Department of Physical Therapy, School of Health Sciences, Ariel University, Ariel, Israel.
Acta Physiol (Oxf). 2018 May;223(1):e13027. doi: 10.1111/apha.13027. Epub 2018 Jan 24.
Elevated glycogen content in muscle delays fatigue during exercise. We examined if increasing muscle temperature during recovery from exercise affects glycogen synthesis and muscle performance during a subsequent bout of exercise.
Isolated mouse extensor digitorum longus muscles were stimulated electrically to perform repeated tetanic contractions until force decreased to 40% of initial at 25°C. Thereafter, muscles recovered for 120 minutes at 25°C (control), 120 minutes at 35°C or 60 minutes at 35°C followed by 60 minutes at 25°C. After recovery, muscles were again stimulated to fatigue at 25°C.
In the control group, the number of contractions in the second run was slightly less than during the first run (92 ± 5%). Following recovery for 120 minutes at 35°C, the number of contractions was similar to the first run (98 ± 6%). Allowing recovery for 120 minutes at 35°C in the presence of the antioxidant N-acetylcysteine also did not alter the number of contractions in the second run (98 ± 3%). However, recovery for 60 minutes at 35°C followed by 60 minutes at 25°C resulted in an increase in the number of contractions during the second run (110 ± 2%, P < .001). Incorporation of [ C]glucose into glycogen (glycogen synthesis) during recovery was 1.7-fold higher at 35°C vs 25°C (1.44 ± 0.08 μmol (30 min) (g wet muscle) vs 0.84 ± 0.04; P < .001).
These data demonstrate that, under the conditions studied, elevating muscle temperature for 60 minutes following a bout of repeated contractions delays muscle fatigue during a subsequent bout of repeated contractions and this is associated with enhanced glycogen synthesis in isolated muscle.
肌肉中糖原含量的升高会延迟运动时的疲劳。我们研究了在运动恢复过程中升高肌肉温度是否会影响随后一次运动时的糖原合成和肌肉性能。
分离的小鼠趾长伸肌通过电刺激进行重复的强直收缩，直到在 25°C 时力降至初始值的 40%。此后，肌肉在 25°C（对照组）下恢复 120 分钟，在 35°C 下恢复 120 分钟，或在 35°C 下恢复 60 分钟，然后在 25°C 下恢复 60 分钟。恢复后，肌肉再次在 25°C 下刺激至疲劳。
在对照组中，第二次运行的收缩次数略少于第一次运行（92±5%）。在 35°C 下恢复 120 分钟后，收缩次数与第一次运行相似（98±6%）。在第二次运行中，让肌肉在 35°C 下恢复 120 分钟并存在抗氧化剂 N-乙酰半胱氨酸也不会改变收缩次数（98±3%）。然而，在 35°C 下恢复 60 分钟，然后在 25°C 下恢复 60 分钟，导致第二次运行中的收缩次数增加（110±2%，P<0.001）。在恢复期间，[C]葡萄糖掺入糖原（糖原合成）的速度在 35°C 时比 25°C 时高 1.7 倍（1.44±0.08 μmol（30 min）（g 湿肌肉）比 0.84±0.04；P<0.001）。
这些数据表明，在所研究的条件下，在一次重复收缩后，升高肌肉温度 60 分钟可延迟随后一次重复收缩时的肌肉疲劳，这与分离肌肉中糖原合成的增强有关。
