Effect of combined carbohydrate-protein ingestion on markers of recovery after simulated rugby union match-play

Journal Title (Medline/Pubmed accepted abbreviation): J Sports Sci
Year: 2011
Volume: 29
Number: 12
Page Numbers: 1253-1262

Summary of background and research design:

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.

Summary of research findings:
  • Plasma markers of muscle damage increased following exercise; however, no treatment effect was observed.
    • Creatine kinase levels increased from 258 to 574 U /L at 24 hours after exercise.
    • Myoglobin increased from 50 to 210 nmol/L (P < .05) immediately after exercise.
  • Salivary cortisol and testosterone levels decreased following exercise; however, no treatment effect was observed.
  • Muscle soreness increased immediately after (rating = 2) and 24 hours after (rating = 3) exercise compared with before exercise (rating = 1; maximum rating = 8).
  • Leg strength and repeated 6-second cycle sprint mean power were slightly reduced immediately after exercise (93% and 95% of pre-exercise values, respectively; P < .05), but were almost fully recovered by 24 hours after exercise (97% and 99% of pre-exercise values, respectively).
  • There were no differences between trials for any measure.

Interpretation of findings/Key practice applications:

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.


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