Background: Much of the existing research concerning the use of video feedback (VFB) to enhance motor learning has been undertaken under strictly controlled experimental conditions. Few studies have sought to explore the impact of VFB on the skill learning experience of the students in a structured, school-based physical education (PE) setting. Most of those studies have only used qualitative approaches to implicate the potential value of VFB to enhance skill acquisition, students' engagement or selfassessment ability. Using a quantitative approach, the aim of this study was to investigate effects of using VFB on motor skill acquisition, selfassessment ability and motivation in a school-based learning environment (structured PE programme) with novice children learning a gymnastic skill. Method: Two French classes of beginners took part in a typical five-week learning programme in gymnastics. During each of the five, weekly lessons participants carried out the same warm-up routine and exercises. The experimental group (10 girls-8 boys, 12.4 ± 0.5 years) received VFB intermittently when learning a front handstand to flat back landing. VFB was given after every five attempts, combined with self-assessment and verbal instructions from the teacher. The control group (12 girls-13 boys, 12.6 ± 0.4 years) received exactly the same training but was not given VFB. In order to assess progress in motor skills, the arm-trunk angle (handshoulder-hip) was measured in the sagittal plane just as the hips formed a vertical line with the shoulders. Motivation was assessed using the Situational Motivation Scale questionnaire (Guay, F., R. J. Vallerand, and C. Blanchard. 2000. "On the Assessment of Situational Intrinsic and Extrinsic Motivation: The Situational Motivation Scale (SIMS)." Motivation and Emotion 24 (3): 175-213), and self-assessment ability was measured by self-perception task scores. Results: Statistical analysis of arm-trunk angle values showed significant differences only for the VFB group between the fifth lesson and all other lessons. Between lessons 4 and 5, the arm-trunk angle value increased significantly from 146.6 ± 16.9 degrees to 161.2 ± 14.2 degrees (p < .001; ES = 0.94). Self-assessment scores improved significantly for the VFB group between lesson 1 and lesson 2 (p < 0.01, ES = 1.79) and between lesson 4 to lesson 5 (p < .01, ES = 0.94). Amotivation decreased significantly for the VFB group between lesson 1 and lesson 5 (3.06 ± 1.42 vs. 2.12 ± 0.62, p < .001, ES = −0.89).

Various optimization algorithms have been used to achieve optimal control of sports movements. Nevertheless, no local or global optimization algorithm could be the most effective for solving all optimal control problems. This study aims at comparing local and global optimal solutions in a multistart gradient-based optimization by considering actual repetitive performances of a group of athletes performing a transition move on the uneven bars. Twenty-four trials by eight national-level female gymnasts were recorded using a motion capture system, and then multistart sequential quadratic programming optimizations were performed to obtain global optimal, local optimal and suboptimal solutions. The multistart approach combined with a gradient-based algorithm did not often find the local solution to be the best and proposed several other solutions including global optimal and suboptimal techniques. The qualitative change between actual and optimal techniques provided three directions for training: to increase hip flexion-abduction, to transfer leg and arm angular momentum to the trunk and to straighten hand path to the bar.

Le but de l'étude est de tester l'effet d'un dispositif de feedbacks augmentés basé sur le vidéofeedback à l'ensemble d'une classe sur l'apprentissage d'une habileté couramment visée en EPS, l'appui tendu renversé. A partir d'une revue de littérature centrée sur les fonctions et les conditions d'émission du feedback afin d'optimiser les apprentissages moteurs, un dispositif est pensé et mis en place durant les quatre premières semaines d'un cycle de gymnastique avec une classe de sixième (19 élèves). Ce dispositif consiste à proposer à tous les élèves, lors d'un essai sur cinq, une série de feedbacks : un feedback interrogatif, un feedback vidéo et un feedback prescriptif. Les résultats montrent une amélioration significative de la motricité ainsi qu'une augmentation de la motivation intrinsèque et une diminution de l'amotivation lors de la réalisation de l'exercice lié au dispositif. Si certaines limites sont prises en compte dans l'interprétation des résultats, les auteurs encouragent l'analyse de ce type d'innovations pédagogiques par une approche technologique afin d'améliorer les stratégies d'enseignement. Mots-clés : vidéofeedback, appui tendu renversé, apprentissages moteurs, motivation, approche technologique.

IntroductionTeaching acrobatic skills with a minimal amount of repetition is a major challenge for coaches. Biomechanical, statistical or computer simulation tools can help them identify the most determinant factors of performance. Release parameters, change in moment of inertia and segmental momentum transfers were identified in the prediction of acrobatics success. The purpose of the present study was to evaluate the relative contribution of these parameters in performance throughout expertise or optimisation based improvements. The counter movement forward in flight (CMFIF) was chosen for its intrinsic dichotomy between the accessibility of its attempt and complexity of its mastery.MethodsThree repetitions of the CMFIF performed by eight novice and eight advanced female gymnasts were recorded using a motion capture system. Optimal aerial techniques that maximise rotation potential at regrasp were also computed. A 14-segment-multibody-model defined through the Rigid Body Dynamics Library was used to compute recorded and optimal kinematics, and biomechanical parameters. A stepwise multiple linear regression was used to determine the relative contribution of these parameters in novice recorded, novice optimised, advanced recorded and advanced optimised trials. Finally, fixed effects of expertise and optimisation were tested through a mixed-effects analysis.Results and discussionVariation in release state only contributed to performances in novice recorded trials. Moment of inertia contribution to performance increased from novice recorded, to novice optimised, advanced recorded, and advanced optimised trials. Contribution to performance of momentum transfer to the trunk during the flight prevailed in all recorded trials. Although optimisation decreased transfer contribution, momentum transfer to the arms appeared.ConclusionFindings suggest that novices should be coached on both contact and aerial technique. Inversely, mainly improved aerial technique helped advanced gymnasts increase their performance. For both, reduction of the moment of inertia should be focused on. The method proposed in this article could be generalized to any aerial skill learning investigation.