Table 2.
Extracted factors from principal components analysis, including the relevant discrete biomechanical variables, loading weight, descriptive data, and factor descriptiona
| Factor | Variables | Overall Mean ± SD | Loading Weight | Factor Description |
|---|---|---|---|---|
| 1 | HFpk | 43.6 ± 13.9° | 0.180 | More hip flexion motion and energy absorption |
| HFex | 35.2 ± 10.7° | 0.270 | ||
| Hwa | 0.01 ± 0.01, J × BW-1 × Ht-1 × 10-3 | 0.431 | ||
| 2 | Hfin | 8.5 ± 7.7° | 0.188 | Greater initial hip flexion and hip loading |
| HFmom | 0.10 ± 0.03, Nm × BW | 0.219 | ||
| Hk | 3.1 ± 1.5, Nm × BW | 0.347 | ||
| 3 | KFpk | 87.1 ± 10.8° | 0.235 | More knee and ankle flexion with more knee energy absorption |
| KFex | 75.0 ± 10.6° | 0.288 | ||
| AFpk | 17.2 ± 5.1° | 0.332 | ||
| Kwa | 0.09 ± 0.02, J × BW-1 × Ht-1 | 0.220 | ||
| 4 | AKSF | 0.72 ± 0.12, BW | 0.343 | Greater knee loading |
| GRF | 1.51 ± 0.23, BW | 0.256 | ||
| KFmom | 0.11 ± 0.02, Nm × BW-1 × Ht-1 | 0.432 | ||
| Kwa | 0.09 ± 0.02, J × BW-1 × Ht-1 | 0.232 | ||
| Kk | 1.6 ± 0.4, Nm × BW-1 × Ht-1 × deg-1 | 0.386 | ||
| 5 | Afin | 42.1 ± 7.0° | 0.433 | More flexed ankle position |
| AFex | 59.3 ± 6.9° | –0.393 | ||
| 6 | AKSF | 0.72 ± 0.12, BW | 0.222 | Greater ankle loading and knee shear |
| AFmom | 0.06 ± 0.02, Nm × BW-1 × Ht-1 | 0.323 | ||
| Awa | –0.03 ± 0.01, J × BW-1 × Ht-1 | 0.253 | ||
| Ak | 1.1 ± 0.4, Nm × BW-1 × Ht-1 × deg-1 × 10-3 | 0.289 | ||
| 7 | HERin | 1.6 ± 5.4° | 0.264 | More initial hip external rotation, knee valgus, and internal rotation with less transverse plane knee motion |
| KVALin | –0.4 ± 5.1° | 0.216 | ||
| KVALpk | 1.8 ± 8.1° | 0.213 | ||
| KERin | 10.2 ± 8.6 | –0.346 | ||
| KERpk | 11.4 ± 8.2° | –0.330 | ||
| KIRex | –19.5 ± 8.9° | 0.282 | ||
| 8 | HADex | −1.6 ± 2.8° | −0.183 | More relative hip adduction and knee valgus motion with less relative hip internal rotation |
| HIRpk | 5.8 ± 7.8° | 0.260 | ||
| HIRex | –7.4 ± 5.8° | 0.264 | ||
| KVARpk | –12.6 ± 9.6° | 0.236 | ||
| KVARex | –12.3 ± 8.2° | 0.324 | ||
| KVALex | 2.1 ± 3.8° | 0.208 | ||
| 9 | KIRpk | −9.3 ± 8.3° | −0.299 | More knee internal rotation motion |
| KIRex | –19.5 ± 8.9° | –0.229 | ||
| 10 | KERex | 1.2 ± 2.0° | 0.694 | More knee external rotation motion |
| 11 | HADmom | −0.03 ± 0.02, Nm × BW-1 × Ht-1 | 0.315 | Less frontal and transverse plane hip and knee loading |
| HERmom | 0.01 ± 0.001, Nm × BW-1 × Ht-1 | –0.225 | ||
| KVARmom | –0.02 ± 0.01, Nm × BW-1 × Ht-1 | 0.411 | ||
| KIRmom | –0.01 ± 0.01, Nm × BW-1 × Ht-1 | 0.251 |
H, hip; K, knee; A, ankle; AD, adduction (–); VAL, valgus (+); VAR, varus (–); ER, external rotation (+); IR, internal rotation (–); F, flexion; in, initial angle; pk, peak angle; ex, excursion; mom, moment; k, stiffness; wa, work absorption; AKSF, anterior knee shear force; GRF, ground reaction force.
a
All sagittal plane flexion angles, extensor moments, stiffness, and work absorption values are positive (+).