. Author manuscript; available in PMC: 2011 Sep 1.

Published in final edited form as: Spinal Cord. 2010 Nov 2;49(3):457–462. doi: 10.1038/sc.2010.149

Table 1.

Propulsion variables

Variable	Description [Units]	Equation
Speed	Mean speed during the stroke, [m/s]	(θ_stroke/180) ·π·D/t_stroke
Cadence	Push frequency, [pushes/min]	60/t_stroke
Contact Angle	Angle through which wheel rotates when hand is on handrim, [degrees]	wheel angle at recovery start − wheel angle at push start
Power Output	Power generated per stroke, [Watts]	Σ(M_axleΔθπ/180)/t_stroke
Peak Force	Maximum total force applied to the handrim during the stroke, [Newtons]	max(F_tot), where F_tot = √(F_x² + F_y² + F_z²)
Average Force	Average total force applied to the handrim during the stroke, [Newtons]	mean (F_tot)
Peak Moment	Maximum moment about the axle during the stroke, [Newton-meters]	max(M_axle)

D = wheel diameter [m], θ = wheel angle [degrees], θ_stroke = angle through which the wheel rotates during the stroke [degrees], t_stroke = time to complete the stroke [s], and Δθ = point-to-point change in angle [degrees].