Table 2. Mixed effects models for physical performance and self-reported measures (intention to treat analysis).
| MIp group | Control group | LMEM time effect |
time*group effect |
t value (p value) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| PRE | POST | Δ (%) | PRE | POST | Δ (%) | Parameter Estimate (SE) | t value (p value) | Parameter Estimate (SE) | ||
| Physical function | ||||||||||
| Maximal isometric extension strength of the operated knee (Nm) | 117.3 ± 48.6 | 68.1 ± 32.3 | -41.9 | 134.3 ± 47.1 | 43.3 ± 25.1 | -67.8 | 101.2 (11.7) | 8.637 (<0.001) | -36.0 (16.6) | -2.173 (0.037) |
| 30s Chair sit to stand (n) | 9.9 ± 2.8 | 9.2 ± 2.6 | -7.4 | 10.8 ± 3.3 | 5.8 ± 2.7 | -46.7 | 5.0 (0.8) | 6.608 (<0.001) | -4.1 (1.1) | -3.833 (<0.001) |
| Self-selected gait speed (m/s) | 1.1 ± 0.2 | 1.1 ± 0.1 | 3.5 | 1.2 ± 0.1 | 0.9 ± 0.2 | -25.0 | 0.3 (0.1) | 5.382 (<0.001) | -0.3 (0.1) | -4.301 (<0.001) |
| Self-selected gait speed DT (m/s) | 1.0 ± 0.2 | 1.0 ± 0.2 | 2.8 | 1.1 ± 0.2 | 0.9 ± 0.2 | -22.6 | 0.3 (0.1) | 4.821 (<0.001) | -0.3 (0.1) | -3.709 (0.001) |
| Brisk-paced gait speed (m/s) | 1.5 ± 0.2 | 1.4 ± 0.2 | -3.3 | 1.4 ± 0.2 | 1.0 ± 0.3 | -28.2 | 0.4 (0.1) | 5.052 (<0.001) | -0.4 (0.1) | -3.210 (0.003) |
| Brisk-paced gait speed DT (m/s) | 1.2 ± 0.2 | 1.2 ± 0.2 | -3.0 | 1.4 ± 0.2 | 1.0 ± 0.3 | -27.6 | 0.4 (0.1) | 5.192 (<0.001) | -0.3 (0.1) | -3.328 (0.003) |
| Spatiotemporal gait parameters during self-selected pace gait | ||||||||||
| Single support period (s) | 0.4 ± 0.0 | 0.4 ± 0.1 | -3.5 | 0.4 ± 0.0 | 0.4 ± 0.0 | 7.5 | -0.03 (0.1) | -3.020 (0.005) | 0.05 (0.02) | 3.264 (0.003) |
| Double support period (s) | 0.3 ± 0.1 | 0.3 ± 0.1 | -7.7 | 0.3 ± 0.0 | 0.4 ± 0.1 | 35.4 | -0.11 (0.02) | -4.614 (<0.001) | 0.13 (0.03) | 4.084 (<0.001) |
| Stride length (cm) | 126.7 ± 13.8 | 126.4 ± 12.0 | -0.2 | 129.7 ± 14.2 | 111.0 ± 17.2 | -14.5 | 17.5 (2.9) | 6.010 (<0.001) | -16.3 (4.1) | -3.974 (<0.001) |
| Cadence (steps/min) | 101.7 ± 11.2 | 105.9 ± 8.5 | 4.1 | 108.6 ± 6.5 | 94.8 ± 7.9 | -12.7 | 13.7 (3.2) | 4.275 (<0.001) | -17.8 (4.5) | -3.928 (<0.001) |
| Self-reported physical function and motor imagery ability | ||||||||||
| LEFS (points) | 33.1 ± 7.0 | 34.1 ± 6.8 | 3.1 | 31.5 ± 8.4 | 26.2 ± 5.6 | -16.6 | 5.1 (2.2) | 2.298 (0.030) | -6.4 (3.1) | -2.027 (0.053) |
| Kineasthetic imagery ability | 5.6 ± 0.8 | 5.6 ± 0.8 | 0.0 | 5.4 ± 1.5 | 5.1 ± 1.0 | -5.9 | 0.5 (0.1) | 3.534 (0.002) | -0.5 (0.2) | -2.675 (0.013) |
| Internal visual imagery ability | 5.6 ± 1.3 | 5.7 ± 0.8 | 2.8 | 5.9 ± 1.0 | 5.4 ± 0.6 | -8.7 | 0.5 (0.2) | 2.309 (0.028) | -0.7 (0.3) | -2.207 (0.035) |
| External visual imagery ability | 5.9 ± 1.1 | 5.8 ± 0.8 | -0.6 | 5.9 ± 0.8 | 5.8 ± 0.5 | -2.0 | 0.1 (0.2) | 0.558 (0.581) | -0.1 (0.3) | -0.488 (0.629) |
| Cognitive performance | ||||||||||
| Baseline (number of correct answers) | 24.8 ± 9.4 | 29.5±8.9 | 19.1 | 24.0 ± 6.9 | 27.5±10.9 | 14.6 | -4.6 (1.8) | -2.554 (0.017) | 0.5 (2.5) | 0.212 (0.834) |
| Serial 3s during self-selected gait speed (number of correct answers) | 42.4 ± 14.4 | 50.3±17.7 | 18.8 | 40.7 ± 17.6 | 42.5±18.4 | 4.4 | -5.2 (2.7) | -1.923 (0.066) | -1.2 (3.8) | -0.320 (0.752) |
| Serial 3s during brisk-paced gait (number of correct answers) | 46.8 ± 16.3 | 53.8±19.1 | 15.0 | 45.5 ± 19.3 | 38.4±13.0 | -15.7 | -0.7 (3.3) | -0.226 (0.823) | -3.7 (4.4) | -0.826 (0.418) |
Note: Data are presented as mean ± SD; Bolded values represents a significant effect
MIp motor imagery practice group; LEFS Lower extremity functional score questionnaire; Δ (%)–percent changes between initial and final measurement; SE–standard error; LMEM–Linear mixed effects models