Horizontal crank position affects economy and upper limb kinematics of recumbent handcyclists

Purpose: To determine the effects of horizontal crank position on economy and upper limb kinematics in recumbent handcycling. Methods: Fifteen trained handcyclists performed trials at 50% and 70% of their peak aerobic power output (POPeak), determined during a maximal ramp test, in each horizontal crank position. Four horizontal crank positions, 94%, 97%, 100% and 103% of arm length, were investigated. Horizontal crank positions were defined as the distance between the acromion angle to the centre of the handgrip, while the crank arm was parallel to the floor and pointing away from the participant. Economy and upper limb kinematics were calculated during the final minute of each three-minute trial. Results: Horizontal crank position significantly affected handcycling economy at 70% POPeak (P < 0.01) but not at 50% POPeak (P = 0.44). The 97% horizontal crank position (16.0 (1.5) mL·min-1·W- 1 ) was significantly more economical than the 94% (16.7 (1.9) mL·min-1·W-1 ) (P = 0.04) and 103% (16.6 (1.7) mL·min-1·W-1 ) (P < 0.01) positions. The 100 % horizontal crank position (16.2 (1.7) mL·min-1·W-1) was significantly more economical than the 103% position (P < 0.01). Statistical parametric mapping indicated that an increase in horizontal crank position, from 94% to 103%, caused a significant increase in elbow extension, shoulder flexion, adduction, internal rotation, scapular internal rotation, wrist flexion, clavicle depression and clavicle protraction between 0 – 50 % (0° - 180°) of the cycle (P < 0.05). Conclusion: Positioning the cranks at 97% to 100% of the athletes’ arm length improved handcycling economy at 70% POPeak as, potentially, the musculature surrounding the joints of the upper limb were in a more favourable position to produce force economically.