My son is a 14 year old pitcher, he is 5’7 115 pounds and his core lifts are: Bench- 130 Squat-180 Deadlift-170 to 200. He sits at around 70mph with what his coaches have described as “awful mechanics” I am currently working on improving his mechanics but my question is this: Should he gain weight to add velocity and if so what would be a reasonable expectation for velocity improvement?
Gaining muscle does not directly indicate a gain in velocity. Arm strength and arm speed must be balanced in order to maximize velo. Muscle added at the expense of mobility and flexibility can actually cause a decrease in velo. Finding a proper balance and a coach that knows the science behind velocity is key to staying healthy and reaching your maximum potential.
NPAcaseyb is absolutely right!! IMO: I think you’re wasting time trying to gain weight, velocity, muscle, etc… if he has “awful mechanics”. Best to fix this before anything else. If you don’t have a good local facility/coach…look into Driveline baseball and get him on a monthly plan with an online coach. This way he will have a program build just for him, based upon his deficiencies and needs.
I agree with other commenters on improving your son’s mechanics. In addition to boosting velocity, good mechanics will help him avoid injury and develop command.
That said, age 14 is a great time to start serious strength and conditioning. Everything in the game of baseball gets easier with more power and speed.
If you can find a pitching coach who will work with your son on both mechanics and strength & conditioning, that would be ideal. There are also plenty of good strength & conditioning programs you can buy on Amazon or access on the internet for a fee.
I wouldn’t focus too much on weight. If your son is following a good strength & conditioning program and getting plenty of nutrition, weight should come naturally. Just don’t stint on the calories and protein. You’d be surprised how much young athletes who are pushing hard in their training need. When my son was a junior, a college recruiter advised him to increase his calorie intake to 4600 daily to support muscle growth. Doing that helped enormously in terms of both size and strength.