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Table 1 Propulsion variables

From: Variability in bimanual wheelchair propulsion: consistency of two instrumented wheels during handrim wheelchair propulsion on a motor driven treadmill

Variable: Description: Equation:
Push time (s) Time from the start of positive torque to the stop of positive torque for an individual push. tend(i) - tstart(i)
Cycle time (s) Time from the start of positive torque to the next start of positive torque. tend(i) − tend(i − 1)
Contact angle (rad) Angle at the end of a push minus the angle at the start. Øend(i) − Østart(i)
Fpeak (N) 3d peak force during the push phase Maxstart : end(Fx2 + Fy2 + Fz2)0.5
Mean Power/push (W) The mean power during the push phase. Meanstart : end(Tz • Δ Ø)
Work/push (J) The power integrated over the duration of the push. start : end(Tz • Δ Ø)
Frequency (push/min) Pushes per minute. Npushes/Δ t
Mean power/minute (W) The mean total (unilateral) power (Tz*Angular velocity) during a complete series of cycles in a minute multiplied by 2. 2 • (∑start(i) : start(n)(Tz • Δ Ø))
  1. Abbrevations: t, time(s); start(i), start of the current push (sample); end(i), end of the current push (sample); Ø, angle (rad); Fx, Fy and Fz, force components (N); Tz, torque around wheel axle (Nm).