Neuromuscular recovery from severe- and extreme-intensity exercise in men and women.

Maximal voluntary contraction force (MVC), potentiated twitch force (Q), and voluntary activation (%VA) recover to baseline within 90 s following extreme-intensity exercise. However, methodological limitations mask important recovery kinetics. We hypothesized reductions in MVC, Q, and %VA at task failure following extreme-intensity exercise would be less than following severe-intensity exercise, and Q and MVC following extreme-intensity exercise would show significant recovery within 120 s but remain depressed following severe-intensity exercise. Twelve subjects (6 men) completed 2 severe-intensity (40, 50% MVC) and 2 extreme-intensity (70, 80% MVC) isometric knee-extension exercise bouts to task failure (T). Neuromuscular function was measured at baseline, T, and through 150 s of recovery. Each intensity significantly reduced MVC and Q compared with baseline. MVC was greater at T ( < 0.01) and at 150 s of recovery ( = 0.004) following exercise at 80% MVC compared with severe-intensity exercise. Partial recovery of MVC and Q were detected within 150 s following T for each exercise intensity; Q recovered to baseline values within 150 s of recovery following exercise at 80% MVC. No differences in %VA were detected pre- to post-exercise or across recovery for any intensity. Although further analysis showed sex-specific differences in MVC and Q, future studies should closely examine sex-dependent responses to extreme-intensity exercise. It is clear, however, that these data reinforce that mechanisms limiting exercise tolerance during extreme-intensity exercise recover quickly. Severe- and extreme-intensity exercise cause independent responses in fatigue accumulation and the subsequent recovery time courses. Recovery of MVC and Q occurs much faster following extreme-intensity exercise in both men and women.