Figure 2.

The effect of greater shortening velocity on muscle activation to achieve a target force. The force-velocity relationship, scaled to maximal isometric force (Po) and maximal velocity of shortening (V_max) (Chow and Darling, 1999). The short dashed and solid lines represent 50 and 85% of maximal motor unit activation, respectively. The long dashed line represents maximal activation. When force can be generated isometrically, target force (P) can be achieved with minimal motor unit activation, as shown by the open square. When shortening is permitted, additional motor unit activation is required (filled square). Used with kind permission of Springer Science+Business Media.