Biomechanics in Handcycling

Abstract

PURPOSE: Handbike as a wheelchair sport has gained increased popularity in Germany. During the last 5 years race performance has increased enormously due to a systematic training and developments concerning the handbike itself. In comparison to wheelchair propulsion handbiking has a higher mechanical efficiency (ME). The aim of this study was to examine the effect of three different grip positions on the ME in handbiking. METHODS: Fifteen male and six female participants performed three different stage tests until exhaustion sitting in a race handbike connected to an ergo meter. All participants were able bodied persons with a good training status of the upper extremity. The angel between the grip and the crank was set by 90° (horizontal = H), 0° (vertical = V) and 10° (diagonal, common way of cranking = D). The initial load was 20 watts increased by 20 watts each five minutes. Expired air was collected continuously, blood samples to determine lactate concentrations were taken at the last 30 seconds of each stage. Heart rate was monitored continuously, RPE-scale was used. RESULTS: The relative maximum functional performance (watts/kg), maximum heart rate (bpm) the associated lactate concentrations (mmol/l) and maximum oxygen uptake per kilogram body weight (ml/kg) for the different grip positions were: Horizontal 1.43 ± 0.21 watts/kg, 170.14 ±12.81 bpm, 9.54 ±1.93 mmol/l, 30.86 ±4.57ml/kg; Vertical 1.38 ± 0.20 watts/kg, 171.81 ± 13.87 bpm, 9.91 ± 2.29 mmol/l, 29.75 ± 5.13 ml/kg; Diagonal 1.40 ±0.22 watts/kg, 169.19 ±13.31 bpm, 9.34 ± 2.36 mmol/l, 29.39 ±4.70 ml/kg;. In all grip positions the RPE values were 20 meaning a very heavy load. No statistically significant differences could be found between the mentioned physical reactions. CONCLUSIONS: In opposite to the expectations there were no differences between three different grip positions (horizontal, vertical, diagonal) in handbiking at maximum load. The mechanical efficiency during a stage test until exhaustion showed no differences, so at this knowledge no grip position could be recommended for athletes. In further studies it has to be proven whether these findings are negotiable to prolonged work load durations and to athletes with a spinal cord injury. In addition it would be of particular interest to combine the test setting with EMG registrations.