fig2

Figure 2. Contractile assay methods. (A) Ex vivo (e.g., isolated mouse soleus); (B) In situ (e.g., mouse gastrocnemius); (C) In vivo (e.g., mouse plantar flexors) contractile assessment methods. For In vivo, the arrow indicates the direction of force; (D) Torque is the product of force and the moment arm (MA), where MA is the distance from the axis of rotation to the point where the force is applied. Torque is expressed in millinewtons multiplied by meters (mN·m).