Comparison of cross-sectional area max (CSAmax) between COL6-RD, DMD and control groups. +significantly different from control; * significantly different from COL6 p < 0.05; COL6-RD-Collagen VI related dystrophy, DMD- Duchenne Dystrophy, VIVastus Intermedius, VL- Vastus Lateralis, VM- Vastus Medialis, RF- Rectus Femoris, Sol- Soleus, MG- Medial Gastrocnemius, LG- Lateral Gastrocnemius.