Dart throwing by prosthesis users - unexpected advantages

1. Dart throwing by prosthesis users - unexpected advantages Jenna Sabato, Jack DeVillez, Goeran Fiedler Asia-Singapore Conference on Sport Science, Singapore, 18th - 19th July 2019

2. Popularity of Darts • Sizable numbers of athletes play darts professionally • WDF Rankings • 408 women • 1,283 men • Darts competitions have huge prize money in championships • BDO World Darts Championship ……$473,000 • World Masters …………………………$84,000 • Dutch Open ……………………………$41,000 • Dedicated fan following in much of the world • https://www.youtube.com/watch?v=pGNZ3GqYrVY

3. Background • According to the World Dart Federation, there are currently no rules or regulations pertaining specifically to this topic • Rules include the player’s attire and player conduct • Rules for disqualifications • Throwing kinematics have been studied • The Biomechanics of Throwing: Simplified and Cogent • Weber, et al. Sports Med Arthrosc Rev. 22.2 (2014): 72-79. • Kinematic and Kinetic Profiles of Trunk and Lower Limbs during Baseball Pitching in Collegiate Pitchers • Kageyama, et al.  J Sports Sci & Med 13.4 (2014): 742. • Sequences of upper and lower extremity motions in javelin throwing • Liu, Leigh, and Yu. J. Sports Sci 28.13 (2010): 1459-1467. • Lower Extremity Muscle Activation During Baseball Pitching • Campbell, Stodden, and Nixon. J Strength Cond Res  24.4 (2010): 964-971.

4. Hypothesis • The weight and length of a lower limb prosthesis can provide a mechanical advantage in throwing darts

5. Protocol • Participants for this IRB approved study were recruited from the health local student and staff population. • Subjects were instructed to aim for the center of paper targets set up as modified dart board in accordance with official darts rules. • 2D video recording from sagittal • Ten darts per condition • Three conditions in randomized sequence • Baseline • 10 cm leg extension on trailing leg • 4.5 kg cuff weight on trailing leg • Analyze throwing accuracy, forward lean

6. Results (n=13) • Accuracy not significantly different between conditions (p = 0.35). • weighted and the lengthened condition resulted in about 11% and 5% improvements, respectively Up: Sample target with color coded hits for each condition and respective representation in the analysis program Below: Average deviation of hits from the bulls-eye by subject (left) and overall (right) 10.29 cm 9.15 cm 9.77 cm 6

7. Results continued (n=7) • On average, participants were able to get 9.15cm closer to the target with the 6-inch extension on their trailing leg (p = 0.026). • Differences between baseline and weighted condition were likewise significant at the 0.05 level (p = 0.034) • No significant differences in elbow angle and lead leg angle

8. Conclusions • Use of a counterweight or an extension on the balance leg of a dart player allows the player to lean further over the throw line and closer to their target • While overall, group accuracy did no increase, some individuals saw improvement to their accuracy • Lack of accommodation time and heterogeneity of sample (darts expertise, throwing stance) posed limitations • Transferability of findings to amputee population not proven • However, a range of prosthesis weights and lengths is known to be tolerable • With so much at stake in major dart competitions, amputees could make simple adjustments to their prosthesis to gain an edge.

9. Dart throwing by prosthesis users - unexpected advantages Jenna Sabato, Jack DeVillez, Goeran Fiedler Asia-Singapore Conference on Sport Science, Singapore, 18th - 19th July 2019