Weight Training for Young Adults

Jay H. Williams, Ph.D.


March 2008

Coaches, athletes and parents often ask about the appropriateness of weight training for young athletes.  Is it safe and effective?  This is one area of youth sports where there seems to be a number of myths and considerable misinformation.  The old story holds that weight lifting will stunt a child’s growth.  This myth seems to have been arisen from a 1964 study showing that Japanese children who performed heavy labor tended to be shorter in stature than those who did not.   However, the study did not examine other factors such as nutrition which may have affected growth.  Also heavy labor is much different than a supervised weight training session.

Today there is little reason to suspect that weight lifting as part of comprehensive training program would adversely affect a child’s growth.  As it turns out, the overwhelming majority of evidence indicates that weight lifting in young athletes can be very safe and is very effective in promoting strength, enhancing performance and reducing the risk of injury.


The first question surrounding youth weight training is, “is it safe for the young athlete?”  The answer to that question is a resounding yes, with one caveat.  Research studies that examined the effects of weight training on children and adolescents report only the rare occurrence of injuries.  When injuries do occur, they are usually muscle strain or lower back pain and are often resolved within 5 days.  The most common cause is poor technique (more on this later).  Reported injury rates for youth strength training are small, on the order of less than 1 per 1000 participant hours.  This is roughly 80% lower than rates reported for participation in youth soccer and other sports, 4-5 per 1000 hours of play.  As for long-term or chronic injuries, radiographic bone scans and plasma analyses of bone, muscle and connective tissue changes show no indications of damage to epiphyses (growth plates), articular cartilage  (joint surfaces), tendon, ligament or muscle.  Particularly important is that there is no evidence to suggest any adverse effects of weight training on musculoskeletal growth, development, flexibility or performance of young athletes.

The important caveat to consider is proper supervision and adequate instruction.  The majority of injuries that occur do so as a result of poor technique.  Either proper technique was never learned or lack of supervision lead to incorrect lifting form.  Research indicates that most injuries can be avoided using programs that incorporate competent and consistent feedback regarding proper lifting technique.  It is also critically important to consider the emotional maturity of the athlete when initiating a weight training program.  Children, who are unable to follow directions, accept supervision or focus on the activity at hand should not participate in a weight training program.

Overall, weight training for young athletes can be a safe activity in that the risk injury or long term complications is very small.  As such, a number of sports medicine organizations have stated that properly supervised weight training programs with appropriate technical instruction are both safe and effective for children and adolescents.

Organizations that promote youth weight training

  • American Academy of Family Physicians
  • American Academic of Orthopedic Surgeons
  • American College of Sports Medicine
  • American Medical Society for Sports Medicine
  • American Orthopedic Society for Sports Medicine
  • American Osteopathic Academy of Sports Medicine
  • American Academy of Pediatrics
  • British Association of Exercise and Sports Sciences
  • National Strength and Conditioning Association
  • President’s Council on Physical Fitness and Sport


The second question asked is, “is weight training effective?”  Research indicates that in children as young as age 6 to adolescents as old as age 18, weight training improves both muscular strength and physical performance.  Training programs of 8-12 weeks typically elicit strength gains of 30-50%.  In a recent study on young soccer players (12-15 years), weight lifting added to a soccer training program resulted in significant increases in both upper and lower body strength by more than 50%, sprint and shuttle run speed by 3-5% and vertical jump height by 23%.  These results indicate that weight training incorporated as a part of a comprehensive soccer training program can improve strength, agility and speed.

For young athletes, strength gains are mostly the result of neuromuscular adaptations with little or no muscle growth.  Following weight training, athletes show increased ability of activate muscle fibers and enhanced reflex responses.  In older adolescent boys, the strength gains occur along with increases in muscle mass and neuromuscular adaptations.  At these ages, increased levels of androgens (e.g. testosterone) allow for muscle growth and adaptation.  In adolescent girls, some hypertrophy occurs but much of the strength gains are due to neuromuscular changes. Despite the specific mechanisms, it is cleat that weight training in youngathletes increases strength and improves athletic performance.


