Problem solved,
Thanx everybody for the great help!
Got the bodybuilders to strengthen their rotators, was helpfull, ontop got them to build up their rhomboids - after that even better, although some hihgher friction on plexus occured - gave them self-mobilisation for it working slightly into ULNT - after that GONE!
we´re now fixing it with mostly lumbar stab and got a shrink working their overtraining and overintension workouts ;-)
Thanx all again