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Youth Strength

For decades, preadolescents have been prohibited from performing strength exercise because we were led to believe that resistance training would damage their bone growth plates and retard their musculoskeletal development. Fortunately, nothing could be further from the truth. In fact, there has never been a case of bone growth plate damage due to strength exercise reported in the United States. Furthermore, progressive resistance training is the best and, in our increasingly sedentary society, perhaps the only way to enhance musculoskeletal development in boys and girls.

We have also heard that pre-teens cannot benefit from strength training because they do not have enough testosterone (male sex hormone associated with muscularity) to make significant gains in muscle strength. This argument makes no more sense than saying that women can’t increase muscle strength because they have too little testosterone. Obviously, both women and children can experience major improvements in muscle strength from regular participation in resistance training programs. In a classic study by Faigenbaum and associates, 10 year old boys and girls made overall strength gains of 74 percent after just two months of twice-a-week training (see Table 5.1). Although the non-training control subjects increased strength by 13 percent through normal growth and development, the exercisers made significantly greater improvement.

Table 5.1 Changes in muscle strength for exercisers and controls after eight week training period (23 subjects, mean age 10 years).
Exercise Group (n=14) Control Group (n=9)
10 RM Strength (in Kilograms) Pre Post % Change Pre Post % Change
Leg Extension 12.9 21.2 64.5* 12.1 13.8 14.1
Leg Curl 10.4 18.5 77.6* 12.0 13.6 13.2
Chest Press 15.2 25.0 64.1* 13.4 15.0 12.5
Overhead Press 7.5 14.1 87.0* 7.8 8.8 13.1
Biceps Curl 4.7 8.3 78.1* 4.8 5.3 12.2
Mean % Change 74.3 13.0

We were then told that training-related strength gains were temporary, and that shortly following the exercise program the children who worked out would be no stronger than their untrained peers. A second landmark study by Faigenbaum and associates proved that this assumption was untrue for upper body muscles. After two months of twice-a-week training, the 10 year old boys and girls experienced a 41 percent increase in chest press strength. Following two additional months of no strength training the exercise group regressed 19 percent, but was still significantly stronger than the control group in chest press performance (see Figure 5.1).

Figure 5.1.Changes in chest press strength for exercise and control subjects over 8-week training and 8-week detraining periods (24 subjects, mean age 10 years)

Because strength gains have a neuromuscular component, it has been assumed that all strength training improvements in children are due to motor learning rather than muscle development. However, a public school strength training study conducted by Westcott and associates showed otherwise.

As presented in Table 5.2, the fifth grade boys and girls who strength trained twice-a-week for eight weeks added significantly more lean (muscle) weight than a matched control group that did not perform resistance exercise. This result indicated that the strength exercise produced muscle development beyond that associated with normal growth in children.

Table 5.2 Changes in body composition for exercisers and controls after eight-week training period (42 subjects, mean age 11 years).
Group % Fat Change Lean Weight Change (lbs) Fat Weight Change (lbs)
Exercise -2.7* +2.5* -3.0*
Control -1.9* +1.5* -1.4*
* Significant Change (p<0.01).

Finally, critics have complained that strength training is unnatural and preadolescents don’t like doing it. Instead, they argue that young people should exercise with their body weight, doing pull ups, push ups and sit ups.

This has not been our experience at the YMCA or in the school setting. Since Dr. Faigenbaum added classes for repeat participants, we have had many boys and girls sign up for over two years of successive strength training programs. After they outgrow the child-sized equipment, most join a similar program in our YMCA fitness center and continue to strength train on the Nautilus machines.

Similarly, the fifth graders who did strength exercise at school made such impressive physical improvements that their classmates requested and received an expanded program for all students the following semester. Furthermore, 100 percent of the strength program participants reported that it had been a positive experience.

So let’s summarize what we now know about youth strength training.

  1. Strength training does not cause damage to bone growth plates in children.
  2. Preadolescent boys and girls can significantly increase muscle strength through progressive resistance exercise.
  3. Children who complete an eight-week resistance training program have significantly greater upper body strength than their peers after an additional eight weeks of no resistance exericse.
  4. Preadolescent boys and girls can significantly increase lean (muscle) weight through progressive resistance exercise.
  5. Children typically express satisfaction with both the process and product of supervised strength exercise.

