Kinematic analysis of handbike propulsion in various gear ratios: Implications for joint pain

Background. Though considered more efficient and less constraining than the hand-rim wheelchair, the handbike has rarely been studied especially as regards its kinematic parameters. The hypothesis of this investigation is that the range of upper extremity motions are risk factors for joint pain during handbiking as is the case during hand-rim wheelchair propulsion. This paper aims to study handbike propulsion in maximal sprint conditions in order to determine potential risk factors for joint pain.Methods. Eight able-bodied participants with no experience in handbike propulsion performed three sprints of 8 s each using three gear ratios in a handbike mounted on a home-trainer. The mean velocity per arm cycle, the cycle frequency, the angular parameters for the upper extremities were calculated, as well as the corresponding angular accelerations, with the help of a 3D movement analysis.Findings. An increase in gear ratio (22/21, 32/21, and 44/21) significantly increases the maximal velocity, the flexion/extension of the trunk, as well as the adduction/abduction of the elbow, while it reduces the frequency of movements and the flexion/extension angular accelerations of the shoulder and the elbow. Regardless of what gear ratio is used, maximal angular amplitudes of the upper extremities are comparable to the values obtained with a hand-rim wheelchair.Interpretation. The high amplitudes and fast angular joint accelerations of the upper extremity found in this study are near or superior to the ergonomic recommendations generally advised. These considerations could be taken into account to prevent overuse injuries.