The Impact of Muscle Length on Postexercise Recovery Following Isometric Exercise in Active Women: An Explorative Study

Purpose: The muscle length at which isometric exercise is performed in uences both acute effects and chronic adaptations. However, most of the investigations have been conducted on men only, and no studies have examined the performance impairments and the recovery time course following isometric exercise protocols at long (LML) and short muscle length (SML) in women. Methods: This study aimed to compare the acute effects of LML and SML isometric exercise in women. Ten active women (age: 24.5 ± 1.4 years; height: 166.4 ± 6.7 cm; body mass: 62.5 ± 7.4; training experience: 5.0 ± 2.7) performed a maximum effort isometric exercise session for the pectoralis major muscle at LML or SML in random order. Peak force at LML and SML, average power at bench throw test, muscle thickness, corrected echo intensity, and muscle soreness were assessed before and 15-min, 24-hr, and 48-hr postexercise. Rate of perceived effort was also assessed 15-min postexercise. Results: No Condition × Time interactions were detected for peak force (p > .678), bench throw test (p = .316), and for corrected echo intensity (p = .557). However, higher increase in muscle thickness was observed 15-min postexercise in LML compared to SML (p = .02; g = 0.60). Muscle soreness was also higher 15 min (p = .009; g = 1.53), 24 hr (p = .01; g = 1.42), and 48 hr (p = .02; g = 1.04) following LML compared to SML. No significant differences in rate of perceived effort were detected between the two protocols (p = .771). Conclusions: Although similar patterns of muscle recovery were observed for strength and average power, LML exercise protocol induced more muscle swelling and soreness than SML in active women.