Bodyweight vs. Progressive Resistance Exercise

Training with bodyweight exercises can be productive if your body is the right weight for your muscular ability. Unfortunately, for most adults and children, our bodyweight is too heavy to permit safe and successful strength development. For example, relatively few adults or youth can perform even one chin up, making this bodyweight exercise unsuitable for training purposes.

Although properly performed pushups present a similar problem for many boys and girls, let’s assume that Johnny can complete 10 good push ups. While this represents an appropriate training load, he is unable to progressively increase the exercise resistance. Yes, he can perform more repetitions with his bodyweight, but adding repetitions is not nearly as effective for building muscle strength as gradually increasing the training resistance.

As for safety, it is far less risky for a child to perform 10 pulldowns with half his/her bodyweight (e.g., 40-pound weightstack resistance), than to struggle unsuccessfully with a single pull up (e.g., 80-pound bodyweight resistance). The major advantage of weight training over bodyweight training is that the resistance can be adjusted to the child’s present muscular ability and progressively increased as strength improves.

With this in mind, let’s consider established strength training guidelines for both adults and children.

Strength Training Guidelines

In 1987, the YMCA of the USA became the first national association to publish guidelines for adult strength training. A few years later, both the American College of Sports Medicine and the American Council on Exercise issued their recommendations for adult strength training. Fortunately, all three of these fitness organizations presented essentially the same training principles for safe and productive strength exercise. In general, the key training factors are as follows:

These are excellent suggestions for safe, sensible, and successful strength training experiences that can be applied to youth exercisers as well as adults and seniors. However, even before these recommendations were published, the American Orthopedic Society for Sports Medicine, the American Academy of Pediatrics, the American College of Sports Medicine, the Society of Pediatric Orthopedics, the National Athletic Trainers Association, the U.S. Olympic Committee, the National Strength and Conditioning Association, and the President’s Council on Physical Fitness and Sports developed a collaborative position paper on strength training for preadolescent boys and girls. First presented in 1985 and published in 1988, these youth strength training guidelines provide the following directives.


  1. Strength training equipment should be of appropriate design to accommodate the size and degree of maturity of the prepubescent.
  2. It should be cost-effective.
  3. It should be safe, free of defects, and inspected frequently.
  4. It should be located in an uncrowded area free of obstructions with adequate lighting and ventilation.

Program Considerations

  1. A pre-participation physical exam is mandatory.
  2. The child must have the emotional maturity to accept coaching and instruction.
  3. There must be adequate supervision by coaches who are knowledgeable about strength training and the special problems of prepubescents.
  4. Strength training should be a part of an overall comprehensive program designed to increase motor skills and level of fitness.
  5. Strength training should be preceded by a warm-up period and followed by a cool-down.
  6. Emphasis should be on dynamic concentric contractions.
  7. All exercises should be carried through a full range of motion.
  8. Competition is prohibited.
  9. No maximum lift should ever be attempted.

Prescribed Program

  1. Training is recommended two or three times a week for 20 to 30 minute periods.
  2. No resistance should be applied until proper form is demonstrated. Six to 15 repetitions equal one set; one to three sets per exercise should be done.
  3. Weight or resistance is increased in one- to three-pound increments after the prepubescent does 15 repetitions in good form.

These recommendations are just as relevant today as they were in 1985, but research studies conducted during the 1990s have enabled us to make a few refinements that enhance both the training efficiency and exercise effectiveness. For example, we recently compared preadolescent strength gains achieved from fewer repetitions (six to eight) with heavier weightloads and those attained from more repetitions (13 to 15) with lighter weightloads. As presented in Table 5.3, the children who performed 13 to 15 repetitions gained significantly more muscle strength and endurance than those who performed six to eight repetitions over an eight-week training period. Unlike adults, our findings indicate that preadolescent boys and girls may respond better to training with higher repetitions and lower weightloads than to training with lower repetitions and higher weightloads.

