Figure 2.

(A) ATP cost of contraction during submaximal plantar flexion exercise in the young, old, and oldest-old participants, (B) the relationship between the maximal work rate reached during an incremental plantar flexion exercise and the ATP cost of contraction during submaximal plantar flexion exercise [young (empty circles, female = 6; male = 5; n = 11), old (gray circles, female = 6; male = 5; n = 11), and oldest old (black circles, female = 4; male = 6; n = 10)]. Values are presented as mean ± SEM. *p < .05, significantly different from the old and young.