Whey protein's effects on post-resistance training muscle function recovery still uncertain: Review
Although whey protein is widely consumed in order to improve strength and muscle mass during resistance training, its effectiveness in promoting recovery of muscle function after resistance training is less well-known.
Post-resistance training, muscle protein anabolism is acutely elevated, and is further enhanced by whey protein. This implies that supplementation with whey protein may be a suitable nutritional option to restore the acute loss of contractile function after vigorous resistance training.
Consistent but insufficient results
Based on this, researchers at the University of Limerick in Ireland conducted a systematic review and meta-analysis of papers published so far detailing the impact of whey protein supplementation on contractile function recovery in young, healthy adults.
Their review and analysis consisted of eight studies containing 13 RCTs, from which they calculated individual standardised effect sizes, and a temporal overall effect size was determined via a random-effects model.
They then noted that only half of the individual studies had reported positive effects of whey protein supplementation, while the "high-quality evidence" gathered from the 13 RCTs, after meta-analysis, showed "overall positive small to medium effects" of whey protein supplementation on the temporal restoration of contractile function when compared with the control groups.
Whey protein supplementation did indeed have a temporal ergogenic effect in terms of accelerating the recovery of muscle function after resistance training, but despite the general consistency observed over time, the researchers said more comprehensive research in this area would be needed.
They also said that the limited findings meant the results were "under-powered for further analysis / control of other extraneous and / or potentially confounding factors, such as the subject characteristics, mode / purpose of exercise, and / or the supplementation strategy".
Furthermore, they stated that they would "caution against interpreting the overall temporal effect size reported in this study as definitive evidence".
In conclusion, they wrote: "Rather, it is suggested these findings are understood as a synthesis of the literature to date, reflecting the dispersion, limitations, and overall effects between the RCTs in the extant literature, identifying the need for further experimental research in this area."
"The Effect of Whey Protein Supplementation on the Temporal Recovery of Muscle Function Following Resistance Training: A Systematic Review and Meta-Analysis"
Authors: Robert W. Davies, et al.