Statistical analysis of muscle fibre types from four human skeletal muscles

The joint distributions of the different muscle fibre types were investigated in human diaphragm temporalis, gastrocnemius and soleus muscles. (1) "Independence" was found between "white and intermediate" fibres in the diaphragm muscle; "red and intermediate" fibres in the temporalis muscle and "red and white" fibres in the soleus muscle. (2) An almost "linear relationship" was observed between red and intermediate fibres in both the diaphragm and soleus muscles and red and white fibres of temporalis muscle. (3a) In the diaphragm and soleus, the distribution of intermediate and red fibres exhibited large variation between different samples; unlike that shown by the white fibres. (3b) In the temporalis large variation was evident in the distribution of white and red fibres between samples; the intermediate fibre type showed minimal variation. (3c) No particular relationship was evident between different fibre types of the gastrocnemius muscle. The distribution of muscle fibres in all the 4 human muscles is "singular trivariate normal".