Great question. Resistance training, also called strength training, is an excellent way for young athletes to improve sports performance while enhancing body composition, developing good posture, reducing risk of injury, and building strong bones; at 14, your son is old enough to safely participate in this activity with the proper level of instruction and supervision.
For safety, kids and teens who wish to undergo strength training need to be medically cleared to participate; and they need to follow a structured training program under the direct supervision of a certified fitness professional. Your best bet is to look for a certified trainer with experience and certification in working with youth, preferably high school athletes. Take your time and ask plenty of questions in selecting the right trainer; not all certified trainers are equally qualified.
Generally, adult guidelines for strength training are appropriate for teens. A trainer will customize these guidelines for your son’s needs and goals:
• Train each major muscle group 2-3 days/week.
• 2-4 sets of 8-12 repetitions
• Rest in between sets for 1-2 minutes or more
• Allow at least 48 hours in between training sessions
• Progress gradually by increasing resistance by about 5% when the recommended number of sets and reps are achieved with proper form during 2 consecutive training sessions.
Be sure to facilitate open communication between the certified personal trainer you select and your son’s coach. To develop a safe and effective program, the trainer will need detailed information about your son’s sports-specific and off-season training.