Daniel Dinu

Does the Use of a Light Discus Modify the Throwing Pattern? A Study of Kinematical and Electromyographical Data of the Throwing Arm (P276)

Seven high-level discus throwers (best performance 57 ± 3 m) participated to the present study. During the same session, they performed 12 throws (6 with a 1.7 kg discus and 6 with a 2 kg discus) in a random order. The throwing distance was computed from the velocity vector (magnitude, direction, height) at ejection. Kinematical data were collected by means of 3 video-cameras and a 3-D modelling of the throwing movement was processed according to the DLT method. Surface electromyograms (sEMG) of 6 arm-and-shoulder muscles of the throwing arm [Biceps brachii ; Pectoralis major ; Deltoideus pars superior ; Trapezius pars medialis ; Deltoideus pars medialis ; Latissimus dorsi] were recorded by means of a portable device. Thereafter, sEMG was integrated (iEMG) and related to the iEMG recorded during a maximal effort against an external resistance. Computed distance with a light discus was significantly longer and was the result of a faster discus speed at ejection. This was probably the result of an enhanced increase in discus velocity during the last throwing phase (δt2da). There was no significant difference in the duration of the four preceding phases with 1.7 kg compared to 2 kg discus. The total duration of the throwing movement was not significantly different between 1.7 and 2 kg discus. The EMG patterns of the different muscles were similar with both discuses when the beginning and the end of the muscle activity were considered. There was no significant difference between discuses when iEMG was summated on the whole throwing movement and related to the iEMG previously recorded during a maximal effort. These results suggest that the lighter discus might be used for high level training without kinematical alteration of throwing.

The Effects of Repeated Sprints on the Kinematics of 3-Point Shooting in Basketball

Abstract Fatigue modifies the kinematics of various sports-related movements. Basketball induces fatigue, however, the effects of fatigue on the kinematics of shooting have never been studied. This study analysed the effects of fatigue induced by repeated sprints on the kinematics of 3-point shooting (3PS) in young, elite basketball players (U18 level). 3D joint angles were calculated at the maximum and minimum heights of the centre of mass during 3PS, using inertial measurement units (Biomech system, Xsens Technologies BV, Enschede, The Netherlands). Height, velocity and the angle of the ball at the time of release were extrapolated from the wrist joint angles. All players performed four 3PS actions in dynamic conditions before and after a fatigue protocol at 70% of their maximal exercise capacity. The fatigue protocol consisted of a shuttle test with repeated 20-m sprints interspersed with sets of 5 jumps. There was no change in the kinematics of 3PS (p > 0.05), or the ball release variables (p > 0.05) following the fatigue protocol. This suggests that elite basketball players are able to cope with physical fatigue while performing coordinated movements such as 3PS.

Analyse Cinematique et Energetique du Geste du Lancer du Marteau

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Analyse Cinematique et Energetique du Geste du Lancer du Marteau Gilles Dietrich, Daniel Dinu, G. Guérin