Purpose: Hamstring muscle architecture may be associated with sprint performance and the risk of sustaining a muscle injury, both of which increase during puberty. In this study, we investigated the m. biceps femoris long head (BFlh) cross-sectional area (ACSA), fascicle length (FL) and pennation angle (PA), and sprint performance as well as their relationship in under 13 to 15 youth soccer players. Methods: We measured 85 players in under-13 (n = 29, age = 12.5 [0.1] y, height = 155.3 [6.2] cm, weight = 43.9 [7.6] kg), under-14 (n = 25, age = 13.5 [0.3] y, height = 160.6 [7.7] cm, weight = 47.0 [6.8] kg), and under-15 (n = 31, age = 14.4 [0.3] y, height = 170.0 [7.7] cm, weight = 58.1 [8.8] kg) teams. We used ultrasound to measure BFlh ACSA, FL and PA, and sprint tests to assess 10- and 30-m sprint time, maximal velocity (v max), and maximal acceleration (α max). We calculated Pearson r to assess the relationship between sprint ability and architectural parameters. Results: All muscle architectural parameters increased from the under-13 to the under-15 age group (BFlh ACSA = 37%, BFlh FL = 11%, BFlh PA = 8%). All sprint performance parameters improved from the under-13 to under-15 age categories (30-m time = 7%, 10-m time = 4%, v max = 9%, α max = 7%). The BFlh ACSA was correlated with 30-m sprint time (r = −.61 (95% compatibility interval [CI] [−.73, −.45]) and v max (r = .61, 95% CI [.45, .72]). A combination of BFlh ACSA and age best predicted 30-m time (R² = .47 [.33, .62]) and 10-m time (R² = .23 [.08, .38]). Conclusions: Muscle architectural as well as sprint performance parameters increase from the under-13 to under-15 age groups. Even though we found correlations for all assessed architectural parameters, BFlh ACSA was best related to the assessed sprint parameters.
Paul Ritsche, Thomas Bernhard, Ralf Roth, Eric Lichtenstein, Martin Keller, Sabrina Zingg, Martino V. Franchi, and Oliver Faude
Iván Peña-González, José M. Sarabia, Alba Roldan, Agustín Manresa-Rocamora, and Manuel Moya-Ramón
In regular football, the players’ selection process involves an objective assessment based on their anthropometric and physical performance. However, available literature focused on players’ selection process in cerebral palsy (CP) football is scarce. Purpose: To describe the anthropometrical and physical performance profiles of the International Spanish CP footballers and to compare them with the remaining CP football players from the national competition. Method: A total of 75 CP football players from the Spanish CP Football National Competition (classified into the 3 existing classes: football class [FT] 1 = 38; FT2 = 29; FT3 = 8) participated in the study. Participants were divided into 2 groups: selected players (n = 15) and nonselected players (n = 60) for the national team. Anthropometrical data and physical performance (countermovement jump, 20-m sprint, modified agility T-test [MAT], and dribbling test) were collected. Results: There were significant differences in the 20-m sprint, MAT, and dribbling for the total sample and in MAT and dribbling for FT2 and FT3 classes between selected players and nonselected players (P < .05), but there were no differences for FT1. The MAT and dribbling showed a positive correlation and a high percentage of player selection prediction. Conclusion: Change-of-direction ability (ie, MAT) and dribbling skills are important when performing the selection process, as they allow the evaluation of important aspects of the game, but they may also provide the technical staff with an idea of the functionality and the physical performance of the players in each sport class.
Satoshi Aikawa and Hideaki Takai
Athletes believe imagery is essential for high-quality performance. It is essential to identify what type of imagery significantly contributes to performance. The purpose of this study was to examine the relationship between imagery ability and gymnastics performance, as well as self-efficacy and thoughts during competitions that are related to performance. Fifty-two gymnasts were recruited for this study. Participants were measured for imagery ability, self-efficacy, thoughts during competitions, and performance. Results indicated that skill imagery significantly predicts worry and disengagement in a negative manner, and mastery imagery is positively related to self-efficacy. Moreover, goal imagery has a significant positive relationship to self-efficacy, disengagement, confidence, and performance. In conclusion, the ability to easily image an ideal performance, such as the success of one’s performance or the image of a perfect performance, might increase confidence in the competition and lead to the success of the performance.
