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Table 3 Group mean (± SD) stance phase moments and power integrals at distal end of prosthetic shank ( pros-end ) when using rigid ( rig F) and hydraulic ( hy A-F) ankle-foot devices

From: Walking speed related joint kinetic alterations in trans-tibial amputees: impact of hydraulic 'ankle’ damping

  Speed Normalised Absolute
  hyA-F rigF p value hyA-F rigF p value
  Nm.s/(kg.m/s)   Nm.s.kg-1  
External early-stance 'plantarflexion’ moment impulse -0.06 (0.03) -0.06 (0.03) 0.36 (foot) -0.05 (0.03) -0.06 (0.03) 0.54 (foot)
-0.05 (0.02) -0.06 (0.02) 0.13 (speed) -0.07 (0.03) -0.07 (0.02) 0.028 (speed)
-0.05 (0.02) -0.05 (0.02) 0.81 (interact) -0.06 (0.03) -0.07 (0.02) 0.058 (interact)
External mid/late stance 'dorsiflexion’ moment impulse +0.43 (0.14) +0.46 (0.13) 0.30 (foot) +0.40 (0.13) +0.42 (0.07) 0.79 (foot)
+0.31 (0.12) +0.34 (0.10) <0.001 (speed) +0.36 (0.09) +0.36 (0.06) <0.001 (speed)
+0.27 (0.11) +0.27 (0.08) 0.12 (interact) +0.35 (0.09) +0.34 (0.05) 0.12 (interact)
  J/(kg.m/s)   J.kg-1  
Negative work – early stance -0.02 (0.01) -0.01 (0.01) 0.009 (foot) -0.02 (0.01) -0.02 (0.01) 0.011 (foot)
-0.03 (0.01) -0.02 (0.01) 0.017 (speed) -0.03 (0.01) -0.02 (0.01) 0.005 (speed)
-0.02 (0.01) -0.02 (0.01) 0.55 (interact) -0.03 (0.01) -0.03 (0.01) 0.21 (interact)
Positive work - early stance +0.003 (0.00) +0.003 (0.00) < 0.001 (foot) +0.004 (0.00) +0.004 (0.00) 0.011 (foot)
+0.003 (0.00) +0.006 (0.00) 0.007 (speed) +0.003 (0.00) +0.007 (0.00) < 0.001 (speed)
+0.008 (0.00) +0.010 (0.00) 0.09 (interact) +0.012 (0.00) +0.014 (0.01) 0.09 (interact)
Negative work - mid-stance -0.11 (0.05) -0.10 (0.05) 0.08 (foot) -0.15 (0.04) -0.12 (0.04) 0.043 (foot)
-0.14 (0.07) -0.13 (0.04) 0.36 (speed) -0.16 (0.05) -0.13 (0.03) 0.39 (speed)
-0.11 (0.04) -0.11 (0.04) 0.48 (interact) -0.14 (0.04) -0.14 (0.03) 0.13 (interact)
Positive work - late stance +0.07 (0.03) +0.08 (0.03) < 0.001 (foot) +0.09 (0.03) +0.11 (0.03) < 0.001 (foot)
+0.08 (0.03) +0.11 (0.03) 0.47 (speed) +0.09 (0.03) +0.12 (0.03) 0.47 (speed)
+0.06 (0.03) +0.09 (0.02) 0.024 (interact) +0.09 (0.03) +0.12 (0.04) 0.027 (interact)
Total work 0.20 (0.08) 0.19 (0.07) 0.22 (foot) 0.19 (0.06) 0.17 (0.05) 0.84 (foot)
0.25 (0.09) 0.26 (0.08) 0.20 (speed 0.29 (0.07) 0.28 (0.06) 0.023 (speed)
0.20 (0.06) 0.22 (0.06) 0.09 (interact) 0.29 (0.12) 0.31 (0.11) 0.10 (interact)
Energy dissipated (negative + positive work) 0.06 (0.04) 0.03 (0.03) 0.001 (foot) 0.08 (0.03) 0.03 (0.04) < 0.001 (foot)
0.08 (0.06) 0.03 (0.02) 0.71 (speed) 0.10 (0.05) 0.03 (0.03) 0.046 (speed)
0.07 (0.04) 0.03 (0.02) 0.43 (interact) 0.08 (0.04) 0.03 (0.03) 0.25 (interact)
Time of moment ’flip’ (% stance) 28.5 (4.9) 32.9 (3.8) 0.029 (foot)  
30.8 (5.3) 36.1 (5.9) 0.25 (speed)  
28.4 (4.8) 34.0 (4.1) 0.31 (interact)  
  1. Results are listed downwards - slow, customary speed and fast. Values normalised to walking speed are in the left-hand columns and absolute values in the right-hand columns. Statistically significant differences are in bold.