Kinematics, kinetics and muscular activity of 15-s all-out handcycling exercise in able-bodied participants

The aim of this study was to examine the biomechanics of handcycling during the course of a 15-s all-out sprint test in able-bodied participants. Twelve able-bodied competitive triathletes performed a 15-s all-out sprint test in a recumbent racing handcycle that was attached to an ergometer. During the sprint test, tangential crank kinetics, 3D joint kinematics and muscular activity of ten muscles of the upper extremity and trunk [M. trapezius (TD); M. pectoralis major (PM); M. deltoideus, Pars clavicularis (DA); M. deltoideus, Pars spinalis (DP); M. biceps brachii (BB); M. triceps brachii (TB); forearm flexors (FC); forearm extensors (EC); M. latissimus dorsi (LD) and M. rectus abdominis (RA)] were examined using surface electromyography (sEMG) and motion capturing. Muscular activity was assessed by muscular effort (iEMG), onset, offset and range of activation (RoA). Variables were examined with respect to crank position and used to determine the maximum, minimum and range within crank cycle. Parameters were compared between revolution one (R1), revolution two (R2), the average of revolution three to thirteen (R3) and the average of the remaining revolutions (R4). Whereas the crank torque demonstrated a decrease during the course of the sprint test, cadence rather increased. Shoulder abduction and internal-rotation increased, whereas maximal retroversion was decreased during the course of the sprint. DA, PM, DA, BB and RA demonstrated an increase in iEMG. The onset of muscular activation occurred earlier in crank cycle for PM, DA, BB, TB and RA. RoA increased for PM, DP, BB, TB and LD. The study demonstrates that kinematics, kinetics and muscular activation of all-out handcycling exercise are altered during the course of a 15-s sprint test. The most notable alterations occurred in shoulder kinematics and the activation of DA that is spanned across. There is need to pay particular attention on the condition of the shoulder region.