University of Birmingham.
Maastricht University Medical Centre.
Int J Sport Nutr Exerc Metab. 2021 May 1;31(3):209-216. doi: 10.1123/ijsnem.2020-0274. Epub 2021 Feb 17.
The impact of resistance exercise frequency on muscle protein synthesis rates remains unknown. The aim of this study was to compare daily myofibrillar protein synthesis rates over a 7-day period of low-frequency (LF) versus high-frequency (HF) resistance exercise training. Nine young men (21 ± 2 years) completed a 7-day period of habitual physical activity (BASAL). This was followed by a 7-day exercise period of volume-matched, LF (10 × 10 repetitions at 70% one-repetition maximum, once per week) or HF (2 × 10 repetitions at ∼70% one-repetition maximum, five times per week) resistance exercise training. The participants had one leg randomly allocated to LF and the other to HF. Skeletal muscle biopsies and daily saliva samples were collected to determine myofibrillar protein synthesis rates using 2H2O, with intracellular signaling determined using Western blotting. The myofibrillar protein synthesis rates did not differ between the LF (1.46 ± 0.26%/day) and HF (1.48 ± 0.33%/day) conditions over the 7-day exercise training period (p > .05). There were no significant differences between the LF and HF conditions over the first 2 days (1.45 ± 0.41%/day vs. 1.25 ± 0.46%/day) or last 5 days (1.47 ± 0.30%/day vs. 1.50 ± 0.41%/day) of the exercise training period (p > .05). Daily myofibrillar protein synthesis rates were not different from BASAL at any time point during LF or HF (p > .05). The phosphorylation status and total protein content of selected proteins implicated in skeletal muscle ribosomal biogenesis were not different between conditions (p > .05). Under the conditions of the present study, resistance exercise training frequency did not modulate daily myofibrillar protein synthesis rates in young men.
抗阻运动频率对肌肉蛋白质合成速率的影响尚不清楚。本研究旨在比较低频（LF）与高频（HF）抗阻运动训练 7 天期间每日肌原纤维蛋白合成速率。9 名年轻男性（21 ± 2 岁）完成了 7 天的习惯性体力活动（基础期，BASAL）。随后进行了为期 7 天的运动期，运动方式为等容量的 LF（10 次×10 次，70%一次重复最大重量，每周 1 次）或 HF（2 次×10 次，约 70%一次重复最大重量，每周 5 次）抗阻运动训练。参与者的一条腿随机分配到 LF，另一条腿分配到 HF。采集骨骼肌活检和每日唾液样本，使用 2H2O 测定肌原纤维蛋白合成速率，使用 Western 印迹法测定细胞内信号。在 7 天的运动训练期间，LF（1.46 ± 0.26%/天）和 HF（1.48 ± 0.33%/天）条件下的肌原纤维蛋白合成速率没有差异（p >.05）。在运动训练的前 2 天（1.45 ± 0.41%/天 vs. 1.25 ± 0.46%/天）或最后 5 天（1.47 ± 0.30%/天 vs. 1.50 ± 0.41%/天），LF 和 HF 条件之间没有显著差异（p >.05）。在 LF 或 HF 期间，肌原纤维蛋白合成速率在任何时间点均与基础期（BASAL）没有差异（p >.05）。参与骨骼肌核糖体生物发生的选定蛋白质的磷酸化状态和总蛋白含量在条件之间没有差异（p >.05）。在本研究条件下，抗阻运动训练频率不会调节年轻男性的每日肌原纤维蛋白合成速率。
