My son runs very very slow (no offense but he runs like an 80 yr old man). He is 50 inches/52 lbs and is 6 yrs old. He is very active (plays Karate, Ice hockey, tee-ball). Is this something he will grow out of? How can i tell if there is something biomechanically wrong? he has been ice skating since 3 yrs old, could this have impacted his gait?