Effect Of Protein Supplementation On Running Exercise-induced Muscle Damage And Soreness: A Randomized Controlled Trial

Abstract

PURPOSE: The benefits of protein supplementation on endurance exercise-induced muscle damage and soreness remain inconclusive. Therefore, we assessed whether a protein supplementation protocol with optimized timing and amounts could attenuate running-induced muscle soreness and muscle damage compared to iso-caloric placebo supplementation. METHODS: A double-blind randomized controlled trial was performed among 323 recreational runners (age 44±11 years, 56% male) participating in a 15-km road race. Participants received 2 supplements per day containing 80% caseinate and 20% whey protein (intervention) or carbohydrate (placebo). Supplements were consumed post-race (at the finish line and prior to sleep) and during 3 consecutive days (at breakfast and prior to sleep). Habitual protein intake was assessed using 24hr recalls at baseline, on the day of the race and 1, 2 and 3 days post-race. Race characteristics were determined and muscle soreness was assessed with the Short-Form Brief Pain Inventory at baseline and 1 day, 2 days and 3 days post-race. In a subgroup (n = 149), muscle soreness was measured with a strain gauge algometer and concentrations of the muscle damage markers creatine kinase (CK) and lactate dehydrogenase (LDH) were measured 25 to 48hr post-race. RESULTS: At baseline, no group-differences were observed for habitual protein intake (79.9±26.5 g/d versus 82.0±26.8 g/d, P=0.49) and Numeric Pain Rating Scale muscle soreness (0.45±1.08 versus 0.44±1.14, P=0.96) in the protein group compared to the placebo group. Subjects completed the race at an exercise intensity of 94±6% of HRmax and a running speed of 12±2 km/h. The protein group reported higher muscle soreness 24hr post-race compared to the placebo group (2.96±2.27 versus 2.46±2.38, P=0.039), but no differences were observed on day 2 and 3 post-race. Similarly, we found a lower pressure pain threshold for the quadriceps muscle in the protein group compared to the placebo group (71.8±30.0 N versus 83.9±27.9 N, P=0.019). Similar concentrations of CK and LDH were found post-race in both groups. CONCLUSION: Post-exercise protein supplementation is not more preferable than carbohydrate supplementation to reduce muscle soreness or damage in recreational athletes with a protein intake of 1.14 ± 0.35 g/kg/d running a 15-km road race.