Ability of Lifeguards to Detect Submerged Manikins in Public Swimming Pool Environments

To prevent drownings in public swimming pools (PSP), French legislation requires constant surveillance by state-certified lifeguards. While previous research showed that surveillance was not always effective, this article focuses on efficiency of surveillance when it is effective. We evaluated the ability of 4 volunteer professional lifeguards to detect a submerged manikin under controlled conditions. One hundred and eight (108) tests were carried out in 2 PSP. Four variables were controlled (i.e., distance, depth, surveillance station, attendance). Our results showed that rapid drowning detection was not exclusively linked to the individual detection capabilities of a lifeguard, but rather it emerged from a tight coupling between the lifeguard’s perception and his/her working environment. The tests performed in this study are useful to prevent drownings and therefore should be reproduced in other public swimming pools (i) to identify problematic situations and (ii) to train lifeguards’ surveillance capabilities

Effects of paddles and fins on front crawl kinematics, arm stroke efficiency, coordination, and estimated energy cost

Paddles and fins are used in swimmers training with different objectives (e.g., increase propulsive areas of hands and feet, improve the feeling of water flow). These artificial modifications of the stroke might be viewed as external constraints of the stroke task, both will either disturb or facilitate swimming modalities, so the coaches should manipulate its use to extract benefits for performance. This study seeks to investigate the precise effects of wearing either paddles (PAD) or fins (FINS) vs. a no-equipment (NE) trial in three all-out front crawl exercises on swimmer kinematics, arm stroke efficiency (ηp), upper-limbs coordination patterns (Index of Coordination, IdC), and estimated energy cost (C). Eleven regional to national-level male swimmers participated in the study (age: 25.8 ± 5.5 years, body mass: 75.2 ± 5.5 kg, height: 177 ± 6.5 cm) and were recorded from both sides of the swimming pool to collect all variables. Repeated measures ANOVA and Bonferroni post hoc were used to compare the variables. Effects sizes were calculated. Time to cover the distance and velocity were higher in FINS swimming, with larger values of stroke length (SL) and lower kick amplitude in comparison to the other trials (PAD and NE). The use of FINS also modified the stroke phases durations by presenting significant lower propulsion time during the stroke in comparison to PAD or NE. Values of IdC were lower (IdC < −1%, so catchup pattern of coordination) for FINS in comparison to NE. In terms of ηp, using PAD or FINS demonstrate higher arm stroke efficiency than swimming without equipment. Finally, C was significantly higher in FINS swimming in comparison to NE and PAD. From the present results, it should be noted that the use of equipment such as fins deeply modify the structure of the swimming stroke (from the performance-related parameters through the kinematics of both upper and lower limbs to the stroke efficiency and coordination pattern). So, using equipment should be appropriately scaled by the coaches to the objectives of the training session in swimming, and in emergent sports such as “SwimRun”, paddles and fins must be viewed as tools to achieve higher velocities to cover a given distance

KNEE AND ANKLE MUSCLES COACTIVATIONS IN BREASTSTROKE SWIMMING KICK AND RECOVERY: EXPLORATORY APPROACH

The specificities of body position in breaststroke induce important lower limbs solicitations for the swimmers to propel themselves efficiently. Coactivations around the knee and ankle might appear during the powerful leg extension (i.e. push) and for leg replacement (i.e. recovery). The purpose of this exploratory study is to determine muscle activations and coactivations during these two phases at three different velocities. The EMG of four muscles was recorded (BF, RF, GAS and TA). The results showed important activations of the four muscles in the push, contrary to the recovery. However, no significant differences were found for the coactivations in the two phases and for the three velocities. These findings denoted the important resistances occasioned by aquatic environment, both in push and recovery phases, necessitating muscle coactivations to stabilise joints

