You will need: 

Sport knee socks 
Sports shirt
Belt with a huge belt buckle (optional)
Athletic long baggie shorts 
Tennis Shoes
Bathrobe to drap down his back or some type of a cape 

Instructions

A.  Dress your child in his athletic shorts and shirt. 

B.  Put his sports knee socks on and tennis shoes

C.  Put the cape on to drape down his back or use a bath robe or a homemade cape 

D. Place the belt with the big belt buckle around his waist (optional)