Axe Throwing: Is It “All In The Wrist”?

Timbersports are increasing in popularity internationally, but there are fewer than five studies available across all disciplines. While two studies have examined trunk mechanics no studies have examined upper extremity kinematics to date. PURPOSE: We conducted an exploratory investigation of the relationship between wrist biomechanics and accuracy among amateur collegiate competitors. METHODS: The commercially available double-bit axe was designed for throwing, with a head weight of 1.35 kg, a bit (cutting edge) length of 15 cm, and a wood handle length exiting the head of 52.0 cm. Throwers stood ~5 m from a southern yellow pine plank target 70.5 cm wide with a 0.25 cm dot for a bullseye at 1.23 m above the ground. Only axes that stuck in the target were counted. We recorded the distance from the center of the bullseye to the nearest point on the bit of the axe, the angle of this line on a vertical plane paralleling the plane of the target face, and the angle of the axe handle perpendicular to the target face. Inertial measurements units on the upper body were used to compute the wrist ulnar and radial deviation at the point of release and wrist velocity. This study is in progress. Thus far, four throwers have completed three trials each. Given the small sample size, all trials were considered a case. RESULTS: Spearman’s Rho indicated moderate correlations between wrist deviation and distance to center, angle of axe on target and angle of the handle on target as well as between wrist velocity and distance to center and angle of handle on target (Table 1). However, confidence intervals are broad and cross zero indicating that some subjects may present with either positive or negative relationships. CONCLUSION: More trials should be captured before making definitive judgements. It’s possible that the relationship between kinematics and accuracy of axe throwing is parabolic rather than linear which would mimic the relationship of release angles and baseball throwing distance. Table 1. - Statistic 95% Confidence Intervals Variable 1 Variable 2 Spearman”s rho Lower Upper Distance to bullseye wrist ulnar/ radial deviation at release 0.43 -0.21 0.81 wrist velocity -0.63 -0.89 -0.07 Angle of axe on target wrist ulnar/ radial deviation at release -0.48 -0.83 0.15 wrist velocity 0.02 -0.57 0.6 Angle of handle on target wrist ulnar/ radial deviation at release 0.47 -0.16 0.83 wrist velocity -0.57 -0.87 0.02