How to use the youth training intensity calculator
Enter a target rep count and the tool reverses out what percent of a one-rep max that load represents, using both the Epley and the Brzycki formula. That means intensity can be handled as a number without ever testing a one-rep max. Add the load that allows those reps and an estimated 1RM appears too. Enter one repetition and both formulas simply take that load as the max.
The belief that growth plates make resistance training unsafe for teenagers is widespread, but there is no scientific evidence that strength training stunts height. Several reviews reach the same conclusion, and the mechanical loading of resistance exercise is reported to look beneficial for bone formation and growth. The American Academy of Pediatrics and the National Strength and Conditioning Association have both issued position statements supporting youth resistance training. What actually causes trouble is not the training but unsupervised max attempts, loads chosen to outlift a friend, and reps continued after form breaks down, as of October 2026.
There are limits. Both formulas are estimates built on adult data, individual variation is wide, and past about ten reps they drift apart. That is why both values are shown and neither is declared correct. The calculation also says nothing about how many sets to do or which lifts to include.
Do not attempt a one-rep max test without supervision. The point of this tool is that the test can be skipped and intensity still managed. Learn the movement first, control the full range with a light load, and only then add weight, with a coach able to watch the lift. If a sharp, pinpoint pain appears at a joint, stop that lift and see a clinician.
Frequently Asked Questions
There is no scientific evidence that it does. Several reviews found none, and the mechanical loading of resistance exercise is instead reported to look beneficial for bone formation. The American Academy of Pediatrics and the National Strength and Conditioning Association have issued position statements supporting youth resistance training.
Both are estimates, and there is no basis for calling one correct. They sit close together at low rep counts and spread past ten reps, so treat the pair as a range and add weight from the conservative end.
The purpose of this calculation is to skip that test. Pick a target rep count and you get the percent of 1RM it corresponds to, so adjusting load by rep count keeps intensity under control without ever going for a maximum.