Ending the stroke at the knee minimizes yaw and lessens need for correction. Keeping the top elbow(grip arm elbow) straight keeps the paddle shaft vertical to the water. The shoulder never enters into the equation unless you pull the paddle in back of the frontal plane of the torso. You might review ACA paddling concepts. Its good to go over them from time to time.
Charlie' referring to keeping a powerful stroke. Most paddlers in tripping situations let their grip hand wander in board, but not so much as before thinking vertical paddle. Vertical really forces you to use your body to pull the boat past the paddle and mitigates shoulder and arm cramping.. Its been years since I had the dreaded shoulder blade cramp after a long day.
Charlie' referring to keeping a powerful stroke. Most paddlers in tripping situations let their grip hand wander in board, but not so much as before thinking vertical paddle. Vertical really forces you to use your body to pull the boat past the paddle and mitigates shoulder and arm cramping.. Its been years since I had the dreaded shoulder blade cramp after a long day.