Plantarflexor force production in isometric and stretch-shortening cycle tasks

The ankle joint and its surrounding musculature are vital in sprinting, and recent work has developed a method to isolate the plantarflexor muscle group for analysis of its force-producing capabilities. The aim of this study was to compare values for plantarflexor force obtained using isometric dynamometry and an adapted force sledge in twenty healthy subjects. Results showed low relationships between isometric and dynamic strength measures, probably because the dynamic test utilises a stretch-shortening cycle. No relationship was observed between isometric strength and the sledge foot plate height during the task with a moderate relationship observed between dynamic strength and plate height. This highlights the important role the Achilles tendon plays in dynamic tasks.