Time structure and EMG parameters during the sprint start depending on the sprinters' physical preparation

Objective. - The primary of the study was to identify relations between motor preparation and speed parameters in the group of experts-sprinters and in the group of novices-students. Interdependence was examined between speed and force factors and indicators of EMG movement structure: bioelectric muscle voltage and muscle activation timing. Material and methods. - The participants were of 20 1st and 2nd sport class sprinters and a group of 35 students-novices. Force and jumping ability preparation tests were used in the study (standing long jump, standing triple jump and both feet jump with the use of Kistler platform), speed preparation test (30m run from start block) and EMG signal recording. Results. - In the post-start phase, the sprinter's group was triggered lower limb muscle groups appropriate for the given sprint start phase (front muscle group: VL: vastus lateralis; RF: rectus femoris; GAS. MED.: gastrocnemius medialis and the back muscle group: STN: semitendinosus and BF: biceps femoris), while the student group demonstrated an advantage in activation of muscles of the upper limbs: BB: biceps brachii and TB: triceps brachii in the same phase. Conclusions. - On the basis of the present research, a low start motion pattern was created, which enables proper selection of appropriate sprinter technique exercises. It has also been demonstrated that the effectiveness of sprinters' start technique is affected by factors from the area of coordination conditions. But in the group of students the sprint start depends mainly on physical preparation (force-speed predispositions). (C) 2018 Elsevier Masson SAS. All rights reserved.