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Table 8 Multinomial logistic parameter estimations, with standard errors in brackets

From: Manual wheelchair downhill stability: an analysis of factors affecting tip probability

  Forward tip vs Stop Backward tip vs Stop Rolled vs Stop Backward vs Forward tip Rolled vs Forward tip Rolled vs Backward tip
Bump height (cm) −0.127 (0.292) −6.088*** (0.467) −7.612*** (0.473) −5.962*** (0.439) −7.486*** (0.448) −1.524*** (0.148)
Speed (km/hr) 2.311*** (0.235) 2.684*** (0.244) 2.851*** (0.244) 0.373*** (0.041) 0.540*** (0.040) 0.167*** (0.022)
Rear axle position (cm) 0.170*** (0.038) 0.547*** (0.049) 0.128** (0.042) 0.377*** (0.035) −0.042 (0.024) −0.419*** (0.032)
Backrest angle (°) −0.119*** (0.035) 0.258*** (0.042) 0.042 (0.038) 0.377*** (0.031) 0.160*** (0.026) −0.216*** (0.022)
Slope (°) 0.532*** (0.065) 0.439*** (0.068) 0.493*** (0.067) −0.094** (0.034) −0.039 (0.030) 0.054* (0.025)
User position (cm) 0.006 (0.073) −0.375*** (0.084) −0.170* (0.080) − 0.382*** (0.054) −0.176*** (0.047) 0.205*** (0.039)
Seat angle (°) −0.059 (0.035) 0.086* (0.041) 0.029 (0.039) 0.145*** (0.026) 0.087*** (0.023) −0.058** (0.019)
User mass (kg) 0.025** (0.011) −0.010 (0.012) 0.005 (0.012) −0.035*** (0.008) −0.020** (0.007) 0.015** (0.006)
  1. The first three columns use the ‘stop’ condition as the reference category, the next two use ‘forward tip’ as the reference category, and the final column uses ‘backward tip’ as the reference. In that way comparisons were made between all categories. Bump height and wheelchair speed were the most influential parameters, with the rear axle position and backrest angle having the greatest effect of the parameters directly relating to wheelchair configuration (*p < 0.05, **p < 0.02, ***p < 0.001)