Post-exercise ingestion of a carbohydrate and casein hydrolysate supplement reduces perceived muscle soreness but not fatigue in Sevens Rugby Players

Abstract

Objectives. This study investigated the effects of prolonged use of a protein (casein hydrolysate) supplement on perceived muscle soreness and fatigue, in international level Sevens rugby players (n=23) during a pre-season training camp. Methods. A randomised, double-blind, placebo-controlled design was used. Players were assigned to a carbohydrate-only or an isocaloric carbohydrate and protein supplement and ingested the assigned supplement after each training session (17 field training sessions over a 23-day period). Before each training session a questionnaire and 10-point visual analogue scale was completed that assessed muscle soreness and muscle fatigue in the calf, hamstring, and quadriceps. Results. No significant differences were observed in leg fatigue in any of the muscle groups. However, muscle soreness was significantly lower in the experimental group in the quadriceps at Week 3, Day 5 (p=0.04) and calves at Week 4, Day 2 (p=0.02) and Day 3 (p=0.04). Additionally, no significant differences were found during the Heart rate Interval Monitoring System Test (p=0.350) used to determine training load recovery. Conclusion. The results suggest that prolonged use of a protein hydrolysate supplement may be beneficial in reducing muscle soreness, but not muscle fatigue, during periods of continuous high training loads. Keywords. Supplement, protein feeding, recovery