Effects of detraining on neuromuscular function and structural adaptations following once- or twice-weekly eccentric resistance training in older adults

Background: Eccentric resistance training elicits greater preservation of training-induced muscular adaptations compared with other training modalities, however the detraining profiles of different training dosages remain unknown. Aims: To examine the detraining effects following once- or twice-weekly eccentric-specific resistance training in older adults. Methods: Twenty-one older adults (age = 70.5 ± 6.0 yr) completed a 12-week detraining period following the 12-week eccentric training programmes with neuromuscular function and muscle structure assessed six (mid-detraining) and 12 (post-detraining) weeks following training cessation. Results: From post-training to post-detraining, no significant regression of the training-induced improvements (collapsed group data reported) occurred in power (0%), strength (eccentric = 0%, isometric = 39%), or explosive strength over numerous epochs (0-32%), resulting in values that remained significantly greater than at pre-training. However, significant regression in the improvements in muscle thickness (91%) and fascicle angle (100%) occurred, resulting in values that were not significantly greater than pre-training. Discussion: The limited regression in neuromuscular function following a 12-week detraining period has important implications for supporting eccentric exercise prescription in older adults who often face periods of inactivity. However, further work is required to develop an effective maintenance dosage strategy that preserves improvements in muscle structure. Conclusions: Eccentric resistance training elicits improvements in the neuromuscular function of older adults, which are sustained for at least 12 weeks after eccentric training cessation.