Despite concern about whether teenagers can safely participate in weight training, the National Strength and Conditioning Association recommends resistance training once kids are ready to participate in sports -- around the age of 7 or 8. The ability to build significant muscle mass, however, will be affected by whether or not the teenager has reached puberty.
Younger teenagers may not be able to increase their muscle mass due to lack of muscle-building hormones. However, according to TeensHealth, as male teenagers get older and reach puberty, they increase their testosterone levels, which is instrumental in building muscle. Female teenagers have significantly lower levels of testosterone and thus have muscle-building limitations.
When starting out, a teenager should lift weights two to three days per week on nonconsecutive days. Complete one to two sets of six to 15 repetitions of each exercise. Rest periods between sets should be one minute in length. Emphasis should first be on mastering the technique of each exercise before increasing workout volume or intensity. Complete exercises with little to no weight until the teen feel completely comfortable with the technique.
As a teenager becomes more experienced and has about two to three months of training completed, the training volume may be increased, which will result in a more significant increase in muscle mass. Lift three days per week, once again on nonconsecutive days, and perform two to three sets of eight to 12 repetitions of each exercise. Rest one to two minutes between sets. Use an appropriate amount of weight for each set so that the teen become fatigued toward the end of each set. Make adjustments to the weight as necessary. If the teen is unable to complete eight repetitions, lighten the weight. If the teen can complete 12 repetitions easily, increase the resistance.
A comprehensive weight-training program for teenagers looking to build muscle mass develops all of the major muscle groups, including the chest, back, shoulders, biceps, triceps, quadriceps, glutes, hamstrings and calves. Begin by using one exercise for each major muscle group. Once the teen has lifted for two to three months, incorporate a second exercise for each muscle group.
For the chest, complete chest presses and pushups. For the back, perform lat pulldowns and dumbbell rows. Target the shoulders with shoulder presses and dips. Biceps curls and hammer curls are effective at developing biceps, and lying triceps extensions and overhead triceps extensions target the triceps. Squats and lunges develop the glutes and quadriceps. Target the hamstrings using deadlifts and hamstring curls, and build the calf muscles with both standing and seated calf raises.