Department of Biosciences, University of Oslo, Oslo, Norway.
Faculty of Bioscience and Applied Chemistry, Hosei University, Tokyo, Japan.
Acta Physiol (Oxf). 2022 Nov;236(3):e13879. doi: 10.1111/apha.13879. Epub 2022 Sep 20.
Investigate whether juvenile exercise could induce a long-term muscle memory, boosting the effects of exercise in adults.
We devised a 5-week climbing exercise scheme with food reward administered to male juvenile rats (post-natal week 4-9). Subsequently, the animals were subjected to 10 weeks of detraining (week 9-19) without climbing and finally retraining during week 19-21.
The juvenile exercise increased fiber cross-sectional area (fCSA) by 21% (p = 0.0035), boosted nuclear accretion by 13% (p = 0.057), and reduced intraperitoneal fat content by 28% (p = 0.007) and body weight by 9% (p = 0.001). During detraining, the fCSA became similar in the animals that had been climbing compared to naive controls, but the elevated number of myonuclei induced by the climbing were maintained (15%, p = 0.033). When the naive rats were subjected to 2 weeks of adult exercise there was little effect on fCSA, while the previously trained rats displayed an increase of 19% (p = 0.0007). Similarly, when the rats were subjected to unilateral surgical overload in lieu of the adult climbing exercise, the increase in fCSA was 20% (p = 0.0039) in the climbing group, while there was no significant increase in naive rats when comparing to the contralateral leg.
This demonstrates that juvenile exercise can establish a muscle memory boosting the effects of adult exercise. The juvenile climbing exercise with food reward also led to leaner animals with lower body weight. These differences were to some extent maintained throughout the adult detraining period in spite of all animals being fed ad libitum, indicating a form of body weight memory.
研究青少年运动是否能产生长期的肌肉记忆，从而增强成年人运动的效果。
我们设计了一个为期 5 周的攀爬运动方案，并在雄性幼年大鼠（出生后第 4-9 周）中给予食物奖励。随后，动物在没有攀爬的情况下进行 10 周的停训（第 9-19 周），最后在第 19-21 周进行再训练。
青少年运动使纤维横截面积增加了 21%（p=0.0035），核积累增加了 13%（p=0.057），腹腔内脂肪含量减少了 28%（p=0.007），体重减少了 9%（p=0.001）。在停训期间，与未经攀爬训练的对照组相比，曾经进行过攀爬训练的动物的 fCSA 变得相似，但攀爬训练所诱导的核数量增加仍然存在（15%，p=0.033）。当未经训练的大鼠进行 2 周的成人运动时，对 fCSA 的影响很小，而之前接受过训练的大鼠的 fCSA 增加了 19%（p=0.0007）。同样，当大鼠进行单侧手术超负荷以代替成人攀爬运动时，攀爬组的 fCSA 增加了 20%（p=0.0039），而未经训练的大鼠与对侧肢体相比，没有明显的增加。
这表明青少年运动可以建立肌肉记忆，增强成年人运动的效果。有食物奖励的青少年攀爬运动还使动物变得更瘦，体重更低。这些差异在成年停训期间在一定程度上得到了维持，尽管所有动物都自由进食，这表明存在一种体重记忆。
