Powerlessness: Because fitness consumes a lot of energy, muscles repeatedly do mechanical exercises, resulting in fatigue, so they will feel powerless after exercise;

Sour swelling: Because the physical exercise is much larger than usual, muscle cells have no oxygen to breathe and produce lactic acid. After strenuous exercise, lactic acid is produced in large quantities, and the decomposition speed can't keep up, so it is sour when accumulated.

You need to supplement protein.