5yr odl won't participate in group activities

Over the past few years I have signed up my now 5yr old for a range of group activities such as gymnastics, music, piano, skiing, soccer, swimming and art. he usually does well in the first class and then he starts misbehaving: he'll disrupt the activities by not following instructions or pretend he doesn't hear or even physically try to leave - making it really challenging for his teachers to keep the class going. Afterwards he is often completely unaware of how difficult he has been and happily asks me " Did I do really well today?". His behavior is frustrating to me as well as to other participants and , of course, the leaders/teachers. In school, he does really well except in activities such as listening to a peer speak during circle time or participating in discussions himself. He often says that he gets too tired to pay attention.  I have been thinking that he might be too young for instruction but I see 3 yr olds do better than he so I am beginning to worry . Has anyone else had a similar experience? Thanks.

[kg17]

Many young boys demonstrate a high energy level and very short attention span.  At the extreme end (about 5%) these boys might truly have ADHD.  In general, the behavior you describe is normal for a 5-year-old boy and he might not yet be ready for group instruction.  You would likely have better success with an instructor that can work with him one-on-one and at his pace.  Or, there's nothing wrong with pulling him from structured activities and letting him do free play.  I never had one extra-curricular activity until high school, and somehow I did pretty well in life - obtained a Ph.D., got married, have three kids.

[Mymlan]

Thanks so much for your answer. I agree with all your suggestions and , in fact, have now heard similar stories from other parents. I feel much better!