Education and transfer of water competencies: An ecological dynamics approach

© The Author(s) 2020. To cope in various aquatic environments (i.e. swimming pools, lakes, rivers, oceans), learners require a wide repertoire of self-regulatory behaviours such as awareness of obstacles and water properties, floating and moving from point to point with different strokes, decision making, emotional control and breathing efficiently. By experiencing different learning situations in stable indoor pool environments, it is assumed that children strengthen aquatic competencies that should be transferable to functioning in open water environments, where prevalence of drowning is high. However, this fundamental assumption may be misleading. Here, we propose the application of a clear, related methodology and theoretical framework that could be useful to help physical education curriculum specialists (re)shape and (re)design appropriate aquatic learning situations to facilitate better transfer of learning. We discuss the need for more representativeness in a learning environment, proposing how the many different task and environmental constraints on aquatic actions may bound the emergence of functional, self-regulatory behaviours in learners. Ideas in ecological dynamics suggest that physical educators should design learning environments that offer a rich landscape of opportunities for action for learners. As illustration, three practice interventions are described for developing functional and transferrable skills in indoor aquatic environments. It is important that aquatic educators focus not just upon ‘learning to swim’, but particularly on relevant transferable skills and self-regulatory behaviours deemed necessary for functioning in dynamic, outdoor aquatic environments

Education and transfer of water competencies: An ecological dynamics approach

© The Author(s) 2020. To cope in various aquatic environments (i.e. swimming pools, lakes, rivers, oceans), learners require a wide repertoire of self-regulatory behaviours such as awareness of obstacles and water properties, floating and moving from point to point with different strokes, decision making, emotional control and breathing efficiently. By experiencing different learning situations in stable indoor pool environments, it is assumed that children strengthen aquatic competencies that should be transferable to functioning in open water environments, where prevalence of drowning is high. However, this fundamental assumption may be misleading. Here, we propose the application of a clear, related methodology and theoretical framework that could be useful to help physical education curriculum specialists (re)shape and (re)design appropriate aquatic learning situations to facilitate better transfer of learning. We discuss the need for more representativeness in a learning environment, proposing how the many different task and environmental constraints on aquatic actions may bound the emergence of functional, self-regulatory behaviours in learners. Ideas in ecological dynamics suggest that physical educators should design learning environments that offer a rich landscape of opportunities for action for learners. As illustration, three practice interventions are described for developing functional and transferrable skills in indoor aquatic environments. It is important that aquatic educators focus not just upon ‘learning to swim’, but particularly on relevant transferable skills and self-regulatory behaviours deemed necessary for functioning in dynamic, outdoor aquatic environments

Individual-environment interactions in swimming: The smallest unit for analysing the emergence of coordination dynamics in performance?

Displacement in competitive swimming is highly dependent on fluid characteristics, since athletes use these properties to propel themselves. It is essential for sport scientists and practitioners to clearly identify the interactions that emerge between each individual swimmer and properties of an aquatic environment. Traditionally, the two protagonists in these interactions have been studied separately. Determining the impact of each swimmer’s movements on fluid flow, and vice versa, is a major challenge. Classic biomechanical research approaches have focused on swimmers’ actions, decomposing stroke characteristics for analysis, without exploring perturbations to fluid flows. Conversely, fluid mechanics research has sought to record fluid behaviours, isolated from the constraints of competitive swimming environments (e.g. analyses in two-dimensions, fluid flows passively studied on mannequins or robot effectors). With improvements in technology, however, recent investigations have focused on the emergent circular couplings between swimmers’ movements and fluid dynamics. Here, we provide insights into concepts and tools that can explain these on-going dynamical interactions in competitive swimming within the theoretical framework of ecological dynamics

Perception et action en natation : effets de l'environnement aquatique et de la vitesse de mouvement sur la dynamique des coordinations

