S99. Reliability of surface electromiography measures for latissimus dorsi, femoral biceps and paraspinal muscles in persons with low back pain

Abstract

Eighty percent of the population have experienced at least one episode of low back pain (LBP) in their lifetime and approximately 13–19% of adults complain of suffering LBP associated to lifting loads. Latissimus dorsi (LD), femoral biceps (FB) and the paraspinal muscles (PS), have an important role in the stability of the lumbosacral spine. It has been observed that during daily life activities the muscles show different electromyographic responses, depending on factors such as the health condition in which they are studied and the posture in which the measurement is made, among others.The surface electromyography (sEMG) is a non-invasive method that assesses muscle activation and provides relevant information that helps to understand the motor control in people with idiopathic chronic LBP; however, there are no reports in literature about the sEMG reliability during lifting a load for the above-mentioned muscles in people with chronic LBP. Objective: to determine the inter-session reliability of the sEMG for LD, FB and PS muscles, during lifting a load in people with chronic LBP. There were included 10 people (7 women and 3 men) with chronic LBP, between 18 and 40 years (32 ± 4.1) and body mass index 27.4 ± 6.04. The sEMG activity of the LD, FB and PS muscles was assessed while lifting a load in a symmetrical bipedal position in two sessions, with five days between each assessment. The Root mean square (RMS) amplitude and the latency were calculated. The inter-session reliability was assessed through Intraclass Correlation Coefficient (ICC) 2,1 and Bland–Altman analysis. Surface EMG measurements presented moderate to good reliability in latency measures for all assessed muscles (ICC 0.49–0.77 for LD, 0.46–0.56 for FB and 0.59–074 for PS muscles) and displayed moderate to excellent reliability for the RMS amplitude (ICC values 0.46–0.8 for LD; 0.42–0.55 for FB and 0.43–0.68 for PS muscles). Bland–Altman analysis showed a mean value of the difference close to zero and limits of agreement between 2 and 4 ms. The sEMG is a reliable tool that can be useful to evaluate muscle activation during a functional activity, in order to help to understand the muscle activation patterns in people with idiopathic chronic LBP.