I received a good question by email.

my son has been clocked as high as 91 mph but sometimes he sits on 84 and 87 mph is there something he can do to sit at 91 and up?

91mph is what he is topping out at. This is usually when he is his healthiest and he has better mechanics. His velocity range is around 84-87 as you stated. For him to gain more velocity he must learn better mechanics, a training program that trains fast twitch muscles especially in the core and legs and a diet that helps speed his recovery and promote muscle development.

I recommend you read my article 10 Legitimate Tips to Pitching Velocity. This will help get him on the path to more velocity.

It would also help to know his current training regime, diet and throwing program.

I would also recommend pitching analysis to help better his mechanics.

This site offers a lot of FREE information to get him throwing harder and training smarter.