Different nerve-gliding exercises induce different magnitudes of median nerve longitudinal excursion: An in vivo study using dynamic ultrasound imaging

STUDY DESIGN: Controlled laboratory study using single-group, within-subject comparisons. OBJECTIVES: To determine in an in vivo study whether different types of nerve-gliding exercises are associated with different amounts of longitudinal nerve excursion. BACKGROUND: Different types of nerve-gliding exercises have been proposed. It is assumed that different exercises produce different amounts of excursion and strain in the peripheral nervous system. Although this has been confirmed in cadaveric experiments, in vivo studies are lacking. METHODS AND MEASURES: High resolution ultrasound was used to measure longitudinal excursion of the median nerve in the upper arm during 6 different nerve-gliding exercises. Nerve mobilization techniques that involved the elbow and neck were evaluated in 15 asymptomatic volunteers (mean ± SD age, 30 ± 8 years). Nerve longitudinal excursion was calculated using a frame-by-frame cross-correlation analysis. A repeated-measures analysis of variance was used to analyze the data. RESULTS: Different exercises induced different amounts of longitudinal nerve excursion (P-<0001). The "sliding technique"was associated with the largest excursion (mean ± SD, 10.2 ± 2.8 mm; P = .0001). The amount of nerve movement associated with the "tensioning technique" (mean ± SD, 1.8 ± 4.0 mm) was smaller than the nerve excursion induced with individual movements ol the neck or elbow (mean ± SD range, -3.4 ± 0.9 to5.6±2.1mm;P=.0001). CONCLUSION: These findings confirm that different types of neurodynamic techniques have different mechanical effects on the nervous system. Recognition of these differences may assist in the selection ot treatment techniques. Having demonstrated differences in mechanical effects, future research will have to evaluate whether these different techniques are also associated with different Dhvsiolosical and therarjeutic effects.