The aim of this thesis is to investigate the coordination dynamics of expert swimmers as a function of both task (swimming speed) and environmental (fluid flow) constraints manipulation. The intra - and inter-segmental coordination (arms vs. arms and arms vs. legs) are assessed by inertial measurement units positioned on expert swimmers swimming two separated scanning tasks in a flume and in a pool. We investigate the effect of aquatic flow by comparing the upper limb coordination when the swimmers swim at a similar speed in pool and flume, then, the upper limb coordination dynamics during a scanning procedure where speed is increased through eight steps. Finally, the arms vs. legs coordination dynamics and the right/left asymmetry were analyzed.Our findings demonstrate that flume is channeling the emergence of functional expert swimmers’ movement patterns, in particular the decrease of glide phase duration related to the moving body of water. The increase of speed reveals larger implications of the lower limbs in the propulsion. Flume swimming leads to lower coupling strength between oscillators and higher asymmetries in the flume. Our findings thus demonstrated that experts are able to adapt their coordination patterns at different levels (intra-segmental of the upper limbs / inter-limb i.e., arms vs. legs) and by transiting between different patterns according to the constraints encountered. Thus swimmers exhibit both periods of behavioral stability and periods of adaptive flexibility, showing their ability to achieve the task-goal by functional interaction with the aquatic environment.L’objectif de ce travail est de caractériser la dynamique des coordinations de nageurs experts en fonction de la manipulation de contraintes de tâche (vitesse de nage) et d’environnement (écoulement). Les coordinations intra- et inter-membre (bras vs. bras et bras vs. jambes) sont déterminées à l’aide de centrales inertielles positionnées sur des nageurs experts, réalisant deux tâches de scanning dans une piscine et un bassin à contre-courant. Nous caractérisons l’effet de l’environnement en comparant la coordination intra-bras à la même vitesse de nage dans les deux bassins, puis la dynamique de cette même coordination et de la coordination bras vs. bras lors d’une tâche impliquant huit vitesses. Finalement, la dynamique des coordinations bras vs. jambes est analysée, tout comme l’asymétrie droite/gauche.Nos résultats montrent que le flume canalise l’émergence de comportements fonctionnels, en particulier en faisant décroître la durée de la phase de glisse du fait de l’écoulement dynamique de la masse d’eau. L’augmentation de la vitesse de nage montre de plus larges implications des jambes dans la propulsion. La nage dans le flume conduit à une force de couplage plus faible entre les bras et les jambes et de plus larges asymétries droite/gauche. Les nageurs experts sont donc capables d’adapter leurs coordinations intra- et inter-segmentaires et peuvent transiter entre différents patrons en fonction des contraintes auxquelles ils font face. Ainsi, des périodes de stabilité sont couplées avec des périodes de flexibilité comportementales, exemplifiant leur habileté pour réaliser le but de la tâche en interagissant fonctionnellement avec l’environnement aquatique

Perception et action en natation : effets de l'environnement aquatique et de la vitesse de mouvement sur la dynamique des coordinations

The aim of this thesis is to investigate the coordination dynamics of expert swimmers as a function of both task (swimming speed) and environmental (fluid flow) constraints manipulation. The intra - and inter-segmental coordination (arms vs. arms and arms vs. legs) are assessed by inertial measurement units positioned on expert swimmers swimming two separated scanning tasks in a flume and in a pool. We investigate the effect of aquatic flow by comparing the upper limb coordination when the swimmers swim at a similar speed in pool and flume, then, the upper limb coordination dynamics during a scanning procedure where speed is increased through eight steps. Finally, the arms vs. legs coordination dynamics and the right/left asymmetry were analyzed.Our findings demonstrate that flume is channeling the emergence of functional expert swimmers’ movement patterns, in particular the decrease of glide phase duration related to the moving body of water. The increase of speed reveals larger implications of the lower limbs in the propulsion. Flume swimming leads to lower coupling strength between oscillators and higher asymmetries in the flume. Our findings thus demonstrated that experts are able to adapt their coordination patterns at different levels (intra-segmental of the upper limbs / inter-limb i.e., arms vs. legs) and by transiting between different patterns according to the constraints encountered. Thus swimmers exhibit both periods of behavioral stability and periods of adaptive flexibility, showing their ability to achieve the task-goal by functional interaction with the aquatic environment.L’objectif de ce travail est de caractériser la dynamique des coordinations de nageurs experts en fonction de la manipulation de contraintes de tâche (vitesse de nage) et d’environnement (écoulement). Les coordinations intra- et inter-membre (bras vs. bras et bras vs. jambes) sont déterminées à l’aide de centrales inertielles positionnées sur des nageurs experts, réalisant deux tâches de scanning dans une piscine et un bassin à contre-courant. Nous caractérisons l’effet de l’environnement en comparant la coordination intra-bras à la même vitesse de nage dans les deux bassins, puis la dynamique de cette même coordination et de la coordination bras vs. bras lors d’une tâche impliquant huit vitesses. Finalement, la dynamique des coordinations bras vs. jambes est analysée, tout comme l’asymétrie droite/gauche.Nos résultats montrent que le flume canalise l’émergence de comportements fonctionnels, en particulier en faisant décroître la durée de la phase de glisse du fait de l’écoulement dynamique de la masse d’eau. L’augmentation de la vitesse de nage montre de plus larges implications des jambes dans la propulsion. La nage dans le flume conduit à une force de couplage plus faible entre les bras et les jambes et de plus larges asymétries droite/gauche. Les nageurs experts sont donc capables d’adapter leurs coordinations intra- et inter-segmentaires et peuvent transiter entre différents patrons en fonction des contraintes auxquelles ils font face. Ainsi, des périodes de stabilité sont couplées avec des périodes de flexibilité comportementales, exemplifiant leur habileté pour réaliser le but de la tâche en interagissant fonctionnellement avec l’environnement aquatique