Table 5.3 Effects of youth strength training with higher repetitions and lower weightloads vs. lower repetitions and higher weightloads (N= 43).
Variable Control Group
(6-8 Reps)
Low Rep Group
(6-8 Reps0
High Rep Group
(13-15 Reps)
Leg Extension Strength +13.6 % +31.0 % +40.9%
Chest Press Strength +4.2 % +5.3 % +16.3%
Leg Extension Endurance +3.7 reps +8.7 reps +13.1 reps
Chest Press Endurance +1.7 reps +3.1 reps +5.2 reps

Our studies also suggest that pre-adolescents who perform one high-effort set of each exercise experience about the same strength gains as those who perform three high-effort sets of each exercise. In other words, a single set of resistance exercise is an efficient and effective means for increasing muscle strength in young boys and girls. More sets may be performed if desired, but we have not observed much difference in strength development between single and multiple-set training programs in pre-adolescents.

Although young people are prone to do things quickly, we insist on exercise control achieved through relatively slow lifting and lowering movements. We generally require six seconds for each repetition, with two seconds for lifting actions and four seconds for lowering actions. We believe that controlled movement speeds maximize strength development and minimize injury risk. Because fast movement speeds involve momentum, they may decrease the exercise effect and increase the risk of injury.

Our youth strength training studies have shown similar results from two or three exercise sessions per week. On the one hand, most boys and girls like the strength training program and are willing to exercise three days per week. On the other hand, two weekly workouts may make more sense for young people who are involved in additional physical activities such as dance, gymnastics, swimming, tennis, or team sports.

We recently completed a 10 week strength training study with female figure skaters between five and 13 years of age. Because these athletes skated several days each week, they performed strength exercises just one or two days per week. The younger girls did 10 exercises on child-sized machines, and the older girls completed 10 Nautilus exercises each session. These were, in order, the leg press, incline press, compound row, bench press, shoulder press, rotary torso, low back, abdominal, weight assisted chin ups and weight assisted bar dips.

Even with the low training frequency, the program participants experienced excellent results. As shown in Table 5.4, the young skaters increased their lower body strength by 99 percent, their upper body strength by 36 percent, their hamstring flexibility by five percent, their long jump by five percent, and their vertical jump by 13 percent. This latter improvement was most relevant to their skating performance, as the coaches reported much better jumping ability on the ice. Perhaps most important, all of the girls had positive attitudes toward strength training and committed to continue the exercise program.

Table 5.4 Changes in muscle strength, joint flexibility and performance power for female figure skaters (16 subjects, mean age 10 years).
Parameter Pre Training Post Training Change
Leg Press 47.4 lbs 94.5 lbs. 47.1 lbs.
Bench Press 31.7 lbs. 43.2 lbs. 11.5 lbs.
Sit/Reach 19.8 in. 20.9 in. +1.1 in.
Long Jump 55.2 in. 57.8 in. +2.6 in.
Vertical Jump 10.2 in 11.5 in. +1.3 in.

The strength workout should ideally include all of the major muscle groups, which may be accomplished by different exercise selections. Table 5.5 presents basic free-weight exercises and machine exercises available on youth-sized equipment that address the major muscle groups. If youth-sized equipment is not available, most children can safely perform strength exercises on standard Nautilus machines that require linear rather than rotary movements. That is, they can do pushing and pulling exercises such as leg presses, bench presses, compound rows, and overhead presses. However, only those youth who are large enough to align their joints with the machine axes of rotation should perform rotary exercises such as leg extensions, leg curls, chest crosses, pullovers and lateral raises. Table 5.6 provides our recommended Nautilus machine linear exercises for boys and girls.

