Hi Steve. What you described is pretty much imitating a row with weights, and might be very beneficial for a specific mode of training. However, from my prospective, you might be better off doing general back conditioning, and combining it with some kayaking. For general back, you have to look at the functions. 1. Spinal stabilization 2. Shoulder elevation, and what you are concerned with, scapular retraction, both vertical and horizontal. There is a ton of info on this site describing methods to work these areas (go to the kinesiology section, look under articulations_, but if you chin row, and pick something up off the ground, you'll do just fine.