Consecutive Single-Leg Relevés Results in Altered Movement Pattern and Dorsiflexor and Plantarflexor Muscle Fatigue.

Aim: This study investigated how muscle activation and movement altered as a result of dorsiflexor and plantarflexor muscle fatigue in dancers during single-leg relevés.

Methods: 14 participants with current or recent experience in dance performed 10 single-leg relevés before and after a fatigue protocol at a set tempo of 46 beats per minute. The pre-fatigue and post-fatigue differences were assessed via surface electromyography of the lateral gastrocnemius, medial gastrocnemius, soleus, and tibialis anterior during the ascending and descending phases. Kinematic data was obtained and assessed using 3D motion capture technology.

Results: No significant differences in muscle activation occurred from pre-fatigue to post-fatigue during the ascending phase. However, there was a significant increase in activation during the descending phase in both the soleus (P = .020) and lateral gastrocnemius (P = .028). Additionally, there was a significant decrease in ankle range of motion (P = .004) and heel height achieved (P = .006) from pre-fatigue to post-fatigue. There was also a significant decrease in ankle dorsiflexion (P < .001) and plantarflexion (P = .014) post-fatigue.

Conclusion: Overall, ankle plantarflexor fatigue results in an inability to maintain movement despite increased muscle activation. Future research could support in validating the findings that dancers should limit working past or near fatigue, as it could lead to increased mechanical compensations which increase the risk of injury.