My 11 year old son recently visited a physical trainer/chiropractor as part of a free promotion they were offering for athletes. He evaluated him for range of motion and strength and wants to adjust his pelvis (says it's tilted somehow and he isn't getting as much as power as he could) and start him on an exercise program. My wife and I are reluctant to have him do the adjustment but aren't very knowledgeable on the process. Does anyone have any experience with this?