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Hand Force and Swimming Velocity
Rod Havriluk, Ph.D.
XVth Federation Internationale de Natation World Congress
Indianapolis, IN, 2004 The relationship between force and velocity in swimming has been investigated under both passive and active conditions. The most basic form of the equation is expressed as: D = kvn, where D is the drag force on the body; k includes the coefficient of drag and an area variable; and v is the swimming velocity raised to an exponent of n. A wide range of values for the velocity exponent has been determined. Values were calculated for passive drag from 1.66 to 2.42 (Shimonagata, Taguchi, Taba, & Aoyagi, 1999) and for active drag from 1.2 (di Prampero, 1986) to 2.76 (Nomura, 1994). Non-quadratic equations have also been used (Keskinen, Tilli, & Komi, 1989). A recently conducted meta-analysis on passive drag confirmed the quadratic relationship between resistance and velocity (Havriluk, 2004). If the resistance increases quadratically with velocity, then propulsion must increase in the same manner. The purpose of this study was to determine the relationship of hand force and swimming velocity. It was hypothesized that there would be a quadratic relationship between force and velocity. Method The subjects were competitive swimmers between the ages of 16 and 23. Hand force and swimming velocity were measured with Aquanex. The instrumentation and testing protocol were originally described and validated in 1988 by Havriluk. Subsequent studies confirmed the validity of Aquanex for measuring forces in aquatics (Prins, Hartung, Merritt, Blancq, & Goebert, 1994; Prins & Havriluk, 1991; Havriluk, 2003).

Pressure sensors were placed on the swimmer’s hands. Each swimmer was asked to sprint crawlstroke over a 20 m distance to a wall. Data were collected at a rate of 85 samples per sec over the last 10 m of the swim. Average hand force and swimming velocity were calculated. The above figure shows the force