Table 5.5 Standard free-weight and child-sized machine exercises for the major muscle groups.
Front Thigh
Dumbbell Squat
Dumbbell Lunge
Dumbbell Step-Up
Leg Extension
Leg Press
Rear Thigh
Dumbbell Squat
Dumbbell Lunge
Dumbbell Step Up
Leg Curl
Leg Press
Hip Extension
Inner Thigh
(Hip Adductors)
Ankle Weight Adduction Hip Adduction
Outer Thigh
(Hip Abductors)
Ankle Weight Abduction Hip Abduction
Lower Leg
Dumbbell Heel Raise Toe Press
(Pectoralis Major)
Dumbbell Bench Press Chest Press
Upper Back
(Latissimus Dorsi)
Dumbbell Bent-Over Row
Dumbbell Pullover
Seated Row
Cable Pull-Down
Dumbbell Lateral Raise
Barbell Upright Row
Shoulder Press
Cable Upright Row
Front Arms
Seated Dumbbell Curl
Standing Barbell Curl
Dumbbell Preacher Curl
Preacher Curl
Cable Curl
Rear Arms
Standing Dumbbell
Triceps Extension
Cable Press-Down
Table 5.6 Recommended Nautilus machine linear exercises for boys and girls.
Nautilus Exercise* Major Muscle Groups
Leg Press Quadriceps, Hamstrings, Gluteals
Bench Press Pectoralis Major, Anterior Deltoid, Triceps
Compound Row V
(vertical handles)
Latissimus Dorsi, Biceps
Incline Press Pectoralis Major, Anterior Deltoid, Triceps
Compound Row H
(horizontal handles)
Posterior Deltoid, Biceps, Rhomboids, Middle Trapezius
Overhead Press Deltoid, Triceps
Weight-Assisted Chin-Up Latissimus Dorsi, Biceps
Weight Assisted Bar-Dip Pectoralis Major, Anterior Deltoid, Triceps

*Note: Rotary torso machine is appropriate for most children as axis of rotation is through back. Including this machine provides resistance exercise for the midsection muscles (internal and external obliques).

All of our exercisers begin with relatively light weightloads, and progress gradually in small increments (typically two pounds). We encourage at least a minute of rest between exercises until the youth increase both their level of fitness and their familiarity with the training program. We also prefer to teach a few basic exercises and systematically add new exercises when the children are ready for more movements.

Before looking at a sample youth strength training class, consider the following summary of our youth strength training guidelines.

  1. Select basic strength training exercises that address the major muscle groups. Depending on equipment availability and other factors, this could range from four multiple-muscle exercises to 12 single-muscle exercises, with many variations.
  2. Perform 10 to 15 repetitions of each exercise with emphasis on proper technique (slow movement speed, full movement range, continuous breathing).
  3. Increase the resistance by a small amount (about two pounds) when 15 repetitions are completed in good form.
  4. Begin with one set of each strength exercise. If 12 exercises are performed use a single-set training protocol. If six exercises are performed, progress to two sets of each with about a minute rest between sets. If four exercises are performed, progress to three sets of each with about a minute rest between sets.
  5. Exercise two or three days per week, keeping in mind that both training frequencies appear to produce similar strength gains in youth.

Sample Youth Strength Training Class

Our youth strength training classes are 60 minutes long. We spend about 20 minutes warming up; about 25 minutes performing strength exercises and about 15 minutes cooling down. Although the warm up and cool down segments vary, they always include aerobic activity, stretching exercises and light resistance exercises. The following is a typical class format:

Our youth Nautilus strength procedures are similar to our adult exercise protocols with the exception of the repetitions scheme. Because our research indicates that boys and girls make greater strength gains with higher repetitions than lower repetitions, we recommend a two-month introductory training program that begins with 13 to 15 repetitions and progresses to 10 to 12 repetitions. As shown in Table 5.7, we suggest presenting three Nautilus machines during the first two weeks, introducing three more Nautilus machines over the next two weeks, and teaching three additional Nautilus machines over the following two weeks. This progressive program of strength exercise instruction encourages good training technique and enhances machine mastery with minimum confusion on the part of the children.

