Archivos de medicina del deporte: revista de la Federación Española de Medicina del Deporte y de la Confederación Iberoamericana de Medicina del Deporte, 2020
ABSTRACT Background: Previous studies on soccer small-sided games (SSGs) chose between with and w... more ABSTRACT Background: Previous studies on soccer small-sided games (SSGs) chose between with and without offside rule conditions without evidence-based criteria. The current study aimed to compare the positional dynamics of 3v3 SSGs with and without the offside rule. Methods: Twenty-four Brazilian U-17 national-level soccer players were recruited. They were split into eight teams and played SSGs with and without the offside rule . Positional data were gathered by a Global Positioning System, and teams’ length, width, the length per width ratio (LPWratio), stretch index and players’ spatial exploration index were calculated. Data were compared between the experimental conditions by a paired t-test. Results: Results showed that SSGs with the offside rule presented lower values of length (~16.63%, large effect), the LPWratio (~19.74%, large effect), and players’ spatial exploration (~4.13%, small-to-moderate effect). Conclusion: We conclude that the offside rule impacts players’ positional behavior in SSGs, inducing a less exploratory behavior mainly in the width axis. For this reason, we recommend caution when interpreting previous results on SSG when the offside rule was not applied since adopting this rule might elicit different responses to the players . Coaches can manipulate this rule aiming to achieve specific tactical goals for the training session.
Muscle volume (MV) and anatomical cross-sectional area (CSA) are used as measures of muscle-size,... more Muscle volume (MV) and anatomical cross-sectional area (CSA) are used as measures of muscle-size, but determining these from magnetic resonance imaging (MRI) is a very time-consuming process. Additionally, it is unclear if the use of different muscle size assessments (all vs. reduced number of slices images) would impact the muscle size-strength relationship. Thus, this study aimed to investigate if muscle size calculation by using a reduced or all slices images from pectoralis major (PM) would maintain a similar muscle size-strength relationship with bilateral maximal dynamic and isometric contractions on a bench press exercise. Twenty-four healthy males underwent an MRI examination to measure PM muscle size, and maximal isometric and dynamic contractions (by one repetition maximum, 1RM) were performed. Correlations between maximal isometric voluntary force (MVF) and dynamic strength (1RM) with muscle size variables [three images from the largest part of PM (CSA3MAX), three images accounting for the shape -first image, middle image, final image- of the PM (CSA3), and MV] were performed. The correlation between 1RM with MV, CSA3, and CSA3MAX were 0.84, 0.832, and 0.727 (p < 0.001), respectively. The correlation between MVF with MV, CSA3, and CSA3MAX were 0.738, 0.733, and 0.604 (p < 0.001), respectively. Overall, PM MV and CSA3 exhibit a stronger and similar muscle size-strength relationship during maximal dynamic and isometric tests than CSA3MAX. Therefore, a reduced number of slices (CSA3) could be used as an alternative to considerably reduce the time of analysis without compromise muscle size-strength relationship.
Revista Brasileira de Ciência e Movimento, May 6, 2009
Resumo O objetivo desse trabalho foi levantar e discutir as controvérsias na literatura, esclarec... more Resumo O objetivo desse trabalho foi levantar e discutir as controvérsias na literatura, esclarecendo o motivo de não se poder relacionar a flexibilidade como um fator de risco para lesões. Métodos: O estudo foi uma revisão bibliográfica, analisando estudos clínicos ...
Archivos de medicina del deporte: revista de la Federación Española de Medicina del Deporte y de la Confederación Iberoamericana de Medicina del Deporte, 2020
ABSTRACT Background: Previous studies on soccer small-sided games (SSGs) chose between with and w... more ABSTRACT Background: Previous studies on soccer small-sided games (SSGs) chose between with and without offside rule conditions without evidence-based criteria. The current study aimed to compare the positional dynamics of 3v3 SSGs with and without the offside rule. Methods: Twenty-four Brazilian U-17 national-level soccer players were recruited. They were split into eight teams and played SSGs with and without the offside rule . Positional data were gathered by a Global Positioning System, and teams’ length, width, the length per width ratio (LPWratio), stretch index and players’ spatial exploration index were calculated. Data were compared between the experimental conditions by a paired t-test. Results: Results showed that SSGs with the offside rule presented lower values of length (~16.63%, large effect), the LPWratio (~19.74%, large effect), and players’ spatial exploration (~4.13%, small-to-moderate effect). Conclusion: We conclude that the offside rule impacts players’ positional behavior in SSGs, inducing a less exploratory behavior mainly in the width axis. For this reason, we recommend caution when interpreting previous results on SSG when the offside rule was not applied since adopting this rule might elicit different responses to the players . Coaches can manipulate this rule aiming to achieve specific tactical goals for the training session.
Muscle volume (MV) and anatomical cross-sectional area (CSA) are used as measures of muscle-size,... more Muscle volume (MV) and anatomical cross-sectional area (CSA) are used as measures of muscle-size, but determining these from magnetic resonance imaging (MRI) is a very time-consuming process. Additionally, it is unclear if the use of different muscle size assessments (all vs. reduced number of slices images) would impact the muscle size-strength relationship. Thus, this study aimed to investigate if muscle size calculation by using a reduced or all slices images from pectoralis major (PM) would maintain a similar muscle size-strength relationship with bilateral maximal dynamic and isometric contractions on a bench press exercise. Twenty-four healthy males underwent an MRI examination to measure PM muscle size, and maximal isometric and dynamic contractions (by one repetition maximum, 1RM) were performed. Correlations between maximal isometric voluntary force (MVF) and dynamic strength (1RM) with muscle size variables [three images from the largest part of PM (CSA3MAX), three images accounting for the shape -first image, middle image, final image- of the PM (CSA3), and MV] were performed. The correlation between 1RM with MV, CSA3, and CSA3MAX were 0.84, 0.832, and 0.727 (p < 0.001), respectively. The correlation between MVF with MV, CSA3, and CSA3MAX were 0.738, 0.733, and 0.604 (p < 0.001), respectively. Overall, PM MV and CSA3 exhibit a stronger and similar muscle size-strength relationship during maximal dynamic and isometric tests than CSA3MAX. Therefore, a reduced number of slices (CSA3) could be used as an alternative to considerably reduce the time of analysis without compromise muscle size-strength relationship.
Revista Brasileira de Ciência e Movimento, May 6, 2009
Resumo O objetivo desse trabalho foi levantar e discutir as controvérsias na literatura, esclarec... more Resumo O objetivo desse trabalho foi levantar e discutir as controvérsias na literatura, esclarecendo o motivo de não se poder relacionar a flexibilidade como um fator de risco para lesões. Métodos: O estudo foi uma revisão bibliográfica, analisando estudos clínicos ...
Uploads
Papers by Mauro Chagas