Exercising abdominal core muscles is one of the important ways of abdominal shaping and exercise. However, abdominal weakness after exercise may be due to the following reasons:

1. Muscle fatigue after exercise: During abdominal exercise, muscles will be greatly stimulated, leading to muscle fatigue and relaxation. This may cause the abdominal muscles to temporarily soften after exercise.

2. Muscle growth: In the process of fitness, during the growth and strengthening of abdominal muscles, some muscles may be damaged and need to be recovered through rest and nutritional supplement. During this process, muscles may become slack, but this is a normal recovery process.

3. Diet and water intake: Unhealthy eating habits or insufficient water intake may lead to body inflammation and muscle relaxation. Maintaining healthy eating habits and adequate water intake will help reduce this situation.

4. Exercise intensity and frequency: If the intensity and frequency of exercise are too high, it may lead to muscle fatigue and overuse, and then lead to muscle relaxation. Adjusting the intensity and frequency of exercise properly and giving the body enough time to recover and adapt will help to reduce this situation.

In a word, abdominal softening after fitness may be the result of many factors. In the process of fitness, properly adjusting the intensity and frequency of exercise, maintaining healthy eating habits, adequate water intake and adequate rest and recovery will help reduce the occurrence of abdominal malacia, promote the overall health of the body and improve the shaping effect.