Race level comparison and variability analysis of 100 m freestyle sprinters competing in the 2019 European championships

This study aimed to (i) compare the race performance of the swimmers with better performances and poorer performances during all sections of a 100 m freestyle event and (ii) compare stroke kinematics variables between tiers and analyse their stability in each tier. The sample was composed of 88 swimmers that participated in the 100 m Freestyle event at the 2019 LEN European Junior Championships. Speed achieved the largest difference between tiers in section (S) S0-15 m of lap #1 (mean difference = -0.109 s, p < 0.001). During the clean swim and finish phases, the stroke length and stroke index presented significant differences (p < 0.05) between tiers in all sections of the race (stroke frequency did not). Significant variances were noted for both tiers in all variables in both laps. Swimmers in tier #1 were significantly faster than swimmers in tier #2 especially in sections related to the push-off against a solid (block or wall), and finish. A significant variance was noted by both tiers during the race with a moderate-to-high normative stability. Coaches are advised to analyse and understand the swimmers' within-lap stability, which can give deeper details about their swimmers' behaviour during the 100 m freestyle race.This work was supported by the Fundacao para a Ciencia e a Tecnologia [UIDB/DTP/04045/2020]info:eu-repo/semantics/publishedVersio

Numerical and experimental methods used to evaluate active drag in swimming: a systematic narrative review

In swimming, it is necessary to understand and identify the main factors that are important to reduce active drag and, consequently, improve the performance of swimmers. However, there is no up-to-date review in the literature clarifying this topic. Thus, a systematic narrative review was performed to update the body of knowledge on active drag in swimming through numerical and experimental methods.This work is supported by national funds (FCT -Portuguese Foundation for Science and Technology) with the reference 2020.07194.BD and the project UIDB/DTP/04045/2020info:eu-repo/semantics/publishedVersio

The influence of a specific high intensity circuit training during physical education classes in children’s physical activity and body composition markers

Physical activity plays a paramount role on children growth and schools emerged as a key setting for promoting physical activity during childhood. The aim of this study was to verify the effects of a high intensity circuit training performed during regular physical education classes at schools. One hundred and five children aged 11–14 years (71 boys and 34 girls) were evaluated. The participants were split into a control group (boys: N = 47; girls: N = 16) and an experimental group (boys: N = 24; girls: N = 18). Besides the normal physical education classes, the experimental group also performed a high intensity circuit training for eight weeks, twice a week, at the beginning of the lesson. A pre- post-test was performed. Cardiorespiratory (20 m shuttle run test ) and a set of strength variables were evaluated. Percentage of fat mass was used as a somatic indicator. The 20 m shuttle run test presented a significant time effect, but not a time X sex, time X group, and time X weight status interactions. Conversely, the strength variables presented a significant time X group interaction (significant differences between groups). Percentage of fat mass presented a significant time effect, but not a significant time X group interaction. Data showed that adding a high intensity circuit training to physical education classes would result in a significant increase in muscular fitness performance in children, but cardiorespiratory fitness may not present the same magnitude of improvement. High intensity circuit training programs (performed during regular physical education classes at schools) seem to present a positive and significant effect in physical fitness parameters as well as reducing the percentage of fat mass.This work is supported by national funds (FCT - Portuguese Foundation for Science and Technology) under the project UIDB/DTP/04045/2020info:eu-repo/semantics/publishedVersio

The influence of a specific high intensity circuit training during physical education classes in children’s physical activity and body composition markers

