Properties of triceps surae and Achilles tendon in forefoot and non-forefoot strike runners.

Background: The purpose of this study was to compare the properties of the triceps surae and Achilles tendon of forefoot strike runners and non-forefoot strike runners.

Methods: Fourteen male college forefoot strike runners and 11 non-forefoot strike runners participated in this study. The shear elastic moduli and cross-sectional areas of the medial and lateral gastrocnemius, soleus, and Achilles tendon were measured. Passive ankle joint stiffness, maximum voluntary isometric contraction on plantar flexion and Rebound Jump Index were also measured.

Results: Forefoot strike runners had higher shear elastic moduli of the medial and lateral gastrocnemius, higher passive ankle joint stiffness, higher Rebound Jump Index, and greater cross-sectional area of the gastrocnemius and Achilles tendon than non-forefoot strike runners.

Conclusions: These findings suggest that forefoot strike runners have different mechanical properties in the gastrocnemius muscles, and different morphological properties in the Achilles tendon and gastrocnemius muscles, compared with non-forefoot strike runners.