Aside from increasing strength and enhancing performance, there are a multitude of additional benefits to weight training.  Bone health is improved through increased bone mineral density.  Weight bearing activities such as strength training, mechanically stress the bone which, in turn, stimulates osteogenic activity (bone production).  This stimulus likely enhances the normal growth-related increased in bone mass and increases the strength of the developing bone.  As noted above, this occurs without detrimental effects on growth plates. Resistance exercises also seem to lessen the risk of injury during competition.  Several studies show reduced injury rates in adolescent athletes who participate in conditioning programs that include weight training.  It appears that increased muscular strength, increased strength of connective tissues (tendon and ligament) as well as enhanced neuromuscular reflexes all act to stabilize various joints that are at risk (e.g. ankle and knee).  This may be particularly important for females where the risk of anterior cruciate ligament injury may be reduced through resistance exercises.


Athletes can use a combination of body weight exercises, machines and free weights.  Inexperienced lifters should focus on using body weight exercises and machines. These exercises are very safe and can help the athlete develop proper technique along with building strength and balance needed to perform the more complex free weight lifts. These exercises also allow the athlete to get comfortable with the facility and learn proper etiquette.

As the athlete gains strength and experience, free weights can be incorporated using both dumbbells and barbells. Free weights utilize the full range of motion and enhance core and joint stabilization by activating a number of “accessory” muscles.  However, the use of free weights without proper technique and adequate supervision can raise the risk of injury. For younger athletes and those beginning a program, it is preferable to use sets requiring 12-15 repetitions.  This generally limits the amount of weight that can be lifted to 70-80% of their one-repetition maximum and allows the athlete to comfortably complete the lifts using proper technique.  Studies also show that for children, strength gains are maximized using the low weight-high repetition approach compared to a high weight-low repetition program.


The most important aspect of a weight training program for young athletes is having an experienced and competent trainer to provide both instruction and supervision.  This will insure that the benefits of the program are maximized and the risk of injury is minimized.  Trainers should have certification through a well-respected, professional organization such as the National Strength and Conditioning Association or the American College of Sports Medicine. The trainer’s role is three-fold.  First, they should instruct athletes on proper use of equipment and the technical execution of each exercise.  Second, trainers should supervise each exercise and provide consistent feedback to insure that the exercise is done technically correct.  If technique degrades, the training load should be reduced until the athlete can execute the lift properly.  Third, they should constantly monitor each athlete and be prepared adjust the exercises in order to maximize benefits and minimize injuries.  Most important, training should be reduced and stopped if the athlete experiences any sort of muscle or joint pain or discomfort.


While it is clear that weight training in young athletes can be both safe and effective, there are some broad general guidelines to be followed.  These guidelines serve to guard against injury while maximizing the benefits of the training program.  The athlete must be emotionally mature He/She must be able to follow instructions and take supervision

Training Program

  • Train 2-3 days per week
  • Use 7-10 exercises focused on the major muscle groups
  • For each exercise, perform 1-3 sets of 10-15 repetitions
  • Use moderate weight and emphasize proper technique
  • Types of Exercises
  • Exercises may incorporate a combination of body weight, machine and free weight exercises
  • Use body weight and machine exercises to build strength and technique
  • Overhead lifts using free weights should be avoided


  • Trainers should be adults, experienced and certified through a respected professional organization.
  • Athletes should taught correct technique and be supervised at all times.
  • Training load should be stopped at the first sign of muscle or joint discomfort


Based on the available evidence, it is clear that weight training for young athletes is safe and effective.  Previous concerns over stunted growth and damaged growth plates have been exaggerated and are unwarranted.  Over the past 20 years, many well designed research studies show that children and adolescents can enhance strength through weight lifting without encountering any long term adverse affects.  However, precaution should be taken.

Athletes must be emotionally mature enough to follow instructions and trainers must provide proper instruction and supervision of the athletes.  The bottom line is that with proper instruction and supervision, weight training can be a safe and beneficial part of a comprehensive soccer training program.


The original PDF version of this article can be found at http://filebox.vt.edu/users/jhwms/SOS/WeightTraining.pdf

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