Natural fitness. Natural athletes need training, which means maximizing muscle fiber recruitment, muscle fiber fatigue and increasing mtor to activate protein synthesis. If you don't train or the training frequency is low, your body will maintain internal stability and your muscles will not increase or even decrease. Scientific and technological athletes are in the state of protein synthesis 24 hours a day, and they can gain muscle without training or with low training frequency. Dayu Fitness is the account of a fitness blogger in Tik Tok. The account profile says: Seven years of natural fitness, traces of natural fitness can also be seen in some videos updated in the account, as well as some daily exercise and diet, not scientific fitness.