Physical activity plays a paramount role on children growth and schools emerged as a key setting for pro- moting physical activity during childhood. The aim of this study was to verify the effects of a high intensi- ty circuit training performed during regular physical education classes at schools. One hundred and five children aged 11–14 years (71 boys and 34 girls) were evaluated. The participants were split into a control group (boys: N = 47; girls: N = 16) and an experimental group (boys: N = 24; girls: N = 18). Besides the normal physical education classes, the experimental group also performed a high intensity circuit training for eight weeks, twice a week, at the beginning of the lesson. A pre- post-test was performed. Cardiorespiratory (20 m shuttle run test ) and a set of strength variables were evaluated. Percentage of fat mass was used as a somatic indicator. The 20 m shuttle run test presented a significant time effect, but not a time X sex, time X group, and time X weight status interactions. Conversely, the strength variables presented a significant time X group interaction (significant differences between groups). Percentage of fat mass presented a significant time effect, but not a significant time X group interaction. Data showed that adding a high intensity circuit training to physical education classes would result in a significant increase in muscular fitness performance in children, but cardiorespiratory fitness may not present the same magnitude of improvement. High in- tensity circuit training programs (performed during regular physical education classes at schools) seem to present a positive and significant effect in physical fitness parameters as well as reducing the percentage of fat mass.This work is supported by national funds (FCT - Portuguese Foundation for Science and Technology) under the project UIDB/DTP/04045/2020.info:eu-repo/semantics/publishedVersio

Determinant factors of long-term performance development in young swimmers

To develop a performance predictor model based on swimmers’ biomechanical profile, relate the partial contribution of the main predictors with the training program, and analyze the time effect, sex effect, and time × sex interaction. 91 swimmers (44 boys, 12.04 ± 0.81 y; 47 girls, 11.22 ± 0.98 y) evaluated during a 3-y period. The decimal age and anthropometric, kinematic, and efficiency features were collected 10 different times over 3 seasons (ie, longitudinal research). Hierarchical linear modeling was the procedure used to estimate the performance predictors. Performance improved between season 1 early and season 3 late for both sexes (boys 26.9% [20.88;32.96], girls 16.1% [10.34;22.54]). Decimal age (estimate [EST] –2.05, P < .001), arm span (EST –0.59, P < .001), stroke length (EST 3.82; P = .002), and propelling efficiency (EST –0.17, P = .001) were entered in the final model. Over 3 consecutive seasons young swimmers’ performance improved. Performance is a multifactorial phenomenon where anthropometrics, kinematics, and efficiency were the main determinants. The change of these factors over time was coupled with the training plans of this talent identification and development program.info:eu-repo/semantics/publishedVersio

Race analysis of the men’s 50 m events at the 2021 LEN European Championships

The aim of this study was to: (i) characterise the stroke kinematics’ stability of the male swimmers competing in the four 50 m events at the 2021 European Championships, and; (ii) understand the speed–time relationship in the four race events. All male swimmers who participated in the 50 m events (backstroke: 78 swimmers; breaststroke: 79 swimmers; butterfly: 89 swimmers; freestyle: 95 swimmers) were evaluated. In each swimming stroke swimmers were split in two groups (better and poorer performances). Significant variances (p < 0.05) were observed in both groups in all variables and for all swimming strokes. Swimming speed was the variable with the highest variance in both groups and strokes. Overall, better swimmers presented a low to high normative stability, and poorer swimmers a moderate-to-high. Speed–time curve fitting for all swimming strokes and groups suggested a cubic relationship. It can be considered that elite male swimmers racing 50 m sprint events at major competitions present an all-out trend. The present data provide coaches with substantial information about the main trend in the 50 m sprint events, specifically in each section of the race.This work is supported by national funds (FCT - Portuguese Foundation for Science and Technology) under the project UIDB/DTP/04045/2020info:eu-repo/semantics/publishedVersio

How does 11-week detraining affect 11-12 years old swimmers’ biomechanical determinants and its relationship with 100 m freestyle performance?

