Influence of different seating and crank positions on kinematics and muscular activity in elite handcycling - a case study

In this thesis the effects of changes in the seating position of an elite handbiking athlete on his upper body kinematics and muscular activity were examined to evaluate whether a change of his present seating position might be biomechanically beneficial. For a total of 22 different settings (different crank heights, backrest positions, crank lengths and power outputs) joint angles of the elbow and wrist, movement of shoulders and sternum and surface electromyography data of seven muscles (bilaterally) were collected and analysed. It was found out that the relative distance between shoulder and crank lead to minor changes in kinematics, and that different power-outputs change the kinematics of the wrist-joint. The amplitude of muscular activity increased with increased workloads and activity timing changes with different positions. However, integrated electromyography shows that metabolic power generally is lowest for the settings the athlete is used to. Based on these findings a change of the athlete's seating position is not expected to lead to an improvement for the athlete.