The scope of fitness is very wide, so if you exercise correctly and scientifically, there is no bad influence, but it will promote development, promote physical health and form a good habit of exercise from an early age.

I guess you want to know whether weight training, abdominal muscle exercise and other muscle exercises will affect growth and development. The answer is that it will not hinder, but will promote growth and development. Even if you practice weightlifting, it will also promote the growth of your height.

However, it is not recommended for minors to carry out weight-bearing exercise without professional guidance, because the bones of minors are still developing. Although resistance training can promote bone growth, because minors' bones are soft, using heavy weight without professional guidance can easily lead to bone deformation or muscle imbalance, which will lead to posture problems. Minors are in the period of growth and development, so random self-weight exercise can achieve good results, so you can actively carry out some self-weight exercises, such as self-weight squats, push-ups, pull-ups, etc., which can bring good benefits to growth and development.