Fig. 2.
Metabolic changes in medial gastrocnemius PCr (a, b) and pH (c, d) during contraction and recovery in young and older men (a, c) and women (b, d). PCr is expressed relative to resting values. The end of the 20-s contraction is indicated by the dashed vertical line. Recovery of PCr following contraction in MG was well approximated by a monoexponential function (r 2 = 0.89 ± 0.09, 0.92 ± 0.02, 0.86 ± 0.09, and 0.89 ± 0.06 for YM, OM, YW, OW, respectively). Error bars indicating SD are provided every 24 s during recovery, for clarity