This is an excerpt from a blog post I did for Daily Gaines:
The Overhead Carry is a well-known movement that can train overhead strength as well as shoulder and core stability. It can also be used as an assessment tool to help guide therapeutic and corrective interventions so that your athlete can continue to progress their overhead lifting safely. 
Life and sport take place in 3 planes of motion, therefore training & mobility work should reflect that. Depending on the type of weighted modality, this movement can be biased for strength, stabilization or assessment. In the video below we use a med ball atop a flat hand and extended wrist to take a look at the athlete’s stability and mobility through all 3 planes. The ball is resting on the hand, so as form breaks down it will roll out of place or compensatory patterns will present themselves.
For the full blog post and more great sports performance content, check out DailyGaines.com
Chris Butler Sports PT 