My son started training about 2 years ago & has progessed from a 19 year old 82kilo fatty to a pretty well put together 21 year old, 96kilo,12% body fat big boy.His problem is his chest has lagged behind because his massive delts just take over on chest work. He also has trouble training both chest & shoulders as his shoulders pop out!! Is there any exercise that will build his pecs where his shoulders will not take over & pop out?