My so called evidence is all anecdotal and tells me that he should not start training with weights
until he is older. How much older I don’t know but at least until he starts shaving, grows underarm
and pubic hair and his voice changes. Then wait a bit. I would actually request a complete blood test
now and annually moving forward. They will be valuable reference points. You will thank me later.
Until then he can and should do all the controlled bodyweight exercise he desires . . . squats (100 reps),
chins, dips, pushups (100 reps), etc. His body (and you) will ultimately govern his frequency and intensity.
My opinion would be to avoid bench presses like the plague. Same with any ballistic movement
movements like Olympic lifts and heavy deadlifts. For the time being, I would stick with safe controlled
compound bodyweight movements and avoid those I mentioned above.
All of which reminds me of Balanchine's views on the importance of proper training, captured in
his 1945 essay, "Notes on Choreography," He certainly recognized the physical vulnerability of children:
“Even with eight- or nine-year-old children, we must always keep in mind the fact that their bones
are still soft and their muscles (particularly the ones around the knee) are still unformed. For this
reason one should never force the feet of children to attain perfect ballet positions, nor insist on
their making an effort to turn out their legs.”
While you son is not that young or engaged in the same activity, but I think his principle holds true
with his respect of youth, their exuberance and the long term effects of any physical training when
starting at an early age.
To wrap this up . . . if he is as big and as strong as you say he does (not doubting) he may not need
much in the way of strength training. What are his goals would be a question I would ask first.
There is plenty of time to engage in weight training . . . time is on his side . . . but knowing me at his
age, that sort of talk meant nothing.
I am sure you are a great Dad and will ultimately make the right choice for you son.
Hope helps.