Effects of long distance running on pre-adolescent children

OK, I’m getting more out of the search function tonight. Not long ago, “gymrob” posted on a phys education thread that

" Anaerobic-lactic loads: As has been said by Charlie, Number 2 and James in the past on this forum it is not smart to make young kids overdo exercises that accumulate lactate. It can lead to Left Ventricle Hypertrophy."

can anyone direct me to the literature on this? I do not believe it is in Drabik’s work.

Thanks!