The Efficacy of Prehabilitative Conditioning Ameliorating Unloading-Induced Declines in the Muscle Function of Humans

Objective: To determine whether prehabilitation, or exercise performed before muscle unloading, can effectively mitigate decreases in neuromuscular function typically elicited by unloading. Design: Ten healthy, untrained young men (20.9 +/- 1.3 yrs; mean +/- SD) were initially tested for strength, work, power, and electromyography. After completing six prehabilitative resistance training sessions, they repeated testing of neuromuscular function. Immediately after the second neuromuscular function test, participants began 7 days of muscle unloading that was immediately followed by a third testing session for neuromuscular function. Results: Prehabilitative conditioning failed to prevent significant (P <= 0.05) unloading-induced decrements in neuromuscular function. Performance in each measure quantified was significantly less during the third test session than during both of the first two sessions. Moreover, the declines in strength observed here were similar to those noted in a previous study featuring 1 wk of unloading without prehabilitation (13% vs. 16%, respectively, P > 0.05). Also similar to that study, the decline in strength noted here was significantly correlated with a decline in electromyography. Conclusions: The prehabilitation program used here did not moderate unloading-induced reductions in neuromuscular function. It remains to be determined whether more extensive prehabilitation protocols may be more effective.