SON FLAPPING ARMS WHEN EXCITED WHEN WATCHING FOOTBALL

I have a seven year old son who seems to flap his hands and stiffen up when he is excited watching football ...when we catch him doing it he stops automaticly so he is able to control them..
Sometimes he does it in a pace up and down pretending he is playing football..he only does this at home and never in public.

When I asked him what he is doing he said it calms him down..

In terms of motor skills he is fine , he has no speech problems , he s very popular at school and is average in his class in terms of ability ...

However when he was born he had a traumatic birth which resulted in convulsions a few hours after the birth ..he had them again on day 2 but then never again.......

after constantly going to hospital for the first yea of his life were told he was fine so obviously with the hand flapping thats happening every so ofet I am anxious in what to do?

[LivingInHope]

I'm not a doctor  and cannot diagnose, but might I suggest you go to a psychiatrist to have him tested, because it sounds to me like he may be suffering from obsessive compulsive disorder (OCD).  They say it is key that this be caught as early as possible for best chance with treatment.