Carbohydrates are critical for high‐intensity exercise performance. However, the effects of carbohydrate supplementation on muscle metabolism and performance during short‐duration high‐intensity intermittent exercise remain inadequately explored. Our aim was to address this aspect in a randomized, counterbalanced, double‐blinded crossover design. Eleven moderately‐to‐well‐trained males performed high‐intensity intermittent cycling receiving carbohydrate (CHO, ~55 g/h) or placebo (PLA) fluid supplementation. Three exercise periods (EX1‐EX3) were completed comprising 10 × 45 s at ~105% Wmax interspersed with 135 s rest between bouts and ~20 min between periods. Repeated sprint ability (5 × 6 s sprints with 24 s recovery) was assessed at baseline and after each period. Thigh muscle biopsies were obtained at baseline and before and after EX3 to determine whole‐muscle and fiber‐type‐specific glycogen depletion. No differences were found in muscle glycogen degradation at the whole‐muscle (p = 0.683) or fiber‐type‐specific level (p = 0.763–0.854) with similar post‐exercise whole‐muscle glycogen concentrations (146 ± 20 and 122 ± 15 mmol·kg−1 dw in CHO and PLA, respectively). Repeated sprint ability declined by ~9% after EX3 with no between‐condition differences (p = 0.971) and no overall differences in ratings of perceived exertion (p = 0.550). This was despite distinctions in blood glucose concentrations throughout exercise, reaching post‐exercise levels of 5.3 ± 0.2 and 4.1 ± 0.2 mmol·L−1 (p < 0.001) in CHO and PLA, respectively, accompanied by fivefold higher plasma insulin levels in CHO (p < 0.001). In conclusion, we observed no effects of carbohydrate ingestion on net muscle glycogen breakdown or sprint performance during short‐duration high‐intensity intermittent exercise despite elevated blood glucose and insulin levels. These results therefore question the efficacy of carbohydrate supplementation strategies in high‐intensity intermittent sports.

中文翻译：

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在短时间高强度间歇运动期间，碳水化合物摄入对肌肉代谢或表现没有影响


碳水化合物对于高强度运动表现至关重要。然而，补充碳水化合物对短时高强度间歇运动期间肌肉代谢和表现的影响仍未得到充分研究。我们的目标是通过随机、平衡、双盲交叉设计来解决这个问题。 11 名接受过中等至良好训练的男性进行了高强度间歇性骑行，接受碳水化合物（CHO，约 55 克/小时）或安慰剂 (PLA) 液体补充。完成三个运动周期 (EX1-EX3)，包括 10 × 45 秒，最大 Wmax 为 105%，间歇期之间休息 135 秒，周期之间休息约 20 分钟。在基线和每个阶段后评估重复冲刺能力（5 × 6 秒冲刺，24 秒恢复）。在基线和 EX3 前后进行大腿肌肉活检，以确定全肌肉和纤维类型特异性糖原消耗。在运动后全肌肉糖原浓度相似（146 ± 20 和 122 ± 15）的情况下，全肌肉（p = 0.683）或纤维类型特定水平（p = 0.763–0.854）的肌糖原降解没有发现差异。分别在 CHO 和 PLA 中为 mmol·kg−1 dw）。 EX3 后，重复冲刺能力下降了约 9%，条件间没有差异 (p = 0.971)，感知用力等级也没有总体差异 (p = 0.550)。尽管整个运动过程中血糖浓度存在差异，CHO 和 PLA 的运动后水平分别达到 5.3 ± 0.2 和 4.1 ± 0.2 mmol·L−1 (p < 0.001)，同时血浆胰岛素水平高出五倍。 CHO（p< 0.001）。 总之，我们观察到，尽管血糖和胰岛素水平升高，但短期高强度间歇运动期间，碳水化合物摄入对净肌糖原分解或冲刺表现没有影响。因此，这些结果对碳水化合物补充策略在高强度间歇运动中的功效提出了质疑。