Training and Exercise for Children and Teenagers - Part 3

Doug Lawrenson
Written By: Doug Lawrenson
December 22nd, 2007
Updated: June 13th, 2020
Categories: Articles Training
43.1K Reads
This is part 3 in our 4 part series on weight training for teens and children. This part looks at exercise guidelines for resistance training.

Training and exercise for children and teenagers. This article is huge! So huge it has been split into a 4 part series. You can see the 4 parts below or click the continue link at the bottom of each part.

Part 3: Guidelines for Exercise Prescription

As with any form of exercise or sport, you should be given the ok from your doctor to make sure it is ok for you to perform weight training.

The optimum amount and type of exercise to recommend to young children and adolescents has not been defined precisely but should be individualized based on maturity level, medical status, skill level, and prior exercise experiences. Several health agencies encourage people over the age of six years of age to accumulate at least 30 minutes of moderate intensity physical activity on most and preferably all days of the week. In older children and teens it is recommended 20-30 minutes of vigorous exercise at least 3 times per week is encouraged for greater benefits. Children typically do not need a heart rate prescription to regulate intensity because they are at a low cardiac risk and generally have good ability to adjust exercise according to tolerance of perceived exertion. Muscular strength and endurance are important components of fitness in young people. Available evidence suggests that children and adolescents can participate safely in properly designed and supervised resistance training programs.

After puberty and during adolescence with the accompanying hormonal changes, children begin to undergo greater physical changes as a result of a weight training program. During this time they should maintain strict exercise form and close supervision from a qualified adult. Boys at this age have an overwhelming urge to find out who can lift the most weight for one repetition. But what they normally find is that that little bit of ego training normally results in an injury. There is no place for egos in weight training. And the ego should be left outside the gym. As young people approach full growth and physical maturity, weight training can have its most dramatic effects on performance, appearance, and self confidence. This is a time when can handle heavier exercise loads and more intense exercise programs. However the emphasis must still be on exercise technique. Trying to move heavier weights too early can result in injury. Exercises that are performed correctly rarely resort in an injury.

Whenever you start a new sport or activity, start out slowly so that your body get used to the increases in activity. Even if you think you are not exerting yourself very much, if you’ve never used weights before your muscles may be sore the next day. And, because of something called delayed onset muscle soreness (DOMS), the pain may be at its worse 2 or 3 days after your first training session.

Before starting a training session warm up the muscles by spending 5-10 minutes on a piece of cardiovascular equipment such as a stationary bicycle, jogging machine, or rowing machine or even by a jog or brisk walk. This should be followed by stretching all muscle groups. After finishing your training, cool down by again performing some cardio and stretching of the muscles that have been trained.

Dynamic Resistance Training.

This type of training is suitable for developing muscular fitness of both sexes including children. Dynamic resistance training involves concentric and eccentric contraction of the muscle group performed against a constant or variable resistance. For this type of training people typically use free weights (barbells and dumbbells), and constant or variable resistance machines.

Several important concepts used to prescribe resistance training programs are intensity, repetitions, sets, training volume, and the order of exercises. Intensity is expressed either as a percentage of the individuals one repetition maximum (%1-RM) or the repetition maximum (RM), which is the maximum weight that a person can lift for given number of repetitions of an exercise (e.g., 8 RM equals the maximum weight that the person can lift for eight repetitions) For the number of repetitions (i.e., 1 to 10 RM) corresponding to various percentages of 1-RM (i.e., 75 to 100% of 1-RM) The %1-RM values and number of repetitions for intensities less than 1-RM are:

  • 60% 1-RM = 15-20 RM
  • 65% 1-RM = 14 RM
  • 70% 1-RM = 12 RM.

Intensity is inversely related to intensity repetitions. In other words, people who are able to perform more repetitions using lighter resistance or weights and fewer repetitions using heavier resistance. A set consists of a number of consecutive repetitions of the exercise. Training volume is the total amount of weight lifted during the workout and is calculated by summing the weight, repetitions and sets for each exercise. The optimum training stimulus for strength development is high intensity, low repetitions, whereas low intensity, high repetition optimise muscular endurance gains. Although novice weight lifters experience muscular fitness gains from low training volumes (one to two sets using moderate resistance and repetitions, 2 days per week), and for advanced lifters they may need larger training volumes (e.g., 3-4 sets, 3 to 4 days per week).

The table below presents guidelines for healthy adults, older adults, and children who are beginning a resistance training program. For trainers with resistance training experience, they would need to modify the guidelines based on their goals, initial muscular fitness level, and the time available for exercising. You can tailor dynamic resistance training programs to optimise the development of muscle strength, tone, size (hypertrophy), or endurance by varying the intensity, repetitions, sets, and frequency of training.

