[mattd8a]

Poor rhom strength and lack of serratus control, can lead to hypertrophy of Lat Dorsi, match that with too much anterior strength (Delt and Pec Minor/major) and you can end up with clunking shoulder. Assess bulk of Lat Dorsi, as he may have developed a shoulder stabilisation strategy where he utilises lat dorsi to clamp downlimiting the rotation of scapula. Is it bilateral or unilateral? Any indication of nerve problems (long thoraccic, dorsal scapula control rhoms and serratus I think]?) Any other muscle wasting/hypertrophy (e.g. traps and delts) major protraction in shoulders? greater unilaterally? Evidence of scapula winging?
Am sure you have it sorted by now but just a few ideas