'Mass moves mass' was no doubt the theory applied here for the powerlifting, if they're too young to build muscle then he probably reckoned the only 'advantage' was extra mass of added fat.
Back when I was young, children weren't allowed to lift weights in gyms, they had to be over 12, so basically when they're mostly old enough to start building muscle, as I guess the belief at the time was that without muscle growth it would be putting all the strain on their joints?