Table 5.7 Recommended two-month Nautilus strength training program for preadolescent boys and girls.
Weeks Exercises Sets Repetitions
1&2 Leg Press
Bench Press
Compound Row (vertical)
3&4 Leg Press
Bench Press
Compound Row (verticle)
Incline Press
Compound Row (horizontal)
Rotary Torso
5&6 Leg Press
Bench Press
Compound Row (verticle)
Incline Press
Compound Row (horizontal)
Overhead Press
Weight-Assist Chin-Up
Weight-Assist Bar-Dip
Rotary Torso
7&8 Leg Press
Bench Press
Compound Row (vertical)
Incline Press
Compound Row (horizontal) Overhead Press
Weight-Assist Chin-Up
Weight-Assist Bar-Dip
Rotary Torso

Educational and Motivational Techniques

Although the recommended strength training procedures are relatively simple and straightforward, successful implementation typically requires some instructional and motivational skills. Our youth strength training staff try to incorporate the following teaching techniques to encourage purposeful participation and to enhance the exercise experience.

  1. Offer a clear training objective for each exercise session.
  2. Give concise exercise instructions and precise exercise demonstrations.
  3. Provide attentive supervision for all program participants.
  4. Give appropriate assistance whenever necessary, and especially with exercise execution.
  5. Teach one task at a time.
  6. Progress safely and systematically in all aspects of the strength training program.
  7. Give plenty of positive reinforcement for good efforts.
  8. Provide specific information feedback on exercise performance and training progress.
  9. Ask relevant questions to facilitate critical thinking and two-way communications.
  10. Welcome each child to class and commend each child for participating in the exercise program during every training session.


There are few areas in the field of fitness more important than youth strength training. By taking a sensible and serious approach to resistance exercise for children, we can help boys and girls develop both strong musculoskeletal systems and physically active lifestyles that should have lifetime benefits. It is good to know that supervised strength training programs for boys and girls have an excellent record with respect to safety and productivity. Our recommended protocol for effective and efficient youth strength training is eight to 10 basic exercises for the major muscle groups, initially performed for one set of 10 to 15 repetitions, at a slow movement speed and through a full movement range. We also advise that each exercise session include aerobic, flexibility and game activities, as well as relevant fitness information for best overall response and results.


  1. National Strength and Conditioning Association. 1995. Position paper on prepubescent strength training. National Strength and Conditioning Association Journal, 7:27-31.
  2. Faigenbaum, A., Zaichkowski, L., Westcott, W., Micheli, L., and Fehlandt, A. 1993. The effects of a twice-a-week strength training program on children. Pediatric Exercise Science, 5: 339-346.
  3. Faigenbaum, A., Westcott, W., Micheli, L., Outerbridge,, A., Long, C., LaRosa Loud, R., and Zaichkowsky, L. 1996. The effects of strength training and detraining on children. Journal of Strength and Conditioning Research, 10 (2): 109-114.
  4. Westcott, W., Tolken, J., and Wessner, B. 1995. School-based conditioning programs for physically unfit children. Strength and Conditioning, 17: 5-9.
  5. Westcott, W. 1987. Building Strength at the YMCA. Chicago, Illinois: YMCA of the USA.
  6. American College of Sports Medicine. 1990. The recommended quality and quantity of exercise for developing and maintaining cardiorespiratory and muscular fitness in healthy adults. Medicine and Science in Sports and Exercise, 22: 265-274.
  7. Sudy, M. (Editor). 1991. Personal Trainer Manual. San Diego, California: American Council on Exercise.
  8. Cahill, B. (Editor). 1988. Proceedings of the Conference on Strength Training and the Prepubescent. Chicago, Illinois: American Orthopaedic Society for Sports Medicine.
  9. Faigenbaum, A., Westcott, W., La Rosa Loud, R., Long, C., 1999. The effects of different resistance training protocols on muscular strength and endurance development in children. Pediatrics, (in press).
  10. Westcott, W., and Faigenbaum, A. 1998. Sensible strength training during youth. IDEA Health and Fitness Source, 16(8): 32-39.
  11. Westcott, W. 1995. Strength Fitness: Physiological Principles and Training Techniques, Fourth Edition. Dubuque, Iowa: Brown and Benchmark.
  12. Westcott, W. 1995. How to take them from sedentary to active. IDEA Today, 13(7): 46-54.