be calculated through distance covered by players per match and its study has a great application in the planning of sports trainings. The aim of this study was to analyze distance covered in passive and active game phases and its relation with number of points played and players’ level. Sample was made up of 108 federated padel players (Average age = 33.81 ± 6.72 years old). A total of 4406 points corresponding to 27 padel matches were analyzed through systematic observation with the SAGIT system. Matches were divided into three levels of competition: high level (9 matches; 1158 points), medium level (9 matches; 1352 points) and low level (9 matches; 1044 points). The results showed that padel players covered an average distance of 11 meters per point and 2900 meters per game. This total distance is divided into 51% active phase (playing time) and 49% passive phase (rest time). The mid-level players recorded almost 400 meters more in the active phase than the high-level players and almost 900 meters more than the low-level players. In addition, number of points correlated positively and significantly with the distance covered by the players.
To date two main techniques are used in arthroscopic full-thickness rotator cuff tears, the conventional knot-tying suture bridge technique and the knotless technique. We evaluated whether there is a difference in clinical outcome using both techniques. Our patients underwent arthroscopic treatment of full-thickness rotator cuff tears, and we retrospectively evaluated clinical function, strength and surgery time. Eighty-three shoulders operated between September 2012 and December 2013 were included in the study. We had nineteen patients in the knotless group, and sixty-four in the knot-tying group. In addition, we performed preoperatively radiological (magnetic resonance imaging-MRI) conformation of full-thickness rotator cuff tear in our patients. For clinical evaluation, we used Quick Disabilities of the Arm, Shoulder and Hand score (q-DASH) and the Shoulder Pain and Disability (SPADI) score, and we measured the strength of a range of motion postoperatively using a conventional dynamometer. The patients were evaluated preoperatively, and at 6, 9, and 12 months postoperatively. The follow-up period was 12 months. The scores in both treatment groups improved at twelve months follow-up, but there was no statistical difference between both groups at twelve months after surgery; q-DASH score between groups (p = 0.092) and SPADI score (p = 0.700). Similarly, there was no statistical difference between the groups in regard to strength, surgery time, and range of motion at the twelve months follow-up. Our data confirm that both techniques may be used successfully to repair full-thickness rotator cuff tears with very good functional outcome.
Level of evidence IV.
Resumo: O caráter pedagógico das práticas esportivas tem sido motivo de diversos estudos no contexto da Pedagogia do Esporte, na qual os conteúdos socioeducativos começam a ganhar destaque. A fim de contribuir para a aproximação entre a teoria e a prática, este estudo foi realizado com o objetivo de investigar como professores de projetos socioesportivos desenvolvem os conteúdos socioeducativos. Dois projetos socioesportivos foram a fonte para responder essa questão. Esta pesquisa é caracterizada como de campo, transversal, qualitativa, na qual se utilizaram como técnicas de pesquisa a análise documental, a entrevista semiestruturada e a observação não participante. Os resultados apresentam o diálogo como o método mais utilizado pelos professores no desenvolvimento de questões socioeducativas, enquanto as atividades esportivas não tiveram esse enfoque intencional. Portanto, sugere-se a produção de estudos aplicados que objetivem uma melhor e maior aproximação entre a teoria e a prática no desenvolvimento dos conteúdos socioeducativos.
The resulting muscular performance is considered notably higher during a stretch shortening cycle (SSC) compared to an isolated concentric contraction. Thus, the present study examined the occurrence and magnitude of rowing performance enhancement after a flexion–extension cycle (FEC) of the legs compared to both concentric contractions only and isometric pre-contraction. Therefore, 31 sub-elite male rowers (age: 25 ± 6 years, height: 1.90 ± 0.02 m, weight: 91 ± 10 kg, weekly training volume: 11.4 ± 5.3 h/week, rowing experience: 7.1 ± 2.7 years) randomly completed (a) isolated concentric rowing strokes (DRIVE), (b) single FEC-type rowing strokes (SLIDE-DRIVE), and (c) rowing strokes with an isometric pre-contraction (ISO-DRIVE). The resulting rowing power (Prow), leg power (Pleg), and work per stroke (WPS) were recorded using motion-capturing, force, and rotation sensors. Comparison of DRIVE and SLIDE-DRIVE revealed significantly (p < 0.05) higher Prow (+11.8 ± 14.0%), Pleg (+19.6 ± 26.7%), and WPS (+9.9 ± 10.5%) during SLIDE-DRIVE. Compared to ISO-DRIVE, Pleg (+9.8 ± 26.6%) and WPS (+6.1 ± 6.7%) are again significantly (p < 0.05) higher for SLIDE-DRIVE. In conclusion, notably higher work and power outputs (compared to an isolated concentric contraction) during FEC rowing referred to an underlying SSC. Future ultrasound studies should elucidate whether a real SSC on the muscle tendon unit level account for these performance enhancements.
