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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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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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Alexandra Laurent, Annie Rouard, Vishveshwar R. Mantha, Daniel A. Marinho, Antonio J. Silva, and Abel I. Rouboa

The distribution of pressure coefficient formed when the fluid contacts with the kayak oar blade is not been studied extensively. The CFD technique was employed to calculate pressure coefficient distribution on the front and rear faces of oar blade resulting from the numerical resolution equations of the flow around the oar blade in the steady flow conditions (4 m/s) for three angular orientations of the oar (45°, 90°, 135°) with main flow. A three-dimensional (3D) geometric model of oar blade was modeled and the kappa-epsilon turbulence model was applied to compute the flow around the oar. The main results reported that, under steady state flow conditions, the drag coefficient (Cd = 2.01 for 4 m/s) at 90° orientation has the similar evolution for the different oar blade orientation to the direction of the flow. This is valid when the orientation of the blade is perpendicular to the direction of the flow. Results indicated that the angle of oar strongly influenced the Cd with maximum values for 90° angle of the oar. Moreover, the distribution of the pressure is different for the internal and external edges depending upon oar angle. Finally, the difference of negative pressure coefficient Cp in the rear side and the positive Cp in the front side, contributes toward propulsive force. The results indicate that CFD can be considered an interesting new approach for pressure coefficient calculation on kayak oar blade. The CFD approach could be a useful tool to evaluate the effects of different blade designs on the oar forces and consequently on the boat propulsion contributing toward the design improvement in future oar models. The dependence of variation of pressure coefficient on the angular position of oar with respect to flow direction gives valuable dynamic information, which can be used during training for kayak competition.

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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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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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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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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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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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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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Henrique P. Neiva, Mario C. Marques, Ricardo J. Fernandes, João L. Viana, Tiago M. Barbosa, and Daniel A. Marinho

Purpose:

To investigate the effect of warm-up on 100-m swimming performance.

Methods:

Twenty competitive swimmers (with a training frequency of 8.0 ± 1.0 sessions/wk) performed 2 maximal 100-m freestyle trials on separate days, with and without prior warm-up, in a counterbalanced and randomized design. The warm-up distance totaled 1000 m and replicated the swimmers’ usual precompetition warm-up strategy. Performance (time), physiological (capillary blood lactate concentrations), psychophysiological (perceived exertion), and biomechanical variables (distance per stroke, stroke frequency, and stroke index) were assessed on both trials.

Results:

Performance in the 100-m was fastest in the warm-up condition (67.15 ± 5.60 vs 68.10 ± 5.14 s; P = .01), although 3 swimmers swam faster without warm-up. Critical to this was the 1st 50-m lap (32.10 ± 2.59 vs 32.78 ± 2.33 s; P < .01), where the swimmers presented higher distance per stroke (2.06 ± 0.19 vs. 1.98 ± 0.16 m; P = .04) and swimming efficiency compared with the no-warm-up condition (stroke index 3.46 ± 0.53 vs 3.14 ± 0.44 m2 · c−1 · s−1; P < .01). Notwithstanding this better stroke-kinematic pattern, blood lactate concentrations and perceived exertion were similar between trials.

Conclusions:

These results suggest that swimmers’ usual warm-up routines lead to faster 100-m freestyle swimming performance, a factor that appears to be related to better swimming efficiency in the 1st lap of the race. This study highlights the importance of performing swimming drills (for higher distance per stroke) before a maximal 100-m freestyle effort in similar groups of swimmers.