Many athletes and clients I work with lack adequate pillar and shoulder stability. Whether this is related to acquired laxity, inherent instability or simply a lack of proper muscular control, I think it is important to assess baseline stability in anyone performing overhead lifts, ballistic upper body training and in overhead athletes.
In my clinic, I work with lots of baseball players, swimmers and volleyball players. Most females tend to struggle with hyper mobility (loose shoulder joints) whereas many of my males tend to have soft tissue tightness and in some cases limited internal rotation (GIRD). Both males and females tend to have a need to improve dynamic shoulder and pillar (core) stability to reduce injury risk and optimize mechanics.
The following exercise is one I use to both assess anti-rotational control/stability as well as train the body to resist torsional forces. In the video below, you can see how to assess your baseline strength and stability.
This exercise is very effective in working improving glenohumeral and scapular stability as well as enhancing shoulder, torso and hip stability. In my opinion, athletes with poor stability in this assessment should not perform unilateral Olympic lifting or ballistic overhead training as they may lack the necessary neuromuscular control to execute the proper movement pattern.