Skip to main content
. Author manuscript; available in PMC: 2010 Aug 25.
Published in final edited form as: J Biomech. 2009 Jun 10;42(12):1903–1908. doi: 10.1016/j.jbiomech.2009.05.009

Table 3.

Group mean ± standard deviation of recovery step length (Xstep) at recovery foot touchdown, the stride length Xstride of recovery limb, slip distance (Xslip) and velocity of base of support (BOS) (VBOS, L-TD, pre) at the instant immediately prior to recovery touchdown, maximum slip distance (Xslip, max), and peak slip velocity of BOS, (VBOS, max) for fall and recovery, and for slip and non slip (unperturbed) trials during both gait and sit-to-stand (STS) tasks.

Tasks Variables Slip Non Slip
Gait
  
 Fall (n = 9)
 Recovery (n = 44)
 (n = 53)
Xstep (m) −0.446 ± 0.122 −0.520 ± 0.134 0.646 ± 0.074
Xstride (m) 0.427 ± 0.190 0.418 ± 0.175 1.301 ± 0.127
Xslip (m) 0.281 ± 0.066a 0.221 ± 0.066 0.015 ± 0.009
VBOS, L-TD, pre (m/s) 1.750 ± 0.270b 1.391 ± 0.340 0.001 ± 0.004
Xslip, max (m) 0.781 ± 0.333b 0.560 ± 0.293 0.017 ± 0.009
 
 VBOS, max (m/s)
 2.513 ± 0.280c
 1.982 ± 0.449
 0.001 ± 0.007
STS
  
 Fall (n = 9)
 Recovery (n = 32)
 (n = 41)
Xstep (m) −0.207 ± 0.112e −0.243 ± 0.099e
Xstride (m) −0.127 ± 0.100e −0.160 ± 0.103e
Xslip (m) 0.256 ± 0.008a 0.240 ± 0.037Δ 0.011 ± 0.006
VBOS, L-TD, pre (m/s) −0.038 ± 0.107d,e 0.367 ± 0.580e 0.001 ± 0.003
Xslip, max (m) 0.258 ± 0.008e 0.260 ± 0.012Δe 0.013 ± 0.007
VBOS, max (m/s) 1.305 ± 0.256e 1.331 ± 0.304e 0.001 ± 0.004
a

p < 0.05 vs. recovery (main effect of slip outcome)

b

p < 0.01 vs. gait-slip recovery (interaction of task and slip outcome)

c

p < 0.001 vs. gait-slip recovery (interaction of task and slip outcome)

d

p< 0.001 vs. STS-slip recovery (interaction of task and slip outcome)

e

p < 0.001 vs. gait-slip (main effect of task).

Δ

Travel displacement of slider may exceed 0.24 m, which was the design specification, due to the deformation of the shock absorber from the impact during an actual slip trial.