Comparison of Carbohydrate and Milk-Based Beverages on Muscle Damage and Glycogen Following Exercise

Abstract

This study examined effects of carbohydrate (CHO), milk-based carbohydrate-protein (CHO-PRO), or placebo (P) beverages on glycogen resynthesis, muscle damage, inflammation, and muscle function following eccentric resistance exercise. Untrained males performed a cycling exercise to reduce muscle glycogen 12 hours prior to performance of 100 eccentric quadriceps contractions at 120% of 1-RM (day 1) and drank CHO (n = 8), CHO-PRO (n = 9; 5 kcal/kg), or P (n = 9) immediately and 2 hours post-exercise. At 3 hours post-eccentric exercise, serum insulin was four times higher for CHO-PRO and CHO than P (p < .05). Serum creatine kinase (CK) increased for all groups in the 6 hours post-eccentric exercise (p < .01), with the increase tending to be lowest for CHO-PRO (p < .08) during this period. Glycogen was low post-exercise (33+/-3.7 mmol/kg ww), increased 225% at 24 hours, and tripled by 72 hours, with no group differences. The eccentric exercise increased muscle protein breakdown as indicated by urinary 3-methylhistidine and increased IL-6 with no effect of beverage. Quadriceps isokinetic peak torque was depressed similarly for all groups by 24% 24 hours post-exercise and remained 21% lower at 72 hours (p < .01). In summary, there were no influences of any post-exercise beverage on muscle glycogen replacement, inflammation, or muscle function.

Dietary macronutrient recommendations for optimal recovery post-exercise: Part I

“…Furthermore, Tarnopolsky and coworkers 48 found significantly higher glycogen concentrations (4 hours post-exercise) after ingesting a CHO-only (1 g CHO/kg BW/serving) compared with an isocaloric CHO-protein (0.75 g CHO + 0.1 g protein + 0.02 g fat/kg BW/serving) supplement after a glycogen-depleting exercise protocol. These results are supported Wojcik and co-workers, 56 and may suggest that insulin is not the rate-limiting factor for muscle glycogen synthesis when the overall rate of CHO intake is high (> 1 g CHO/kg BW/hour).…”

Metabolismo do glicogênio muscular durante o exercício físico: mecanismos de regulação

“…Os autores sugeriram que o maior nível de insulina poderia aumentar a síntese de glicogênio muscular. Alguns autores demonstraram que a inclusão de proteínas na refeição pós-esforço acelera a reposição do glicogênio muscular 46 , mas nenhum efeito dessa estratégia foi observado por Wojcik et al 47 , comparando suplementação de carboidrato com proteína + carboidrato. Portanto, a eficácia da ingestão de proteínas em conjunto com carboidratos, sobre a reposição do glicogênio muscular, é uma questão ainda não esclarecida.…”

A comparison of the effects of milk and a carbohydrate-electrolyte drink on the restoration of fluid balance and exercise capacity in a hot, humid environment

“…Previous investigations administering milk following exercise have looked at muscle protein synthesis (Elliot et al 2006), muscle function and glycogen synthesis (Wojcik et al 2001). Karp et al (2006) reported a greater restoration of exercise capacity following the ingestion of chocolateXavoured milk, when compared to a CHO replacement solution of a similar macronutrient composition.…”