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Portuguese Students’ Perceptions About the Motivational Climate in Physical Education

Paulo Pereira, Fernando Santos, and Daniel A. Marinho

Purpose: To validate the English version of the L’Echelle de Perception du Climat Motivational within a Portuguese context and analyze students’ perceptions of the motivational climate in physical education and its relationship to demographic variables, participation in extracurricular sports, and students’ grades. Methods: A total of 476 Portuguese students participated in the study and completed the L’Echelle de Perception du Climat Motivational (249 men = 52.3%; 227 women = 47.7%). Statistical analysis was used to evaluate the importance of motivational climate in physical education classes. Results: Our results suggest that the Portuguese version of the L’Echelle de Perception du Climat Motivational is valid and reliable. Furthermore, motivational climate is a predictor of both extracurricular sports participation and grades. Discussion and Conclusion: The finding that motivational climate is a predictor for extracurricular sports participation and grades supports the relevance of the climate fostered by physical education teachers and its influence on learning. This study discusses implications for research and practice.

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Empowering Primary School Students, Potential Benefits of Resistance Training Movement Activities in Physical Education: Narrative Review

Andrew Sortwell, Daniel A. Marinho, Jorge Knijnik, and Ricardo Ferraz

Physical education (PE) plays a central role in children’s and young people’s holistic development, enabling cognitive, psychomotor, and affective development while boosting healthy lifestyles and socialization. Children equipped with developed motor abilities, such as muscular strength and power, will be better prepared to learn motor performance skills and sustain the demands of learning and playing games and sports. A scientific literature search was conducted in January 2021 to identify all relevant controlled studies from January 2000 to 2021 on PE interventions and strategies based on resistance training to achieve PE outcomes. The review showed that exposure to resistance exercises in PE lessons might be beneficial for primary school students’ general physical fitness, motor performance skills proficiency, and learning diversified sport skills. Interventions that include muscular strength and power development can support adequate muscular fitness and motor performance skill proficiency to achieve primary school PE outcomes.

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Numerical Simulation of Two-Phase Flow Around Flatwater Competition Kayak Design-Evolution Models

Vishveshwar R. Mantha, António J. Silva, Daniel A. Marinho, and Abel I. Rouboa

The aim of the current study was to analyze the hydrodynamics of three kayaks: 97-kg-class, single-rower, flatwater sports competition, full-scale design evolution models (Nelo K1 Vanquish LI, LII, and LIII) of M.A.R. Kayaks Lda., Portugal, which are among the fastest frontline kayaks. The effect of kayak design transformation on kayak hydrodynamics performance was studied by the application of computational fluid dynamics (CFD). The steady-state CFD simulations where performed by application of the k-omega turbulent model and the volume-of-fluid method to obtain two-phase flow around the kayaks. The numerical result of viscous, pressure drag, and coefficients along with wave drag at individual average race velocities was obtained. At an average velocity of 4.5 m/s, the reduction in drag was 29.4% for the design change from LI to LII and 15.4% for the change from LII to LIII, thus demonstrating and reaffirming a progressive evolution in design. In addition, the knowledge of drag hydrodynamics presented in the current study facilitates the estimation of the paddling effort required from the athlete during progression at different race velocities. This study finds an application during selection and training, where a coach can select the kayak with better hydrodynamics.

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Cluster Stability as a New Method to Assess Changes in Performance and its Determinant Factors Over a Season in Young Swimmers

Jorge E. Morais, António J. Silva, Daniel A. Marinho, Ludovic Seifert, and Tiago M. Barbosa

Purpose:

To apply a new method to identify, classify, and follow up young swimmers based on their performance and its determinant factors over a season and analyze the swimmers’ stability over a competitive season with that method.

Methods:

Fifteen boys and 18 girls (11.8 ± 0.7 y) part of a national talent-identification scheme were evaluated at 3 different moments of a competitive season. Performance (ie, official 100-m freestyle race time), arm span, chest perimeter, stroke length, swimming velocity, speed fluctuation, coefficient of active drag, propelling efficiency, and stroke index were selected as variables. Hierarchical and k-means cluster analysis were computed.

Results:

Data suggested a 3-cluster solution, splitting the swimmers according to their performance in all 3 moments. Cluster 1 was related to better performances (talented swimmers), cluster 2 to poor performances (nonproficient swimmers), and cluster 3 to average performance (proficient swimmers) in all moments. Stepwise discriminant analysis revealed that 100%, 94%, and 85% of original groups were correctly classified for the 1st, 2nd, and 3rd evaluation moments, respectively (0.11 ≤ Λ ≤ 0.80; 5.64 ≤ χ2 ≤ 63.40; 0.001 < P ≤ .68). Membership of clusters was moderately stable over the season (stability range 46.1–75% for the 2 clusters with most subjects).

Conclusion:

Cluster stability is a feasible, comprehensive, and informative method to gain insight into changes in performance and its determinant factors in young swimmers. Talented swimmers were characterized by anthropometrics and kinematic features.

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Modeling the Links Between Young Swimmers’ Performance: Energetic and Biomechanic Profiles

Tiago M. Barbosa, Mário Costa, Daniel A. Marinho, Joel Coelho, Marc Moreira, and António J. Silva

The aim was to develop a path-flow analysis model for young swimmers’ performance based on biomechanical and energetic parameters, using structural equation modeling. Thirty-eight male young swimmers served as subjects. Performance was assessed by the 200-m freestyle event. For biomechanical assessment the stroke length, the stroke frequency and the swimming velocity were analyzed. Energetics assessment included the critical velocity, the stroke index and the propulsive efficiency. The confirmatory model explained 79% of swimming performance after deleting the stroke index-performance path, which was nonsignificant (SRMR = 0.06). As a conclusion, the model is appropriate to explain performance in young swimmers.

