Figure 3 Impact of protein timing on hypertrophy by study, adjusted for total protein intake. Interactions For strength, the interaction between treatment and training status was nearly significant (P = 0.051), but post hoc comparisons between treatment and control within each training status classification were not significant (adjusted P = 0.47 for difference within non-experienced groups, and adjusted
P = 0.99 for difference within experienced groups). There was no significant interaction between treatment and whether groups were protein matched (P = 0.43). For hypertrophy, there was no significant interaction between treatment and training status (P = 0.63) or treatment and protein matching (P = 0.59). Hypertrophy sub-analyses Separating the hypertrophy analysis into CSA or FFM did not materially alter the outcomes. For FFM, there was selleck chemicals no significant difference between treatment and control (difference = 0.08 ± 0.07; CI: -0.07, 0.24; P = 0.27). Total protein intake remained a strong predictor of ES magnitude (estimate = 0.39 ± 0.07; CI: 0.25, 0.53; P < 0.001). For CSA, there was no significant difference between treatment
and control (difference = 0.14 ± 0.16; CI: -0.17, 0.46; P = 0.37). Total protein intake was again a predictor https://www.selleckchem.com/products/S31-201.html of ES magnitude (estimate = 0.55 ± 0.24; CI: 0.08, 1.20; P = 0.02). Discussion This is the first meta-analysis to directly investigate the effects of protein timing on strength and hypertrophic adaptations following long-term resistance training protocols. The study produced several novel findings. A simple pooled analysis of protein timing without controlling for covariates showed a significant effect on muscle hypertrophy (ES = 0.24 ± 0.10) with no significant
effect found on muscle strength. It is generally accepted that an effect size of 0.2 is small, selleck compound 0.5 is moderate, and 0.8 and above is a large, indicating that the effect of protein timing on gains in lean body mass were small to moderate. However, an expanded regression analysis found that any positive effects associated with protein timing on muscle protein accretion disappeared after controlling for covariates. Moreover, sub-analysis showed that discrepancies in total protein intake explained the majority of hypertrophic differences noted in timing studies. When taken together, these results would seem to refute the commonly held belief that the timing of protein intake in the immediate pre- and post-workout period is critical to muscular adaptations [3–5]. Perceived hypertrophic benefits seen in timing studies appear to be the result of an increased consumption of protein as opposed to temporal factors. In our reduced model, the amount of protein DNA Damage inhibitor consumed was highly and significantly associated with hypertrophic gains. In fact, the reduced model revealed that total protein intake was by far the most important predictor of hypertrophy ES, with a ~0.2 increase in ES noted for every 0.5 g/kg increase in protein ingestion.