Coupling angle variability of upper extremity during 5 weeks overarm throwing self-practice

The role of variability is still unknown for biomechanists whether it's useful or not for the performance or skill learning. The aim of this study was to investigate coupling angle variability (CAV) at the early phase of skill acquisition of overarm throwing without any feedback about the result or performance. 7 healthy female without any throwing experience participated in this study. Each participant participated a total of 15 sessions in the laboratory (3 days in a week x 5 weeks). Coupling angle variability of angle-angle diagrams (AAD) calculated for combinations of trunk flexion (TF) –lateral flexion(TL), humeral elevation (HE)- humeral plane of elevation (HP), elbow flexion-extension(EF). There were no significant changes for CAV, however individual AADs showed different patterns for each individual. For understanding the role of the variability in skill learning or performance, individual variability analysis may give information better than the group means