José María González-Ravé, Francisco Hermosilla, Fernando González-Mohíno, Arturo Casado, and David B. Pyne
A well-planned periodized approach allows swimmers to achieve peak performance at the major national and international competitions. Purpose: To identify the main characteristics of endurance training for highly trained swimmers described by the training intensity distribution (TID), volume, and periodization models. Methods: The electronic databases Scopus, PubMed, and Web of Science were searched using a comprehensive list of relevant terms. Studies that investigated the effect of the periodization of training in swimming, with the training load (volume, TID) and periodization reported, were included in the systematic review. Results: A total of 3487 studies were identified, and after removal of duplicates and elimination of papers based on title and abstract screening, 17 articles remained. A further 8 articles were excluded after full text review, leaving a final total of 9 studies in the systematic review. The evidence levels were 1b for intervention studies (n = 3) and 2b for (observational) retrospective studies (n = 6). The sprint swimmers typically followed a polarized and threshold TID, the middle-distance swimmers followed a threshold and pyramidal TID, and the long-distance swimmers primarily followed a pyramidal TID. The periodization model identified in the majority of studies selected is characterized by wave-like cycles in units like mesocycles to promote physiological adaptations and skill acquisition. Conclusions: Highly trained swimmers follow a training volume and TID based on their primary event. There is a need for further experimental studies on the effects of block and reverse periodization models on swimming performance. Although observational studies of training have limited evidence, it is unclear whether a different training/periodization approach would yield better results.
S. Sofie Lövdal, Ruud J.R. Den Hartigh, and George Azzopardi
Purpose: Staying injury free is a major factor for success in sports. Although injuries are difficult to forecast, novel technologies and data-science applications could provide important insights. Our purpose was to use machine learning for the prediction of injuries in runners, based on detailed training logs. Methods: Prediction of injuries was evaluated on a new data set of 74 high-level middle- and long-distance runners, over a period of 7 years. Two analytic approaches were applied. First, the training load from the previous 7 days was expressed as a time series, with each day’s training being described by 10 features. These features were a combination of objective data from a global positioning system watch (eg, duration, distance), together with subjective data about the exertion and success of the training. Second, a training week was summarized by 22 aggregate features, and a time window of 3 weeks before the injury was considered. Results: A predictive system based on bagged XGBoost machine-learning models resulted in receiver operating characteristic curves with average areas under the curves of 0.724 and 0.678 for the day and week approaches, respectively. The results of the day approach especially reflect a reasonably high probability that our system makes correct injury predictions. Conclusions: Our machine-learning-based approach predicts a sizable portion of the injuries, in particular when the model is based on training-load data in the days preceding an injury. Overall, these results demonstrate the possible merits of using machine learning to predict injuries and tailor training programs for athletes.
Stephen S. Cheung
Veronique Richard, Justin Mason, Stacey Alvarez-Alvarado, Inbal Perry, Benoit Lussier, and Gershon Tenenbaum
The aim of the present study was to compare the effectiveness of a learned preperformance routine (PPR) with an intuitively developed one before a simulation race on advanced swimmers’ speed and motor efficiency, as well as self-efficacy and emotional regulation. In total, 46 National Collegiate Athletic Association Division I swimmers were stratified to either the control (intuitively developed PPR) or the PPR condition, which included four instructional sessions aimed at developing a PPR. A simulated competitive race was organized before and after the intervention. For each simulation, speed and motor efficiency were measured during the race, and self-efficacy and emotions, after the completion of the race. Nonsignificant effects were revealed for speed, motor efficiency, and self-efficacy following the intervention. However, performing a learned PPR prior to racing significantly influenced the swimmers’ emotional state. These results provide some support for the effect of a PPR on emotional regulation prior to a swimming race.