Fig. 3. Graphs of timing and intensity of muscle activity during a dive–surface cycle with the relative muscle activity of each muscle divided into 100 bins and expressed as means ± s.e.m. for each bin. (A) Diaphragmaticus, N=7; (B) ischiopubis; N=4; (C) rectus abdominis, N=4; (D) internal intercostals, N=2.