1. It may be that the life circle has influenced his health concept, and he feels that people around him are very strong. Fitness can improve his temperament and enhance his self-confidence.

2. Maybe he met the opposite sex he liked and hoped to adjust his body shape through fitness in order to be liked.

Perhaps he began to pay attention to his health and realized that only by having a good body can he support his family responsibilities and realize his personal value.

Whatever the reason, it is a positive attitude towards life for boys to suddenly start fitness, which deserves encouragement and support.