LAUSR

Purpose To examine the effects of fatigue on inter-joint coordination during repeated ballet jumping ( petit échappé sauté ). Methods Twenty female ballet dancers performed petit échappé sauté movements up to and beyond the point of fatigue . The petit échappé sauté movement and the hip-knee joint and knee-ankle joint coordination in the non-dominant leg was evaluated across the six sub-phases using a continuous relative phase measure. The six sub-phases were classified as follows: Phase1: initial takeoff phase from 1st position, Phase 2: the top of center of mass (COM) position from 1st to 2nd position, Phase 3: the terminal landing phase to 2nd position, Phase 4: initial takeoff phase from 2nd position, Phase 5: the top of COM position from 2nd to 1st position, and Phase 6: the terminal landing phase to 1st position. Phase deviations were used to quantify the movement pattern and inter-joint coordination variability, where larger deviation values meant a more variable relationship between the two joints. Results The dancers exhibited greater phase deviations during landing at a wider base of support, but a lower phase deviation at a narrower base of support following fatigue. The dancers showed less consistent inter-joint coordination between the hip and knee and between the knee and ankle following fatigue during phases 2 and 5 (airborne phase) and phase 4 (lowest center of mass phase). Conclusion The present results suggest that the inter-joint coordination deteriorated during relatively difficult phases, and this change may put dancers at risk for injury.