Journal Title (Medline/Pubmed accepted abbreviation): J Sports Sci
Page Numbers: 1253-1262
Background:Physical impacts coupled with the mechanical and metabolic stresses experienced during rugby union match-play cause muscle damage evidenced by increased plasma creatine kinase and myoglobin. Interventions that limit muscle damage may relieve pain, prevent limitations of muscle function, and speed recovery of athletes. After exercise, ingestion of carbohydrates (CHO) replenishes glycogen stores, whereas ingestion of protein (PRO) during or after exercise reduces perception of soreness, decreases systemic markers of muscle damage, and speeds recovery of muscle function.
Hypothesis/Purpose of study: To examine the effects of CHO and combined CHO+PRO ingestion on muscle damage, performance recovery, and salivary cortisol and testosterone concentrations in rugby players after simulated rugby union match-play.
Subjects: Nine experienced male rugby union players (mean age, 21.8 ± 3.3 y; height, 183 ± 5 cm; body mass, 93.3 ± 13.7 kg; playing experience, 12 ± 4 y) volunteered for study participation.
Experimental design: Randomized, cross-over
Treatments and protocol:
On 3 occasions, at least 1 week apart in a counterbalanced order, male rugby union forwards ingested liquid containing CHO (1.2 g/kg/hr) or CHO (1.2 g/kg/hr) with PRO (0.4 g/kg/hr) or placebo (containing aspartame), before, during, and after a rugby union-specific protocol. The initial 500 mL bolus was consumed 1 hour before exercise; remaining solution (mean volume, 1,157 ± 235 mL) was divided into 3 equal portions for consumption during exercise rest periods between blocks 1 and 2, blocks 2 and 3 (halftime), and blocks 3 and 4 of the Bath University Rugby Shuttle Test (BURST; 16 × 315-sec exercise periods grouped into 4 × 21-min blocks consisting of repeated exercise and contact tasks including alternating scrummaging, rucking, and mauling tasks interspersed with performance tests including strength [bench press, bench pull, and leg press], vertical jumps, and repeated sprint tests [stationary bicycle]). One hour after completing the exercise protocol, participants received additional placebo, CHO, or CHO+PRO solution consistent with the volume ingested over 1 hour of exercise (mean volume, 1,128 ± 416 mL). Participants rated their whole body active soreness and individual muscle group soreness both before and after exercise. Blood (creatine kinase activity and myoglobin concentration) and saliva (testosterone and cortisol concentrations) samples were taken before and after exercise periods.
In trained rugby players, ingestion of CHO or CHO+PRO did not attenuate the muscle damage and reduction in muscle function caused by a simulated rugby union match-play. The authors concluded that individuals experienced in a given exercise program do not benefit from co-ingestion of CHO+PRO before, during or after exercise in terms of reducing muscle damage or speeding recovery of muscle function.