Groeller, H., & Sampson, J. (2009). The effect of detraining on muscle strength and cross-sectional area following unilateral resistance training. ACSM 56th Annual Meeting, Seattle, Washington. Presentation number 727.

red line

"Muscle strength appears well preserved following short periods of detraining, despite a decline in muscle cross-sectional area and muscle activation." This study determined the effect a 12-week unilateral elbow flexor resistance training regimen followed by eight weeks of detraining on muscle cross-sectional area, muscle activation, and dynamic and static strength in trained and non-exercising contralateral limbs. Males (N = 10) completed a four-week pre-treatment training period (50-80%1 RM) before commencing the experimental resistance training regimen. Ss attended three sessions per week for 12 weeks of experimental training. They exercised at 85%1 RM. Each S's trained limb and contralateral limb was assessed for 1 RM, maximum voluntary contraction, and EMG at baseline, after 12 weeks of training, and at four and eight weeks of detraining. Muscle cross-sectional area was determined by MRI at baseline, after experimental training, and at eight weeks of detraining in six Ss.

Muscle cross-sectional area, 1 RM, maximum voluntary contraction, and muscle activation declined in the trained limb after eight weeks of detraining. In contrast, after detraining no significant decline was observed in contralateral limb 1 RM. Additionally, trained limb 1 RM, maximum voluntary contraction strength, and muscle activation after detraining remained significantly elevated over baseline values. These changes were observed despite a decline in muscle cross-sectional area over the same period.

Implication. Dynamic and static strength declined following detraining but not to pretraining values. The decline in muscle activation and muscle cross-sectional area appears to contribute to the loss of strength. In contrast, neurally mediated gains in dynamic strength of the contralateral limb did not decline.

Return to Table of Contents for this issue.

red line