The consideration of the temporal and electromyographic (EMG) characteristics of stretch-shortening cycles (SSC) are crucial for the conceptualization of discipline-specific testing and training. Since leg muscles are first stretched (eccentric) and then contracted (concentric) during rowing, it can be assumed that the entire muscle tendon complex performs a SSC. Thus, it should be elucidated whether the rowing cycle can be attributed to either a slow or fast SSC. Therefore, EMG of the vastus medialis and gastrocnemius were captured (n = 10, 22.8 ± 3.1 years, 190 ± 6 cm, 82.1 ± 9.8 kg) during (single scull) rowing and subsequently compared to typical slow (countermovement jump, CMJ) and fast (drop jump, DJ) SSCs. The elapsed time between the EMG onset and the start of the eccentric phase was monitored. The pre-activation phase (PRE, before the start of the eccentric phase) and the reflex-induced activation phase (RIA 30–120 ms after the start of the eccentric phase) have been classified. Notable muscular activity was observed during DJ before the start of the eccentric phase (PRE) as well as during RIA. In contrast, neither CMJ nor rowing revealed any EMG-activity in these two phases. Interestingly, CMJ and race-specific rowing showed an EMG-onset during the eccentric phase. We conclude that rowing is more attributable to a slow SSC and implies that fast SSC does not reflect discipline specific muscle action and could hamper rowing-performance-enhancement.
Análisis de la distancia recorrida en pádel en función del nivel de juego y el número de puntos por partido Analysis of distance covered in padel regarding level of play and number of points per match Resumen. La distancia que recorren los jugadores por partido supone una forma de cuantificar el volumen de carga externa del juego, y su estudio tiene una gran aplicación en la planificación del entrenamiento deportivo. El objetivo de este estudio fue analizar la distancia recorrida en diferentes fases del partido (activa y pasiva) y su relación con el número de puntos disputados y nivel de juego de los deportistas. La muestra estuvo compuesta por 108 jugadores federados de pádel (edad media = 33.81 ± 6.72 años). Se analizaron, a través de observación sistemática con el sistema SAGIT, un total 4406 puntos correspondientes a 27 partidos de pádel. Los partidos fueron divididos en tres niveles de competición: nivel alto (9 partidos; 1158 puntos), nivel medio (9 partidos; 1352 puntos) y nivel bajo (9 partidos; 1044 puntos). Los resultados mostraron como los jugadores de pádel recorren una distancia media de 11 metros por punto y de 2900 metros por partido. Esta distancia total está dividida en un 51 % de fase activa (tiempo de juego) y un 49 % de fase pasiva (tiempo de descanso). Los jugadores de nivel medio recorrieron casi 400 metros más en la fase activa que los jugadores de nivel alto y casi 900 metros más que los jugadores de nivel bajo. Además, el número de puntos disputados correlacionó de forma positiva y significativamente en la distancia recorrida por los jugadores. Palabras clave: Deportes de raqueta, rendimiento, carga externa, movimientos, ritmo de trabajo. Abstract. Volume of game external load can be calculated through distance covered by players per match and its study has a great application in the planning of sports training. The aim of this study was to analyze distance covered in passive and active game phases and its relation with number of points played regarding players' level. Sample was made up of 108 federated padel players (Average age = 33.81 ± 6.72 years old). A total of 4406 points corresponding to 27 padel matches were analyzed through systematic observation with the SAGIT system. Matches were divided into three levels of competition: high level (9 matches; 1158 points), medium level (9 matches; 1352 points) and low level (9 matches; 1044 points). The results showed that padel players covered an average distance of 11 meters per point and 2900 meters per game. This total distance is divided into 51% active phase (playing time) and 49% passive phase (rest time). The mid-level players recorded almost 400 meters more in the active phase than the high-level players and almost 900 meters more than the low-level players. In addition, number of points correlated positively and significantly with the distance covered by the players.
Los objetivos de este estudio fueron: (i) analizar los estereotipos de género presentes en alumnado en relación con la práctica de actividad físico-deportiva y, (ii) conocer la valoración de las madres y los padres con respecto a los mismos estereotipos. Participaron 478 alumnos y alumnas y, 434 padres y madres de Galicia (España). Como instrumento de recogida de datos, se utilizó el cuestionario de Estilo de vida deportiva con perspectiva de género. Se realizó una prueba de chi- cuadrado para valorar la asociación entre las variables de género, nivel educativo y opinión del alumnado y de los progenitores/tutores; y la V de Cramer para cuantificar el grado de asociación entre las variables. Los resultados sugieren que el género cada vez segrega menos, produciéndose una evolución hacia la superación de estereotipos en torno al deporte. No obstante, siguen persistiendo estereotipos como la creencia de que hay deportes para chicos y para chicas. Se destaca el papel de la familia como agente socializador en conductas no sexistas en torno al deporte y el hecho de que el género masculino sea más resistente al cambio.
