WHAT THE HELL DOES HIS TRAINER ASKED HIM TO DO? DOES HE WANT TO MAKE HIS CORE STRONG?
If yes, maybe all the kids should go to the school carrying the school bag in one side of the shoulders, as happened in the past. I though, it wasn't a good practice, if we want to avoid back problems.
Poor guy, and DUMB TRAINER, before he makes his core strong, he is going to destroy his back.
The said is, the client is spending money, he is getting tired, and as benefit, he is going to have back problems.