TY - JOUR T1 - Comparison of Erector Spine Muscles Activity Patterns in Lowering between Subjects with and without History of Low Back Pain TT - مقایسه الگوی فعالیت عضله راست‌کننده ستون‌فقرات در حین عمل پایین گذاشتن بار قبل و بعد از حفظ طولانی مدت وضعیت فلکسیون کمر در افراد با سابقه کمردرد و افراد سالم JF - USWR JO - USWR VL - 10 IS - 2 UR - http://rehabilitationj.uswr.ac.ir/article-1-326-en.html Y1 - 2009 SP - 0 EP - 0 KW - Flexion relaxation phenomenon KW - Lowering KW - Low back pain KW - Erector soine muscle N2 - Objective: The purpose of this research was to compare the erector spine flexion relaxation phenomenon between subjects with and without history of Low back pain. Materials & Methods: In this Quasi-experimental study, 15 persons with history of low back pain were selected simply from convenient samples and 15 healthy persons were selected by matching method. Surface Electromyography and Electrogoniometery were used. Subjects performed lifting and lowering tasks with load and without load as randomly, then Prolonged Static lumbar flexion were maintained for 7 minutes, then lifting and lowering tasks repeated. Erector spine Flexion relaxation phenomenon before and after prolonged static lumbar flexion (position), with and without load, in two groups were compared by 3 ways mixed ANOVA. Results: The interactions between Load * position (P=0.120) and group* load (P=0.365) were insignificant, but interaction between group * position were significant (P M3 ER -