Great info there, Peter. So the first component is to make sure that one has a proper consistent swing that can bring the head back to the ball at the sweet spot, with the head square and at the correct angle for the optimum launch angle.

As for swing speed, I'm really not sure if strength and fitness are what the average Joe lacks, but I suspect it's more of a technique issue of learning how to create the most lag and conserve the top speed for the moment of impact.. Perhaps I might even suggest that if your driver shots go say anywhere below 220 then you need to work on technique. But if it's already going beyond say 240 then yes you might need to work on strength and fitness (assuming sweet spot, launch angle and spin are optimum)?