Kinematic Analysis of a Series of Jumps In First Position In Professional Ballet Dancers

Purpose: Few ballet-specific studies in the literature examine kinematics during dance activities. Sports studies have identified injury risk in athletes by observing kinematics during specific activity, but this has not yet been explored for ballet. Evaluating kinematics in dancers has the potential to identify injury risk and influence treatment for prevention and rehabilitation. Therefore, the purpose of this study was to examine the landing kinematics of professional ballet dancers during a series of 16 ballet-specific jumps. Methods: This study was a multi-factor repeated measures design. Participants (3 males, 16 females aged 19-33 years; first or second company members) performed 16 consecutive sautés in first position to a metronome set at 120 beats per minute. Lower extremity kinematic data was captured using the Noraxon myoMOTIONTM system and was analyzed at peak knee flexion of landing on jumps 1, 8, and 15 for hip abduction (HA), hip flexion (HF), and hip external rotation (HER). Analyses included: right versus left side differences (RvL), differences between jumps 1, 8, and 15, and interaction between the specific jump and RvL. Results: Statistically significant differences (SD) were found in: RvL HA (p=0.000, 10.68 degrees; clinically relevant) and in HF between jumps 1 and 8 (p=0.000) and 1 and 15 (p=0.006). There was no interaction effect of HA between jump number and RvL (p=0.470) or of HER between jump number and RvL (p=0.599). There was no SD in: HF between jumps 8 and 15 (p=0.245), HA between jumps (p=0.062), RvL HF (p=0.190), RvL HF between jumps (p=0.972), HER between jumps (p=0.366), or RvL HER (p=0.562). Conclusions: The RvL difference in HA (p=0.000) suggests asymmetrical loading of hip joints. This difference did not change between jumps (p=0.062), suggesting repeated preferential frontal plane loading. The SD in HF between jumps 1 and 8 (p=0.000) and 1 and 15 (p=0.006) suggests that a small series of jumps that are standard in ballet class are not consistent motions for professional dancers. Limitations include small sample size and lack of controlled warm up. Future work should examine single leg jumps or sautés following a fatigue protocol to assess joint motion more accurately