Absolutely Graham. The core muscles of the body are responsible of the body rotation that powers the arm into the point where the lats an the arm muscles initiate the pull phase of the stroke. This, combined with the fact that a 20 - 30% improvement was possible with technique ( rather that a 20-30% increase in cv fitness) I think supports the arguement that swimming front crawl isnt as specific a dive fitness assessment as other forms of exercise would be. As a GUE Instructor I don't imagine you do much in the way of body rotation and arm swimming as it would have the rather unfortunate side effect of ruining your fabulousness!![]()