Using the underhand grip on a band or cable helps tap into more corrective-based ranges of motion for the shoulder and upper back while learning to stabilize the thoracic spine and shoulder blade during dynamic rotational movements at the true shoulder joint itself.
This variation requires lighter loads and slower, more controlled movements in order to avoid flaring up the shoulders or placing undue stress over the rotator cuff or other acute muscles being loaded. Set your ego aside and load this movement properly in the 6-12 rep range with total control and stability. The activation benefits will become readily apparent.
We love the workouts that make you ache, the ones that make you shake your fist at the heavens above. This one involves doing one-rep maxes with 60-second negatives, followed by some nice drop sets.
Lots of the usual solid folksy wisdom from Dan John, but in addition, this article contained so many great training ideas that we dropped what we were doing and ran straight to the gym to try them. (Sorry Ma, we'll fix your dialysis machine tomorrow.)