Figure 1.

The six participants from Study 1 who performed single or repeated bouts of acute moderate intensity strengthening exercise did not demonstrate any clinically meaningful increases in creatine kinase (CK) levels. Values are shown before (Baseline) and after a single bout (Subjects 1-4 from Experiment 2) or after 3 bouts (Subjects 5 and 6 from Experiment 3) of exercise. Each bout consisted of four sets of six repetitions of isometric knee extensor and knee flexor exercise at both 30 and 60 degrees of knee flexion at an intensity of 50% maximal volitional contraction (MVC).