Case Study: Effect of Handrim Diameter on Performance in a Paralympic Wheelchair Athlete

Abstract

This study, with a top T-52 class athlete, determines the relationship between stroke frequency (SF) and push time (PT) and wheelchair velocity (Wv) using different handrim diameters (HD) and the effect of different HDs on the athlete's heart rate (HR) and blood lactate (LACT) at competition speeds. Wv shows a linear-direct relationship with SF but a linear-inverse relationship with PT (p < .001 in both cases). Using bigger handrims (0.37 m instead of 0.36 m), SF increases 6%, while PT decreases 27% (at 24 Km·h −1 ). HR (p < .0001) increases with Wv and is also affected by HD with differences between the 0.34 m-0.36 m handrim group (lower values) and the 0.37 m handrim (higher values). Significant interaction (p < .0001) is identified between HD and Wv. LACT results seem to follow the same direction as HR. This methodology helped the athlete to choose the optimum HD, and his achievements (some world records) indicate that HD optimization could be highly profitable in sport terms.Attaining peak performance in sports generally requires not only great care of many aspects in everyday life and an adequate planning of training but also constant work in optimizing small details that can often make the difference between real success and a good result. In wheelchair athletics, paying attention to the equipment, especially the wheelchair and its components, seems to be relevant, but research is actually more focused on mechanical efficiency in relation with the mechanical power that the athlete can produce, a great deal of which is lost (frequently more than 90%;

Constraints influencing sports wheelchair propulsion performance and injury risk

“…Coutts [24] suggested that the greater hand rim diameters of the wheelchair basketball players allowed them greater time to apply propulsive forces (impulses) and hence develop greater levels of acceleration as required due to the stop-start and change of direction nature of wheelchair basketball. This view of Coutts [24] was supported more recently by Costa et al [23] who examined the relationship between stroke frequency, push time and wheelchair velocity using different hand rim diameters in a class T-52 wheelchair track athlete. They found that when greater torque is needed for rapid speed increases, a larger diameter hand rim could be more effective due to its longer lever arm.…”

“…Wheelchairs can now be altered in many ways and a variety of studies [23-25] have shown that the chair set up can alter propulsion biomechanics in ways that may be beneficial for both sport performance and reducing injury risk.…”

The Ergonomics of Wheelchair Configuration for Optimal Performance in the Wheelchair Court Sports

“…Yet, as a possible result of only being a recent 10 innovation in the court sports, no research into the effects of differing hand-rim diameters on 11 the performance of maximal effort tasks, specific to the wheelchair court sports, exists. The 12 effects of this on aspects of mobility performance is something which has received previous 13 research attention from a daily life [63] and wheelchair racing [64][65][66] perspective.…”

“…Woude et al [64] revealed that manipulating hand-rim 6 diameter/gear ratio did not affect the temporal parameters during sub-maximal wheelchair 7 propulsion, whereas Costa et al [66] observed an increase in push frequencies and a reduction 8 in push times in the larger diameter hand-rim. However, it must be reiterated that the latter 9 was a single participant case study, whose results are unlikely to be representative of the 10 population of wheelchair athletes.…”

“…[64] and Costa et al [66] noted that the majority of participants could not maintain the highest 17 test velocity in the largest hand-rim condition. Therefore, there are potential implications 18 applicable to the wheelchair court sports that would merit investigation, as these results…”