Abstract
The purpose of this study was to examine the effect of pelvic stabilization and lower-limb configuration on trunk extension strength and to test whether sex modify these effects. Twenty-two healthy volunteers (11 women and 11 men: SEX factor), age range 20–55 years participated in this study. Two isometric maximal voluntary contractions (MVCs) were performed in extension and the moment was calculated relative to L5/S1, for each of six experimental conditions. Two different positions were tested (POSITION factor): I) seated position (knees at 90°) and II) semi-sitting position (knees at 45°). In each POSITION, three pelvic stabilization conditions were tested(STABILIZATION factor): (1) unrestrained (control condition), (2) partially restrained (posteriorly) and (3) totally restrained (posteriorly and anteriorly). No significant main effects (p> 0.05) and no double and triple(SEX × STABILIZATION × POSITION) interaction reached statistical significance. Consequently, maximal trunk extension moment can be achieved with the use of various stabilization and positioning modalities, at least when the same apparatus allows such flexibility, and this as much in women as in men subjects. These results have implications for the assessment of trunk extension strength during pre- and post-training regiments during a rehabilitation program for strengthening of back muscles in patients with low back pain.