DETERMINANT FACTORS RELATED TO THE VARIATION IN HORIZONTAL VELOCITY OF THE BODY CENTRE OF MASS IN BUTTERFLY

Abstract

INTRODUCTION: According to Persyn et al. (1995) in the global strokes only the resultant impulse on the body, which is the difference between propulsion and drag forces, can be calculated from one phase to another. Therefore, the horizontal velocity variation of the body centre of mass (CMbody) in a stroke cycle must be calculated. When the horizontal velocity of the CMbody varies considerably, the swimmer has to overcome during each stroke cycle high hydrodynamic drag forces, due to the high peak velocity.