Help with running form

My 12 yo son is an outside midfielder (l & r). His position necessitates frequent short burst runs down the field. He's quick and has endurance, but his form stinks - think Phoebe from Friends. I think he would be faster, more effective and get less winded if his form was better and he wasn't expending so much energy flailing his arms around. We've done speed/agility classes in the past, but they didn't address this specific issue. Any recommendations on classes/programs in which we could enroll him to help with this? We're in Keller, so we need something on the west side. We plan to have him run track in the fall (7th grade) and assume that will help, but were looking for something we could do to help him over the summer.

https://youtu.be/2_t7YTFFAkY

I like this guys videos.

Michael Johnson Performance Center. Sorry this isn't close to you but it addresses your need specifically.

http://michaeljohnsonperformance.com/