The influence of crank length and cadence on mechanical efficiency in hand cycling

The purpose of this study was to determine the effect of crank length and cadence on mechanical efficiency in hand cycling. Eight wheelchair dependent, high performance athletes completed four 4-min submaximal exercise bouts at a constant power output of 90 W over the different experimental conditions (crank length, pedal rate) using a sports hand bike (Draft, Godmanchester, UK). Two different crank lengths (180 and 220 mm) were tested at two different cadences (70 and 85 rev min−1) using the synchronous mode of cranking. Physiological measures of oxygen uptake VO2, minute ventilation, blood lactate (B[La]), heart rate (HR), rate of perceived exertion (RPE) were recorded, gross (GE) and net (NE) efficiency were calculated. A two-way ANOVA with repeated measures was applied to determine the effects of crank length, cadence and their interaction on these physiological measures. Both GE and NE were significantly higher and VO2 significantly lower for the 180 mm crank (P 0.05). Likewise, no interactions between crank length and pedal rate were found. There was however, a trend observed with HR and B[La] often lower with the 180 mm crank, indicating lower physiological stress. The RPE data supported this finding, with a tendency for lower ratings with the 180 mm crank (9 ± 2 vs. 10 ± 3). The short crank length when used at 85 rev min−1 was found to be the most efficient (GE 21.4 ± 3.1%). In conclusion, crank length has a significant effect on ME in hand cycling. A shorter crank length of 180 mm was found to be more efficient than the 220 mm, regardless of pedal rate during hand cycling

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

<p>Optimizing mobility performance in wheelchair court sports (basketball, rugby and tennis) is dependent on a combination of factors associated with the user, the wheelchair and the interfacing between the two. Substantial research has been attributed to the wheelchair athlete yet very little has focused on the role of the wheelchair and the wheelchair-user combination. This article aims to review relevant scientific literature that has investigated the effects of wheelchair configuration on aspects of mobility performance from an ergonomics perspective. Optimizing performance from an ergonomics perspective requires a multidisciplinary approach. This has resulted in laboratory-based investigations incorporating a combination of physiological and biomechanical analyses to assess the efficiency, health/safety and comfort of various wheelchair configurations. To a lesser extent, field-based testing has also been incorporated to determine the effects of wheelchair configuration on aspects of mobility performance specific to the wheelchair court sports. The available literature has demonstrated that areas of seat positioning, rear wheel camber, wheel size and hand-rim configurations can all influence the ergonomics of wheelchair performance. Certain configurations have been found to elevate the physiological demand of wheelchair propulsion, others have been associated with an increased risk of injury and some have demonstrated favourable performance on court. A consideration of all these factors is required to identify optimal wheelchair configurations. Unfortunately, a wide variety of different methodologies have immerged between studies, many of which are accompanied by limitations, thus making the identification of optimal configurations problematic. When investigating an area of wheelchair configuration, many studies have failed to adequately standardize other areas, which has prevented reliable cause and effect. relationships being established. In addition, a large number of studies have explored the effects of wheelchair configuration in either able-bodied populations or in daily life or racing wheelchairs. As such, the findings are not specific and transferable to athletes competing in the wheelchair court sports. This review presents evidence about the effects of wheelchair configuration on aspects of mobility performance specific to the wheelchair court sports to better inform athletes, coaches and manufacturers about the consequences of their selections. It also provides researchers with guidance on the design of future investigations into areas of wheelchair configuration, which are essential.</p>