Table 7. Group differences determined with a Mann Whitney U test (median, interquartile range and p-value).
| CP | TD | Mann-Whitney U | |
|---|---|---|---|
| Self-selected walking speed | Median (25%-75%) | ||
| Number of included gait cycles | 4.0 (3.0–4.5) | 5.0 (3.5–6.0) | |
| Kinematics | |||
| Maximal hip extension angle during stance (deg) | 4.8 (-3.2–8.4) | -9.2 (-11.7 –-0.7) | p < 0.0001* |
| Knee angle at initial contact (deg) | 25.5 (16.4–32.5) | 6.8 (3.4–8.9) | p < 0.0001* |
| Maximal knee flexion angle during stance (deg) | 37.0 (32.3–41.3) | 36.7 (1.4–39.3) | p = 0.357 |
| Maximal knee flexion angle during swing (deg) | 63.1 (48.6–66.4) | 64.8 (59.9–67.6) | p = 0.017 |
| Timing maximal knee flexion in swing (% GC) | 73.2 (70.2–77.8) | 70.9 (70.2–71.4) | p = 0.155 |
| Ankle angle at initial contact (deg) | -0.1 (-2.4–3.5) | -1.4 (-4.7–0.1) | p = 0.106 |
| Maximal dorsiflexion angle during swing (deg) | 4.7 (0.2–8.1) | 3.6 (1.2–5.4) | p = 0.663 |
| Kinetics | |||
| Maximal knee extension torque (Nm/kg) | 0.47 (0.41–0.77) | 0.62 (0.51–0.69) | p = 0.695 |
| Maximal knee flexion torque (Nm/kg) | 0.19 (-0.07–0.34) | 0.20 (0.12–0.27) | p = 0.782 |
| Ankle torque during loading response (Nm/kg) | -0.01 (-0.03 –-0.01) | -0.13 (-0.16 –-0.10) | p < 0.0001* |
| Maximal plantar flexion torque (Nm/kg) | 1.08 (0.95–1.21) | 1.38 (1.29–1.51) | p < 0.0001* |
| Maximal power generation at the ankle (W/kg) | 2.33 (1.58–2.71) | 4.44 (3.96–4.80) | p < 0.0001* |
| GDI | 78.99 (73.11–87.30) | ||
| GDI-kinetic | 86.55 (77.71–93.72) | ||
| Non-dimensional walking speed | 0.39 (0.36–0.43) | 0.46 (0.41–0.52) | p < 0.0001* |
| Walking as fast as possible | |||
| Number of included gait cycles | 3.0 (2.0–3.5) | 5.0 (3.0–5.0) | |
| Kinematics | |||
| Maximal hip extension angle during stance (deg) | 6.0 (-0.5–7.3) | -10.1 (-14.6 –-2.7) | p < 0.0001* |
| Knee angle at initial contact (deg) | 26.6 (18.1–35.1) | 11.2 (7.1–14.8) | p < 0.0001* |
| Maximal knee flexion angle during stance (deg) | 34.2 (27.5–41.2) | 36.0 (33.4–39.7) | p = 0.469 |
| Maximal knee flexion angle during swing (deg) | 62.5 (50.0–66.9) | 65.8 (62.0–68.473) | p = 0.071 |
| Timing maximal knee flexion in swing (% GC) | 73.2 (69.4–77.9) | 69.2 (68.0–69.9) | p = 0.006 |
| Ankle angle at initial contact (deg) | -1.4 (-3.8–2.8) | 0.2 (-3.3–2.1) | p = 0.542 |
| Maximal dorsiflexion angle during swing (deg) | 5.5 (0.7–9.2) | 6.6 (4.4–7.7) | p = 0.326 |
| Kinetics | |||
| Maximal knee extension torque (Nm/kg) | 0.73 (0.53–1.01) | 1.02 (0.63–1.15) | p = 0.326 |
| Maximal knee flexion torque (Nm/kg) | 0.50 (0.15–0.78) | 0.29 (0.22–0.34) | p = 0.082 |
| Ankle torque during loading response (Nm/kg) | -0.01 (-0.03–0.00) | -0.20 (-0.25 –-0.14) | p < 0.0001* |
| Maximal plantar flexion torque (Nm/kg) | 1.03 (0.86–1.19) | 1.49 (1.34–1.59) | p < 0.0001* |
| Maximal power generation at the ankle (W/kg) | 2.38 (1.97–3.07) | 5.52 (4.59–6.02) | p < 0.0001* |
| GDI | 69.47 (62.88–79.62) | ||
| GDI-kinetic | 65.35 (61.05–71.80) | ||
| Non-dimensional walking speed | 0.55 (0.48–0.64) | 0.67 (0.62–0.72) | p = 0.002* |
| MVICS | |||
| Knee extension MVIC (Nm/kg) | 0.48 (0.28–0.64) | 1.27 (1.13–1.63) | p < 0.0001* |
| Knee flexion MVIC (Nm/kg) | 0.43 (0.18–0.52) | 0.87 (0.73–1.10) | p < 0.0001* |
| Dorsiflexion MVIC (Nm/kg) | 0.08 (0.05–0.11) | 0.27 (0.24–0.30) | p < 0.0001* |
| Plantar flexion MVIC (Nm/kg) | 0.34 (0.22–0.38) | 0.54 (0.39–0.81) | p < 0.0001* |
| Plantar flexion RFD (N/s) | 182.40 (142.69–258.70) | 661.95 (338.69–813.41) | p < 0.0001* |
Abbreviations in alphabetic order: CP = cerebral palsy; deg = degrees; GDI = gait deviation index; MVIC = maximal voluntary isometric contraction; N/s = Newtons per second; Nm/kg = Newton meter per kilogram bodyweight; RFD = rate of force development; TD = typical developing; W/kg = Watts per kilogram bodyweight; % GC = percentage gait cycle. NB: All net joint torques are reported as absolute values, with exception of ankle torque during loading response (negative values represent dorsiflexion torque, positive values represent plantar flexion torque). The minimal number of included gait cycles was one in both groups (CP and TD) was one for both walking speeds.