There are two possibilities. First, the muscles have adapted to your current training intensity. It is suggested to change the movements and weights. Second, overtraining, the muscles have not been fully rested and numb. It is suggested to adopt the training method every other day. In addition, we should pay attention to all aspects of fitness, including back, chest, shoulders, legs and arms. And coordinate development and scientific fitness! We must also maintain adequate nutritional supplements so that muscles can be fully trimmed and restored! I hope you stick to it!