Marked adaptation of left ventricular (LV) structure in endurance athletes is well established. However, previous investigations of functional and mechanical adaptation have been contradictory. A lack of clarity in subjects’ athletic performance level may have contributed to these disparate findings. This study aimed to describe structural, functional and mechanical characteristics of the cyclists’ LV, based on clearly defined performance levels. Male elite cyclists (EC) (n=69), sub‐elite cyclists (SEC) (n=30), and non‐athletes (NA) (n=46), were comparatively studied using conventional and speckle tracking 2D echocardiography. Dilated eccentric hypertrophy was common in EC (34.7 %), but not SEC (3.3 %). Chamber concentricity was higher in EC compared to SEC (7.11±1.08 g/(ml)2/3 vs 5.85±0.98 g/(ml)2/3, P<0.001). Ejection fraction (EF) was lower in EC compared to NA (57±5 % vs 59±4 %, P<0.05), and reduced EF was observed in a greater proportion of EC (11.6 %) compared to SEC (6.7 %). Global circumferential strain (GCε) was greater in EC (‐18.4±2.4 %) and SEC (‐19.8±2.7 %) compared to NA (‐17.2±2.6 %) (P<0.05 and P<0.001). Early diastolic filling was lower in EC compared to SEC (0.72±0.14 cm/s vs 0.88±0.12 cm/s, P<0.001), as were septal E’ (12±2 cm/s vs 15±2 cm/s, P<0.001) and lateral E’ (18±4 cm/s vs 20±4 cm/s, P<0.05). The magnitude of LV structural adaptation was far greater in EC compared to SEC. Increased GCε may represent a compensatory mechanism to maintain stroke volume in the presence of increased chamber volume. Decreased E and E’ velocities may be indicative of a considerable functional reserve in EC.
Os instrutores de aulas de grupo de fitness devem adequar o seu comportamento de feedback à preferência dos praticantes, promovendo aprendizagem, motivação, satisfação e, consequentemente, adesão ao exercício (Franco & Simões, 2017). O objetivo deste estudo foi caracterizar a preferência dos idosos, em aulas de hidroginástica, relativamente ao comportamento de feedback dos instrutores. A amostra foi composta por 218 idosos. Aplicou-se o Questionário Feedback dos Instrutores de Fitness (Simões, Rodrigues, Alves & Franco, 2013). Verificou-se que os idosos preferem que os instrutores emitam feedback: direcionado para toda a classe, informando a forma de realizar o exercício, referindo-se à respiração, sobre um exercício de cada vez, utilizando a forma verbal, durante a realização do exercício e com o instrutor perto do praticante, a realizar o mesmo exercício e de frente para os praticantes, demonstrando afetividade positiva, sendo que depois do instrutor emitir feedback fique a observar e seguidamente emita novo feedback.
Ethical evaluation is a vital but sometimes neglected component of research policy in the exercise sciences. This article reviews some issues in human research, with particular reference to studies undertaken by the exercise scientist. The typical composition and functions of the research review committee are examined in the context of individual and institutional ethical norms. In multicentre trials, there are often problems in coordinating ethical approval between institutions. On-going monitoring of research may have value in the detection of fraud. A reduction in the secrecy of committee proceedings would allow a closer auditing of the research review process. Authors need to give more thought to developing appropriate research questions. Scarce resources may be wasted because of inappropriate study design or an inadequate statistical analysis of the results. The costs of any proposed investigation must be weighed carefully against possible benefits. Confidentiality is particularly important when collecting data at the worksite or over the internet. Informed consent should be based on a full disclosure of risks; the participant should be competent to understand the nature and magnitude of these risks, and undue pressure to participate in an experiment must be avoided. The opposition to placebo trials expressed in the Declaration of Helsinki requires careful consideration of the use of control groups, since regular exercise is known to benefit health. If research is conducted in under-developed societies, the standards of treatment of the participants should match those expected in developed societies. The publication of findings must be fair and well balanced; examples of fraud and misconduct continue to be reported. Some journals apparently still publish papers, even if they have not received an initial institutional review. Editors should restore meaning to the word 'author', avoid the bias to a publication of 'positive' results, limit the impact of commercial sponsorship on reporting and curtail the current trend to redundant presentations and publications. Development of academic courses in research ethics may help to avoid some of these abuses.
World Medical Association Available at http:// www.wma.net/e/ethics unit/helsinki.htm 2 Institute for Laboratory Animal Research, National Research Council. Guide for the Care and Use of Laboratory Animals
- Helsinki Declaration
Declaration of Helsinki. World Medical Association. Available at http://
www.wma.net/e/ethics unit/helsinki.htm
2 Institute for Laboratory Animal Research, National Research Council.
Guide for the Care and Use of Laboratory Animals. Washington, D.C.:
National Academy Press ; 1996 ; 140
MRC ethics series: Good research practice
- Medical Research
- Council
Medical Research Council. MRC ethics series: Good research practice
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