The aim of this study was to analyse the detraining process that occurs during a season break, and its influence on the performance, anthropometrics, and biomechanics of young swimmers. The sample included 54 young swimmers (22 boys: 12.79 +/- 0.71 years; 32 girls: 11.78 +/- 0.85 years). Performance for the 100 m freestyle and anthropometric and biomechanical variables were evaluated as main determinants. Performance impaired significantly for boys (2.17%) and girls (1.91%). All anthropometric variables increased between moments of assessment for boys and girls. Overall, the boys enhanced all biomechanical variables during the detraining period, and girls showed mixed results. For both sexes, the stroke index was the variable with the highest increase (boys: Delta = 16.16%; d = 0.89; p = 0.001; girls: Delta = 19.51%; d = 1.06; p = 0.002). Hierarchical linear modelling showed that the height retained the amount of impairment in the performance. One unit of increase in the height (cm) led to less 0.41 s impairment in the performance. Present data indicated that during an 11-weeks detraining period, young swimmers impaired their performance, but the determinant factors showed an impaired relationship. This increase in the determinant factors is mainly related to the increase in the swimmers' anthropometrics. Moreover, the increase in height was responsible for retaining the performance impairment.This project was supported by National Funds through FCT -Portuguese Foundation for Science and Technology (UID/DTP/04045/2019), and the European Fund for regional development (FEDER) allocated by the European Union through the COMPETE 2020 Programme (POCI01-0145-FEDER-006969).info:eu-repo/semantics/publishedVersio

Comparison of swimming velocity between age-group swimmers through discrete variables and continuous variables by Statistical Parametric Mapping

The aim of this study was to compare the swimming velocity in frontcrawl between age-group swimmers using discrete variables against Statistical Parametric Mapping (SPM). The sample consisted of 30 young male swimmers divided into three groups (each with 10 swimmers) based on their age (group #1: 13.60 ± 0.84 years; group #2: 15.40 ± 0.32 years; group 3: 16.39 ± 0.69 years). Swimmers performed three maximal trials in front-crawl. The best performance was used for analysis. Comparison of swimming velocity between groups was analysed using discrete variables and as a continuous variable (SPM). As a discrete variable, the mean swimming velocity showed a significant difference between groups (p < 0.05). Moreover, when analysed by SPM, swimming velocity showed a significant difference (p = 0.021) between the ~ 44% and ~ 51% of the stroke cycle (transition of the propulsion phases between sides). Post-hoc comparison revealed a significant difference between group #1 and group #3 only in SPM analysis. Researchers, coaches, and practitioners should know that both measurement approaches can be used simultaneously. However, SPM offers more sensitive and accurate results about the swimmers’ stroke cycle.This work is supported by national funds (FCT – Portuguese Foundation for Science and Technology) under the project [UIDB/DTP/04045/2020]info:eu-repo/semantics/publishedVersio

Smartpaddle® as a new tool for monitoring swimmers’ kinematic and kinetic variables in real time

Smart technology, such as wearables, applied to sports analysis is essential for performance enhancement. New technological equipment can promote the interaction between researchers, coaches, and athletes, facilitating information exchange in real time. Objective: The aim of this study was to present new wearable equipment (SmartPaddle®) to measure kinematic and kinetic variables in swimming and understand the agreement of the propulsive force variable with a pressure sensor system. Methods: Four male university swimmers (18.75±0.50 years old, 71.55±6.80 kg of body mass, and 175.00±5.94 cm of height) were analyzed. The SmartPaddle® and a pressure sensor system were used to collect the kinetic data (propulsive force). The comparison between the propulsive force methods was based on t-test paired samples, simple linear regression, and Bland-Altman plots. Results: SmartPaddle® is a system that consists of (i) a wearable device, (ii) the Trainesense Session Manager mobile application for recording, and; (iii) the Analysis Center for analysis and data storage. It records a set of kinematic and kinetic parameters useful for coaches daily. The comparison between the different methods revealed non-significant differences and a very-high relationship. Conclusion: SmartPaddle® is a feasible wearable device that swimmersswimmers can use can use to provide immediate data about their kinematic and kinetic profile. Coaches can easily monitor these parameters and give immediate suggestions to their swimmers on a daily basis.This work is supported by national funds (FCT - Portuguese Foundation for Science and Technology) under the project UIDB/DTP/04045/2020info:eu-repo/semantics/publishedVersio