ankle pain

My 13 year old son has been training 3-4 days a week in martial arts for more than 7 years without injury or complaints of more than minor muscle stiffness after heavy workouts.
He just started track and, after only two training sessions, he complains of severe pain and stiffness in both ankles near the front of his feet.
He says that he does not have pain with any rotation, extension or retraction but has pain and stiffness with weight bearing and walking.
He has a new pair of good, NIKE running shoes that fit well and he reports they are very comfortable to run in.
He runs with a straight back and it looks like a fairly stiff posture and is a very fast sprinter, running mostly on his toes or the balls of his feet.
Any observations or suggestions would be appreciated.
Thanks.