Mechanosensitivity of the lower extremity nervous system during straight-leg raise neurodynamic testing in healthy individuals

Cross-sectional, observational study. To explore how ankle position affects lower extremity neurodynamic testing. Upper extremity limb movements that increase neural loading create a protective muscle action of the upper trapezius, resulting in shoulder girdle elevation during neurodynamic testing. A similar mechanism has been suggested in the lower extremities. Twenty healthy subjects without low back pain participated in this study. Hip flexion angle and surface electromyographic measures were taken and compared at the onset of symptoms (P1) and at the point of maximally tolerated symptoms (P2) during straight-leg raise tests performed with ankle dorsiflexion (DF-SLR) and plantar flexion (PF-SLR). Hip flexion was reduced during DF-SLR by a mean +/- SD of 5.5 degrees +/- 6.6 degrees at P1 (P = .001) and 10.1 degrees +/- 9.7 degrees at P2 (P