the test-retest reliability of the onset of core and vasti electromyographic activity while ascending and descending stairs in healthy controls and patellofemoral pain patients

abstractbackgroundentity. it is hypothesized to result from abnormal patellar tracking caused by altered motorcontrol. deficit in neuromotor control of the core may be a remote contributing factor to thedevelopment of pfp. application of reliable emg measures would be helpful to handle thistheory. therefore, the purpose of this study was to determine the test-retest reliability of thecore and vasti emg onsets, while ascending/descending stairs.: patellofemoral pain (pfp) is a common affliction and complex clinicalmethodsand core emg onsets during stair stepping were assessed two times a day. intraclass correlationcoefficients (iccs) and standard errors of measurement (sems) were calculated.: ten males with pfp and ten healthy controls participated in this study. vastiresultsonsets of control cases (icc 3,1 ≥ 0.70) except quadratus lumborum (ql) which showeda moderate reliability (icc for ascending=0.59 and for descending = 0.61). in controls,vasti in both tasks showed the highest absolute reliability. during ascending, highreliability (icc ≥ 0.70) in pfp group was demonstrated for all emg onsets except gluteusmaximus (gmax) and ql which showed a moderate reliability (icc = 0.69 and 0.63 respectively).in this group while descending stairs, all emg onsets showed high relativereliability (icc ≥ 0.70). moderate to high absolute reliability was obtained for onset timeswhile ascending/descending stairs in pfp group.: during both ascending/descending, high reliability was found for all emgconclusionreliability.: most emg onsets during stair ascending/descending had moderate to high