Nutrient recovery of contractile function following resistance exercise

Resistance exercise training (RXT) induces neuromuscular adaptation, increasing contractile function. However, immediately following RXT, a decrease in function occurs, followed by a temporal pattern of recovery. The modality of RXT determines the magnitude of the dysfunction and recovery pattern. Dietary nutrient supplementa?tion is purported to be remedial for recovery. Efficient recovery between RXT bouts is required to optimise performance. The purpose of this research is to directly inves?tigate the effect of nutrient supplementation on the recovery of contractile function following RXT. An ecologically valid RXT-model was constructed, validated, and implemented to characterise the recovery of function in trained young men and women. Impaired contractile function was observed up to 48 h following RXT, dys?function was greater and prolonged in women compared to men (e.g. -4 % c.f. -27 %, 48 h post-RXT). Remodelling necessitates the recovery of function following RXT. Whey protein supplementation is known to accelerate remodelling, but the effect on the restoration of contractile function is not known. This was tested using the same RXT-model. Compared to a control, whey protein supplementation had no effect on the recovery of contractile function 24 to 48 h following RXT, suggesting disruption to regulatory processes outside of the contractile unit, viz. impaired calcium release. Caffeine increases central drive potentiating calcium release. Adopting a scaled unilateral RXT model, it was demonstrated that caffeine restored contractile force 1 h following RXT compared to a placebo (-13 % c.f. -1 % post-RXT). These data suggest that the contractile dysfunction observed following accustomed, ecologically valid XT is not limited by change to the contractile unit per se, but rather impairment of the physiological processes proximal to the contractile unit.