PP1 activity in the triceps muscle was assayed as described in `Materials and Methods'. Protein expression was measured by immunoblotting. Within each group, data are expressed relative to sedentary. (A) PP1 activity (B) PP1c protein expression, and (C), RGL(GM) protein expression. Results are means ± S.E., n = 6–12/group. *, P<0.05 versus sedentary, **, P<0.01 versus sedentary.