Abstract
We assessed whether a protein supplementation protocol could attenuate running-induced muscle soreness and other muscle damage markers compared to iso-caloric placebo supplementation. A double-blind randomized controlled trial was performed among 323 recreational runners (age 44 ± 11 years, 56% men) participating in a 15-km road race. Participants received milk protein or carbohydrate supplementation, for three consecutive days post-race. Habitual protein intake was assessed using 24 h recalls. Race characteristics were determined and muscle soreness was assessed with the Brief Pain Inventory at baseline and 1–3 days post-race. In a subgroup (n = 149) muscle soreness was measured with a strain gauge algometer and creatine kinase (CK) and lactate dehydrogenase (LDH) concentrations were measured. At baseline, no group-differences were observed for habitual protein intake (protein group: 79.9 ± 26.5 g/d versus placebo group: 82.0 ± 26.8 g/d, p = 0.49) and muscle soreness (protein: 0.45 ± 1.08 versus placebo: 0.44 ± 1.14, p = 0.96). Subjects completed the race with a running speed of 12 ± 2 km/h. With the Intention-to-Treat analysis no between-group differences were observed in reported muscle soreness. With the per-protocol analysis, however, the protein group reported higher muscle soreness 24 h post-race compared to the placebo group (2.96 ± 2.27 versus 2.46 ± 2.38, p = 0.039) and a lower pressure muscle pain threshold in the protein group compared to the placebo group (71.8 ± 30.0 N versus 83.9 ± 27.9 N, p = 0.019). No differences were found in concentrations of CK and LDH post-race between groups. Post-exercise protein supplementation is not more preferable than carbohydrate supplementation to reduce muscle soreness or other damage markers in recreational athletes with mostly a sufficient baseline protein intake running a 15-km road race.
Highlights
Regular physical activities results in a myriad of health benefits, such as a reduced risk for cardiovascular diseases, several cancers, and diabetes [1]
9 participants could not participate in the running event due to illness or injury or did not collect the supplements after the race, resulting in 157 participants in the protein group and 157 participants in the placebo group
On 2 days post-race, 45 participants (39%) of the protein group and 53 participants (44%) of the placebo group performed sports activities (p = 0.40). In this double-blind randomized placebo-controlled trial, we found no greater benefit of protein supplementation on muscle soreness and other muscle damage markers after a 15-km road race compared to the placebo group that received carbohydrate supplementation
Summary
Regular physical activities results in a myriad of health benefits, such as a reduced risk for cardiovascular diseases, several cancers, and diabetes [1]. Other studies failed to replicate these findings in men and women with varying fitness levels and reported no difference in muscle damage markers including muscle soreness between the protein supplementation group and placebo group [10,11,12] This discrepancy could be partly due to a difference in using a study protocol with or without multiple bouts of exercise, since the repeated bout effect could influence the findings. A systematic review concluded that more attention should be given to the effects of different protein sources and timing of supplementation on muscle damage, soreness and recovery of muscle function and physical performance [4] Both casein and whey protein in milk protein contain all essential amino acids required to effectively stimulate muscle protein synthesis [14,15]. These thresholds are often not reached by adults [25,26]
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