The effect of short-term consumption of carbohydrate-protein smoothies during recovery on muscular performance in recreational athletes

This study was conducted to determine the effect of short-term consumption of a carbohydrate-protein smoothie during recovery on muscle performance in male recreational athletes. In this study, a randomized, double-blind crossover design, 12 male recreational athletes voluntarily participated. Before the intervention, isokinetic parameters of the knee extensors and flexors, including peak isokinetic torque (PT) at 60 degrees/s and mean rate of force development (RFD), were measured using a Biodex dynamometer to determine baseline levels. All participants then participated in 3 separate sessions of muscle injury induction (EIMD) with a 1-week interval as a washout period. After each session, subjects randomly and in a crossover design consumed 350 ml of milk + banana (MB), milk + banana flavor (M), or placebo consisting of water + banana flavor milk (PLA). In addition, delayed onset muscle soreness (DOMS) was assessed immediately, 24, and 48 hours after EIMD using a visual analog scale (VAS). Data collected using SPSS software were analyzed at the P<0.05 level using repeated measures analysis of variance and Bonferroni post hoc test. The findings of the present study showed that PT of knee extensors in the placebo condition was significantly reduced compared to baseline levels (P<0.05), while in the MB and M conditions there was no significant difference from baseline levels (P>0.05). In addition, milk or milk + banana consumption after EIMD significantly increased PT of knee extensors compared to placebo (P<0.05). No significant changes were observed in PT of knee flexors and mean RFD of knee extensors (P>0.05). However, the mean RFD of knee flexors after M and MB was significantly better than PLA (P<0.05), but compared to baseline levels, none of the conditions caused significant changes (P>0.05). The findings related to DOMS also showed that DOMS values in all three conditions decreased significantly 48 hours after EIMD (P>0.05), but no significant changes were observed 24 hours after EIMD (P>0.05). Taken together, these findings indicate that consuming protein or protein + carbohydrate drinks can help improve muscle recovery.