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Young Swimmers’ Classification Based on Performance and Biomechanical Determinants: Determining Similarities Through Cluster Analysis

Jorge E. Morais, Tiago M. Barbosa, Henrique P. Neiva, Mario C. Marques, and Daniel A. Marinho

The aim of this study was to classify and identify young swimmers’ performance, and biomechanical determinant factors, and understand if both sexes can be clustered together. Thirty-eight swimmers of national level (22 boys: 15.92 ± 0.75 years and 16 girls: 14.99 ± 1.06 years) were assessed. Performance (swim speed at front crawl stroke) and a set of kinematic, efficiency, kinetic, and hydrodynamic variables were measured. Variables related to kinetics and efficiency (p < .001) were the ones that better discriminated the clusters. All three clusters included girls. Based on the interaction of these determinant factors, there are girls who can train together with boys. These findings indicate that not understanding the importance of the interplay between such determinants may lead to performance suppression in girls.

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Determinant Factors of Long-Term Performance Development in Young Swimmers

Jorge E. Morais, António J. Silva, Daniel A. Marinho, Vítor P. Lopes, and Tiago M. Barbosa

Purpose:

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.

Methods:

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.

Results:

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.

Conclusion:

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.

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The Effects of 6-Week Training Cessation on Anthropometrics, in-Water Force, Performance, and Kinematics of Young Competitive Swimmers: A Maturity Development Approach

Catarina C. Santos, Mário J. Costa, and Daniel A. Marinho

Purpose: To examine the effects of 6 weeks of training cessation on young swimmers’ anthropometrics, in-water force, performance, and kinematics according to biological maturation. Methods: Eighteen swimmers (7 girls: 12.43 [0.73] y old; 11 boys: 13.27 [0.79] y old) were assessed pretest and posttest 6 weeks apart. Body mass, stature, arm span, and hand surface area were measured as anthropometric parameters, and biological maturation was estimated (ie, peak height velocity [PHV]). The in-water force was retrieved during 2 bouts of 25-m front crawl, allowing the estimation of the symmetry index. The time to complete the 25-m was considered the performance outcome, whereas velocity, stroke rate, stroke length, stroke index, and arm stroke efficiency were used as kinematic parameters. Results: All anthropometric parameters increased during the detraining period. Although the in-water force remained unchanged, the magnitude of the effects was large for the symmetry index (P = .021; d = 0.87). For the pooled sample, neither performance nor kinematics changed after detraining, but the stroke index increased (P = .054; d = 0.27). Pre-PHV swimmers showed unchanged values in all parameters, despite natural growth. Mid-PHV swimmers showed a similar trend in addition to reductions in stroke rate (P = .040; d = 0.60) and increases in stroke length (P = .043; d = 1.00). Conclusions: In-water force, performance, and kinematics (25-m front crawl) were not impaired after 6 weeks of training cessation in a group of young swimmers. Given interindividual and intraindividual differences according to maturity status, coaches should be aware that distinct trends within the group can be found.

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Potential Role of Plyometric Training in the Development of Motor Performance Skills: A Narrative Review

Andrew Sortwell, Michael Newton, Daniel A. Marinho, Jorge Knijnik, and Rodrigo Ramirez-Campillo

Offering children chances to optimize their engagement in physical activities during their life span is one of the major aims of school physical education (PE). To this end, the maximum development of motor performance skills can help primary school children participate in various physical activities throughout their lives. The purpose of this review was to examine the effects of plyometric training activities on motor performance skills of children and the application of plyometrics within the PE setting. Relevant studies on the topics of motor performance skills, plyometrics, athlete development, and motor development in children and adolescents were examined. The paper reveals that plyometric training activities can improve motor performance skills such as running, jumping, and kicking. The literature also suggests that children’s exposure to plyometric exercises may result in an accelerated improvement in primary school PE class. This review concludes with a proposal to enhance children’s motor performance skills using plyometric exercises in primary PE classes.

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Interaction of Kinematic, Kinetic, and Energetic Predictors of Young Swimmers’ Speed

Jorge E. Morais, Tiago M. Barbosa, José A. Bragada, Rodrigo Ramirez-Campillo, and Daniel A. Marinho

Purpose: The aim of this study was to assess the interaction of kinematic, kinetic, and energetic variables as speed predictors in adolescent swimmers in the front-crawl stroke. Design: Ten boys (mean age [SD] = 16.4 [0.7] y) and 13 girls (mean age [SD] = 14.9 [0.9] y) were assessed. Methods: The swimming performance indicator was a 25-m sprint. A set of kinematic, kinetic (hydrodynamic and propulsion), and energetic variables was established as a key predictor of swimming performance. Multilevel software was used to model the maximum swimming speed. Results: The final model identified time (estimate = −0.008, P = .044), stroke frequency (estimate = 0.718, P < .001), active drag coefficient (estimate = −0.330, P = .004), lactate concentration (estimate = 0.019, P < .001), and critical speed (estimate = −0.150, P = .035) as significant predictors. Therefore, the interaction of kinematic, hydrodynamic, and energetic variables seems to be the main predictor of speed in adolescent swimmers. Conclusions: Coaches and practitioners should be aware that improvements in isolated variables may not translate into faster swimming speed. A multilevel evaluation may be required for a more effective assessment of the prediction of swimming speed based on several key variables rather than a single analysis.