The short answer
Supervised, appropriately programmed strength training is safe for children and adolescents, and the major paediatric sports medicine and strength and conditioning organisations have said so consistently for more than two decades.
The relevant comparison is not strength training versus doing nothing. It is strength training versus playing three matches a week on an unprepared body, which is where the actual injury risk in youth sport sits.
What the evidence shows
- Injury rates in supervised youth resistance training are lower than in football, rugby, gymnastics and most other youth sports.
- No controlled trial has demonstrated a negative effect on growth, maturation or final height.
- Strength and neuromuscular training programmes reduce overall youth injury risk substantially.
- Bone mineral density, motor competence and confidence all improve alongside strength.
Where risk actually comes from
- Unsupervised training, particularly maximal lifts learned from social media.
- Ego-driven load selection with breakdown in technique.
- Jumping straight into advanced lifts without a movement foundation.
- Weekly volume increases of more than roughly 30%.
- Training through pain that persists more than 24 hours.
- Fatigue: heavy or technical work at the end of an exhausting sport week.
What safe programming looks like
Two to three sessions a week on non-consecutive days. Sets of 8–15 repetitions with control on every rep. Progression through technique, then range, then tempo, then load. Rest between sets that allows the next set to be as good as the last.
Supervision does not require a private coach. It requires an adult who can watch the movement, stop the set when quality drops, and resist the temptation to keep adding weight because the athlete can move it.
Special considerations during growth
During a rapid growth spurt, coordination temporarily declines and growth plates are more sensitive to traction. This is a reason to keep strength training and hold volume steady, not a reason to stop.
If a growth-related condition such as Osgood-Schlatter or Sever's disease is already present, strength work remains central; it simply starts with isometrics and controlled range and progresses as symptoms allow.
Practical safety checklist
- Can they perform the movement well with bodyweight before load is added?
- Is the last repetition of the set as clean as the first?
- Are they able to talk you through what they are doing and why?
- Is soreness settling within 24–48 hours?
- Is total weekly load, sport plus training, being tracked in one place?