Perception and action in swimming : effects of aquatic environment and speed on coordination dynamics

L’objectif de ce travail est de caractériser la dynamique des coordinations de nageurs experts en fonction de la manipulation de contraintes de tâche (vitesse de nage) et d’environnement (écoulement). Les coordinations intra- et inter-membre (bras vs. bras et bras vs. jambes) sont déterminées à l’aide de centrales inertielles positionnées sur des nageurs experts, réalisant deux tâches de scanning dans une piscine et un bassin à contre-courant. Nous caractérisons l’effet de l’environnement en comparant la coordination intra-bras à la même vitesse de nage dans les deux bassins, puis la dynamique de cette même coordination et de la coordination bras vs. bras lors d’une tâche impliquant huit vitesses. Finalement, la dynamique des coordinations bras vs. jambes est analysée, tout comme l’asymétrie droite/gauche.Nos résultats montrent que le flume canalise l’émergence de comportements fonctionnels, en particulier en faisant décroître la durée de la phase de glisse du fait de l’écoulement dynamique de la masse d’eau. L’augmentation de la vitesse de nage montre de plus larges implications des jambes dans la propulsion. La nage dans le flume conduit à une force de couplage plus faible entre les bras et les jambes et de plus larges asymétries droite/gauche. Les nageurs experts sont donc capables d’adapter leurs coordinations intra- et inter-segmentaires et peuvent transiter entre différents patrons en fonction des contraintes auxquelles ils font face. Ainsi, des périodes de stabilité sont couplées avec des périodes de flexibilité comportementales, exemplifiant leur habileté pour réaliser le but de la tâche en interagissant fonctionnellement avec l’environnement aquatique.The aim of this thesis is to investigate the coordination dynamics of expert swimmers as a function of both task (swimming speed) and environmental (fluid flow) constraints manipulation. The intra - and inter-segmental coordination (arms vs. arms and arms vs. legs) are assessed by inertial measurement units positioned on expert swimmers swimming two separated scanning tasks in a flume and in a pool. We investigate the effect of aquatic flow by comparing the upper limb coordination when the swimmers swim at a similar speed in pool and flume, then, the upper limb coordination dynamics during a scanning procedure where speed is increased through eight steps. Finally, the arms vs. legs coordination dynamics and the right/left asymmetry were analyzed.Our findings demonstrate that flume is channeling the emergence of functional expert swimmers’ movement patterns, in particular the decrease of glide phase duration related to the moving body of water. The increase of speed reveals larger implications of the lower limbs in the propulsion. Flume swimming leads to lower coupling strength between oscillators and higher asymmetries in the flume. Our findings thus demonstrated that experts are able to adapt their coordination patterns at different levels (intra-segmental of the upper limbs / inter-limb i.e., arms vs. legs) and by transiting between different patterns according to the constraints encountered. Thus swimmers exhibit both periods of behavioral stability and periods of adaptive flexibility, showing their ability to achieve the task-goal by functional interaction with the aquatic environment

Perception et action en natation : effets de l’environnement aquatique et de la vitesse de mouvement sur la dynamique des coordinations

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