half the boys would have given that kid either a run for his money or beaten him. A quarter of the rest would have been able to complete that course, but would have lagged while the remaining boys in that group would have not been able to complete that course. It wasn't weird or strange to do stuff like that as a kid and compete with each other on the playground as well as after school outside.

Sure the father in this video set this up as a training mechanism, however I am not buying the bilateral rotator cuff tears and arthritis arguments. Sure some may risk said injuries in life, however many wouldn't. I even played baseball and threw a mean curveball although my dad coached against this, Played tennis as well. No rotator cuff injuries to this date and I am fifty six. So the normal wear and tear is different for each person and yes if that kid is genetically predisposed to wear and tear you may be right, but to throw that out there as a fact, not true. not true at all.