Effect Of Carbohydrate-Protein Supplementation On Resistance Exercise Performance, Perceived Exertion, And Salivary Cortisol

Abstract

Research regarding the effectiveness of carbohydrate-protein (CHO-PRO) and carbohydrate (CHO) supplements during resistance exercise (RE) has been inconsistent. PURPOSE: The purpose of this investigation was to determine the effect of CHO-PRO versus CHO supplementation and a placebo (PLA) on RE performance, perceived exertion, and post-exercise salivary cortisol. METHODS: Twenty seven healthy recreational trained males (22.7 ± 2.3 yrs) participated as subjects. Subjects randomly received either a: 1) CHO-PRO; 2) CHO; or 3) PLA supplement 15 min prior to, between every other set, and immediately following RE. The CHO-PRO and CHO supplements were of equal fluid volume and isocaloric. The RE session consisted of seated leg press exercise beginning with 1 set of 10 repetitions at 40, 50, and 60% of 1 repetition maximum (RM), continuing with multiple sets of 8 to 10 repetitions at 70% of 1 RM until fatigue. Ratings of perceived exertion for the active muscle group (RPE-AM) and overall body (RPE-O) were measured immediately following each set and Session-RPE was measured 30 min following the RE session. Salivary cortisol samples were collected 15 min prior to and 30 min following RE. RESULTS: CHO-PRO and CHO supplementation resulted in a significantly greater total number of repetitions performed to fatigue than a PLA. CHO supplementation resulted in attenuated post-exercise salivary cortisol and RPE-AM response at 25% and 50% of total volume of work performed compared to CHO-PRO supplementation or a PLA.TableCONCLUSION: Results suggest that CHO-PRO and CHO supplementation before and during RE can have an immediate beneficial effect and may ultimately lead to enhanced muscular adaptations and improved sport performance.