Table 3.
Internal disc loads at disc mid-heights and muscle forces (on each side) at different levels for the optimal posture with T12 (minimum sum of muscle forces, no abdominal co-activity) (IC iliocostalis, LG longissimus, MF multifidus muscles)
| Level | P=0 N | P=200 N | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| -- | Held on sides | Held in front | ||||||||||
| *Passive segmental load | Muscle force | *Passive segmental load | Muscle force | *Passive segmental load | Muscle force | |||||||
| Comp (N) | Shear (N) |
Moment (Nm) |
Comp | Shear | Moment | Comp | Shear | Moment | ||||
| (N) | (N) | (N) | (Nm) | (N) | (N) | (N) | (Nm) | (N) | ||||
| T12 | 301 | −70 | −8.0 | 5 (IC) | 506 | −107 | −9.7 | 12 (IC) | 537 | −206 | −15.0 | 73 (IC) |
| L1 | 323 | −77 | −5.5 | 5 (MF) | 533 | −119 | −5.3 | 12 (MF) | 549 | −227 | −7.4 | 2 (MF) |
| L2 | 344 | −88 | −2.6 | 6 (LG) | 556 | −126 | −0.9 | 6 (LG) | 566 | −233 | 1.0 | -- |
| L3 | 376 | −23 | −0.1 | 4 (LG) | 594 | −16 | 1.2 | 7 (LG) | 622 | −110 | 5.9 | 1 (LG) |
| L4 | 400 | 7 | 0.4 | 3 (MF) | 625 | 59 | 2.5 | 16 (MF) | 662 | −2 | 10.8 | 14 (MF) |
| L5 | 404 | 147 | −0.8 | 9 (MF) | 599 | 273 | −1.3 | 12 (MF) | 638 | 268 | 8.2 | 10 (MF) |
*Shear force: positive in anterior direction; Moment: positive in extension direction