Here’s a little something on the upper limb, highlighting why we teach lower and central zones before coming to the upper limb. It might be an older paper, but the findings still stand:
Elliott B, Fleisig G, Nicholls R, Escamilia R. Technique effects on upper limb loading in the tennis serve. J Sci Med Sport. 2003;6:76–87
This tennis study showed that not adequately flexing the knees in the cocking phase of a serve resulted in a 17% increase in shoulder load and a 23% increase in elbow valgus load when compared to players who did flex their knees adequately while serving at a comparable speed.
In other words, rotator cuff exercises and scapular stabilisation do not hold all the answers!