Age and Sex Effects on the Active Stiffness of Vastus Intermedius under Isometric Contraction

Figure 3

The mean VI shear modulus at different relative isometric contraction levels (% MVC) and different knee joint angles (90° and 60°) with the corresponding quadratic regression fitting curves for (a) young male subjects; (b) young female subjects; (c) elderly male subjects; and (d) elderly female subjects.

(a)

(b)

(c)

(d)