High-speed video analysis of arrow behaviour during the power stroke of a recurve archery bow

Abstract

The manner in which an archer holds and releases the string of a recurve bow causes the arrow to flex during the bow’s power stroke and on its way from the bow to the target. While an experienced observer can subjectively evaluate an arrow’s pitch and yaw visually after it has left the bow, the arrow’s behaviour during the bow’s power stroke happens too quickly for visual observation. High-speed video is consequently a much more effective tool. Similarly, high-speed video is an effective tool for studying an archer’s technique during the bow’s power stroke. Mathematical models of the arrow’s behaviour in the horizontal plane during the bow’s power stroke have, to date, relied upon comparison of the arrow’s flexural shape with photographs. However, an implicit assumption of that process is that the archer’s technique is perfect. This paper provides an analysis of event times and the magnitudes of several key components of the arrow flex during the bow’s power stroke for sixteen world-class archers. Aside from being a powerful analysis tool in its own right, that data can also be used to evaluate mathematical models of arrow behaviour. It is concluded that archer technique variations could be a significant source of error where a single archer is used as a comparison for the mathematics, even if that single archer is amongst the world’s best.