Table 3. Predictive model coefficients.
| Variable | β | SE | p | Units | Range | TD | Description |
|---|---|---|---|---|---|---|---|
| Intercept | 14.7 | 4.3 | < .01 | S | NA | NA | GMFM-66 linear intercept [7] |
| Age | 0.08 | 0.12 | .50 | Yr. | NA | NA | Child’s age in decimal years (e.g. 10.4 yrs) |
| SCALE | 2.3 | .27 | < .01 | S | 0–10 | 10 | SCALE total limb score bilateral average (0–10) [37] |
| Walk-DMC | 0.24 | 0.04 | < .01 | S | 22–100+* | 100 (10) | Dynamic motor control scaled from normal [43] |
| Strength | 4.5 | 0.85 | < .01 | S | 0–5 | 5 | Multivariate strength scale [35] |
| Spasticity | -0.57 | 0.38 | .13 | S | 0–5 | 0 | Multivariate spasticity scale [33] |
| GDI | 0.17 | 0.04 | < .01 | S | 0–100+* | 100 (10) | Gait deviation index [42] |
| Ankle Dors. Contracture | -0.13 | 0.05 | < .01 | Deg. | > = 0 | 0 | Limitation in achieving > = 21.3° dorsiflexion with knee extended [39–41] |
| Hip Ext. Contracture | -0.17 | 0.08 | .02 | Deg. | > = 0 | 0 | Limitation in achieving > = neutral hip extension [39, 40] |
| Knee Ext. Contracture | -0.11 | 0.07 | .10 | Deg. | > = 0 | 0 | Limitation in achieving > = 4.0° knee extension with hip at neutral [39–41] |
| Hamstrings Contracture | -0.01 | 0.02 | .54 | Deg. | > = 0 | 0 | Limitation in achieving > = 25.6° knee extension with hip flexed to 90° (Popliteal Angle) [39–41] |
| Femoral Anteversion | -0.01 | 0.02 | .44 | Deg. | > = 0 | 0 | Difference from typical anteversion (26.9°) [38, 41] |
| Tibial Torsion | -0.08 | 0.08 | .21 | Deg. | > = 0 | 0 | Non-weightbearing bimalleolar axis difference from typical (16.0°) [39–41] |
S = unitless scale variable defined in description.
NA = not applicable, TD = typically developing value, SE = standard error, p = p-value.
*Both Walk-DMC and GDI are scaled Z-scores that can exceed the mean typical value of 100, additionally Walk-DMC has a theoretical minimum value dependent upon the scaling values.
To obtain subject GMFM66 use equation: GMFM66 = Intercept + ∑iβi ∙ Variablei.