The swaying produced by the kettlebells extended center of mass will exagerate the imperfect path the bar is travelling and teach the athlete to create a much more vertical bar path.
Remember the shortest distance bewteen to point is a straight line.
Alongside better benching technique you will also challenge the rotator cuff ability to create balanced tension.
work with 40% of the athletes 1RM and try to perform 5 Reps.
Keep me posted if you decide to use it!
Ash Allen - Personal Trainer - Amsterdam