How Much Weight Should be Used in Strength Training?

Patient Presentation
In the middle of a busy clinic, the triage nurse said she had a telephone call from a mother who wanted to know about her 15-year-old male and how much weight he should be lifting for his weight training. The pediatrician smiled and said, “That’s a small question with a big answer. It really depends on many things and there isn’t a specific amount I can tell you. It depends on his puberty status, why is he doing the training, who is supervising, and many other questions.” The nurse said she would convey this to the mother, and had already noticed that he had his health maintenance examination appointment scheduled for the following week. “I think that we can discuss this issue at that appointment, but he should use reasonable care if there are weight lifting questions before then or they can try to move the appointment earlier,” he counseled.

The benefits of strength training includes improved performance, injury prevention and rehabilitation, improved cardiovascular fitness, improved bone mineral density, improved blood lipid profiles and mental health. The most common risk is injury and most of these “…occur on home equipment with unsafe behavior and unsupervised settings.” Children with a variety of health problems should be evaluated first including hypertension, congenital heart disease, previous use of cardiotoxic medication, seizures, obesity, and Marfan syndrome. Other counseling issues regarding strength training include discussing with the child, teen and family the possibility of eating disorders, distorted body image, and the use of anabolic steroids and other substances.

The American Academy of Pediatrics (AAP) recommends not to begin strength training until at least 7-8 years or when balance and postural controls skills have matured to adult levels which is around this age. There are other general pragmatic considerations too. The child should be able to listen, wait, understand and follow the instructions of an adult. They should have some body sense and control over their body so they can perform the exercise properly, and make the necessary adjustments when they are not doing it properly. Children should be enjoying the activity and not feel coerced to initiating or continuing the activity. These are sensible considerations for any sport. Children and adolescents should perform more repetitions of the exercise using a low amount of weight (i.e. increased weight with fewer repetitions is not recommended). Explosive, rapid lifting of weight is not recommended. Similarly there are no specific ages when an adolescent can begin power training, body-building, or maximal lifts, but many experts including the AAP recommend after the adolescent is skeletally mature to mitigate the risks to the bones, tendons, ligaments and muscles themselves.

Children and teens should have supervision so they can learn to perform the exercises properly initially, receive feedback and have ongoing monitoring so that they continue to perform the exercises properly. Supervision also about numbers of repetitions and weights for workouts can also be devised and monitored. Children and adolescents also do not always use the best judgement and adult supervision can help to ensure safety in the weight room.

Learning Point
As with many things in life, slow and steady strength training can pay dividends. Improvements in strength can be found in properly structured programs of at least 8 weeks duration occurring at least 1-3 times/week. Strength training more than 4x/week does not add to strength and may lead to overuse injuries. Gain in strength, power and muscle size are lost after ~6 weeks of discontinued resistance training.

A 2020 narrative review recommended the following specifics regarding strength training:

  • Prepubertal (pre-peak height velocity)
    • Training focus is on learning the proper movements and techniques
    • General strength training is recommended with emphasis on functional movements
    • 1-3 sets of 8-10 repetitions per training session
  • During puberty (at peak height velocity)
    • Training focus continues on the foundation movements and techniques but also with increases in load and intensity
    • Strength development with increases in training intensity
    • 2-3 sets of 6-8 repetitions, load is 70-80% of maximum strength for 1 repetition (other authors use 60-80% of maximum strength, another author says 8-15 repetitions)
  • Post puberty (post peak height velocity)
    • Training focus continues on function movements, high-intensity loading and increase in intensity
    • High intensity resistance training with traditional and weightlifting movements
    • 3-4 sets x 1-6 repetitions at 70-100% of maximum strength

Questions for Further Discussion
1. When a youth wants to “bulk up” for sports, how much weight gain is advised? A review can be found here
2. What qualifications are required for an adult to supervise youth strength training in your local schools?
3. How do you diagnose hypermobility? A review can be found here

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Exercise for Children and Sport Fitness.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Council on Sports Medicine and Fitness. Strength Training by Children and Adolescents. PEDIATRICS. 2008;121(4):835-840. doi:10.1542/peds.2007-3790

Behringer M, Vom Heede A, Yue Z, Mester J. Effects of resistance training in children and adolescents: a meta-analysis. Pediatrics. 2010;126(5):e1199-1210. doi:10.1542/peds.2010-0445

Lesinski M, Prieske O, Granacher U. Effects and dose-response relationships of resistance training on physical performance in youth athletes: a systematic review and meta-analysis. Br J Sports Med. 2016;50(13):781-795. doi:10.1136/bjsports-2015-095497

Zwolski C, Quatman-Yates C, Paterno MV. Resistance Training in Youth: Laying the Foundation for Injury Prevention and Physical Literacy. Sports Health. 2017;9(5):436-443. doi:10.1177/1941738117704153

McQuilliam SJ, Clark DR, Erskine RM, Brownlee TE. Free-Weight Resistance Training in Youth Athletes: A Narrative Review. Sports Med. 2020;50(9):1567-1580. doi:10.1007/s40279-020-01307-7

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa