One thing to remember when learning to incorporate your torso and legs into your kayak stroke is that it will feel easier and those who gauge their sport satisfaction from working hard will be disappointed at first. You will go faster for the same effort, or go the same speed for less effort, both of which are good things J
However, with diligent technical work you will learn to work harder and harder until you eventually surpass the previous level of effort achieved solely through the use of your upper body. As was pointed out earlier; legs and abs should fail before arms if you do it right.
In sport science this is often referred to as an increase in the economy of motion, where economy of motion is the merger of biomechanics and physiology into performance. It is very sport, velocity and power output specific. Sprint specific economy will not help marathon paddlers and vice versa. The only odd balls in this mix are open ocean paddlers who need both high speed economy (for surfing) and steady state economy (when there is no surfing to be had). As we have previously discussed, top ski paddlers have skill profiles when surfing and much of that has to do with who is efficient (economical) at what velocities. Greg is very economical at lower speeds and catches lots of “low speed” bumps while Oscar is economical on “higher speed” bumps and makes good use of those when they come by.