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

In this study, we investigated the effect of ingesting carbohydrate alone or carbohydrate with protein on functional and metabolic markers of recovery from a rugby union-specific shuttle running protocol. On three occasions, at least one week apart in a counterbalanced order, nine experienced male rugby union forwards ingested placebo, carbohydrate (1.2 g · kg body mass(-1) · h(-1)) or carbohydrate with protein (0.4 g · kg body mass(-1) · h(-1)) before, during, and after a rugby union-specific protocol. Markers of muscle damage (creatine kinase: before, 258 ± 171 U · L(-1) vs. 24 h after, 574 ± 285 U · L(-1); myoglobin: pre, 50 ± 18 vs. immediately after, 210 ± 84 nmol · L(-1); P < 0.05) and muscle soreness (1, 2, and 3 [maximum soreness = 8] for before, immediately after, and 24 h after exercise, respectively) increased. Leg strength and repeated 6-s cycle sprint mean power were slightly reduced after exercise (93% and 95% of pre-exercise values, respectively; P < 0.05), but were almost fully recovered after 24 h (97% and 99% of pre-exercise values, respectively). There were no differences between trials for any measure. These results indicate that in experienced rugby players, the small degree of muscle damage and reduction in function induced by the exercise protocol were not attenuated by the ingestion of carbohydrate and protein.

Effects of carbohydrate and caffeine ingestion on performance during a rugby union simulation protocol.

In this study, we investigated the effect of ingesting carbohydrate alone or with caffeine on performance of a rugby union-specific shuttle running protocol. On three occasions, at least one week apart in a counterbalanced trial order, eight male rugby union forwards ingested either placebo or carbohydrate (1.2 g x kg(-1) body mass x h(-1)) before and during a rugby union-specific protocol, with pre-exercise caffeine ingestion (4 mg x kg(-1)) before one of the carbohydrate trials (carbohydrate + caffeine). The intermittent exercise protocol included walking, jogging, and cruising at pre-determined intensities, simulated contact events, a sustained high-intensity test of speed and agility (Performance Test), and a 15-m sprint. Ratings of perceived exertion (RPE) were recorded every 5 min and a motor skills test was performed after each 21-min block. Performance Test times were not significantly different between trials but the likelihood of 2% improvements for carbohydrate + caffeine over placebo and carbohydrate were 98% and 44%, respectively. For carbohydrate + caffeine, 15-m sprints were faster than for placebo (P=0.05) and the motor skills test was performed faster in the carbohydrate + caffeine trial than the carbohydrate and placebo trials (P < 0.05), while RPE was lower in the carbohydrate + caffeine trial than the carbohydrate and placebo trials (P < 0.05). The results indicate a likely benefit to rugby performance following co-ingestion of carbohydrate and caffeine.