Sonographic studies of human soleus and gastrocnemius muscle architecture:gender variability

The purpose of this study was to establish if there are gender differences in muscle architecture in relaxed human soleus and gastrocnemius muscles of normal, live subjects. Ultrasonography was used to measure fiber bundle le ngth muscle thickness, and angles of pennation in a total of ten predetermi ned sites in the medial and lateral heads of gastrocnemius and the anterior and posterior soleus in 19 males and 16 females. Percentage differences be tween males and females for each parameter were recorded. Gender difference s were statistically analyzed using multivariate analysis of variance. In t he gastrocnemius and soleus muscles of males and females the differences be tween the overall fiber bundle length, angle of pennation and muscle thickn ess were statistically significant (P < 0.05). Overall, females were found to have longer average muscle fiber bundle length and males thicker muscles and larger angles of pennation. The greatest percentage differences of the architectural parameters between males and females were in the posterior s oleus: 13% difference in fiber length and 26% difference in angle of pennat ion in the midline of posterior soleus and 26% difference in muscle thickne ss of the lateral parr of posterior soleus. No correlation was found betwee n leg length and fiber length, angle of pennation or muscle thickness. Fibe r length (decreased), angle of pennation (greater) and muscle thickness (gr eater) of most parts of the gastrocnemius and soleus muscles were significa ntly different in males and females. Leg length of males and females did no t correlate to these architectural parameters.