Guidelines for Resistance Training (ACSM 2000)
Type Intensity Repetitions Sets Frequency No of Exercises
Healthy Adults 70-80%
1 RM
8-12 >1 2-3 8-10
Older Adults (1) 60-75%
10-15 >1 1 min 8-10
Children (1,2) 70-80%
8-12 1-2 2 8-10
1. Multijoint exercises are recommended for children and older adults
2. Programs for children and adolescents should be supervised closely by instructors

The table given below presents guidelines for designing types of resistance training programs for novice, and advanced weight trainers. Exercises can be found in the exercise section of this website.

Guidelines for Resistance Training Design
Type Intensity Repetitions Sets Frequency Length of Program
1 RM
8-12 RM >1 3 6 weeks or more
1-6 RM >3 5-6 12 weeks or more
Toning 60-70%
12-15 RM >1 3 6 weeks or more
Endurance <60 % 1 RM 15-20 RM >1 3 6 weeks or more
1 RM
10-12 RM >3 3 12 weeks or more

The following guidelines and principles are offered as suggestions to those interested in developing sound strength training programs.

  1. All strength training activities should be supervised and monitored closely by appropriately trained personnel
  2. No matter how big, or strong, or mature the individual appears, remember that the child or adolescent male or female is physiologically immature
  3. The primary focus, at least initially, should be directed at learning proper techniques for all exercise movements and developing an interest in resistance training.
  4. Proper techniques should be demonstrated first, followed by gradual application of resistance or weight.
  5. Proper breathing techniques (i.e., no breath holding) should be taught.
  6. Stress that exercises should be performed in a manner in which the speed is controlled, avoiding ballistic (fast and jerky) movements.
  7. Avoid the practice of powerlifting, and bodybuilding.
  8. Perform full range, multijoint exercises (as opposed to single joint exercises).
  9. Make sure the participant can understand and follow directions.

All strength training should follow approved intensity, sets, and frequency guidelines established for young people.


Avoid repetitive use of maximal amounts of weight in strength training programs until reaching adolescence level of developmental maturity. It is not recommended that resistance training be performed to the point of muscular fatigue.

To optimise strength gains, the intensity should be set at 75-90% 1-RM. At this intensity, most individuals will be able to perform 4-10 repetitions (4-10 RM) of the exercise. For high intensity strength training programs, the intensity usually ranges between 1-6 RM; for non-athletic populations, moderate intensity programs (8-12 RM) are generally recommended. However, when your primary goal is to develop muscular endurance an intensity of <60% 1 RM (15-20 RM). Although low-to-moderate intensity is best suited for muscular endurance and toning with which some strength gains may be experienced. The degree and rate of strength gain however will be less than with a program designed specifically to optimise strength development (specificity principle). For advanced strength training and hypertrophy (muscle growth) programs, individuals achieve large training volumes by increasing the number of sets, performing multiple exercises for each muscle group, and increasing the frequency of training. For programs specifically designed to increase muscle size, you can also maximise training volume by using combinations of moderate intensity and repetitions.


The optimum number of sets for improving muscular strength is somewhat controversial and depends on your specific goals. Research studies suggest that single set (one set per exercise) programs are just as effective as multiple set (two to three sets per exercise) programs for untrained people and recreational weight lifters during the first three to four months of resistance training. The ACSM recommends a minimum of one set of 8-10 different muscle groups to improve muscular strength of apparently healthy adults, older adults, and children. A major advantage of a single set program is that the average amount of time required to complete the program is much less than for multiple set programs, thereby potentially increasing your compliance. However, for serious trainers, powerlifters, and bodybuilders engaging in advanced strength training and hypertrophy programs should use sets using periodisation techniques to optimise strength gains.


Improvements in muscular fitness may result from exercising just one day per week, especially for people with below average muscular fitness. However, research suggests that training three days per week is superior to one to two days per week for optimising strength gains of the chest, arms, and leg muscles. You should allow at least 48 hrs of rest between workouts to allow the muscles to fully recuperate and to prevent injury from overtraining. Increasing the frequency of workouts is one way to achieve the high training volume necessary to stimulate gains in muscle strength and size for advanced resistance training programs.

Order of Exercises.

A well rounded exercise program should include at least one exercise for each of the major muscle groups in the body. In this way, muscle balance – that is, the ratio of strength between opposing muscle groups (agonists vs. antagonists, contralateral muscle groups (right vs. left side), and upper and lower body muscle groups can be maintained. Order the exercises so that you first execute multijoint exercises such as the seated leg press, bench press, and lat pull down – that involve larger muscles (e.g., gluteus maximus, pectoralis major, and latissimus dorsi) and more muscle groups, before progressing onto the single joint exercises for smaller muscle groups. To avoid muscle fatigue in novice weight lifters, arrange the exercises so that successive exercises do not involve the same muscle group. This allows time for the muscle to recover.

This article continues in part 4 - the workouts >>