Electromyographic patterns of trunk muscles in asymmetrical trunk postures and while load-carrying with spinal rotation
10.3760/cma.j.issn.0254-1424.2014.03.011
- VernacularTitle:脊柱旋转下不同非均匀姿势和持重时躯干肌的表面肌电活动规律
- Author:
Qiangmin HUANG
;
Shuai FAN
;
Fenghu WANG
- Publication Type:Journal Article
- Keywords:
Trunk posture;
Surface electromyography;
Biomechanics;
Load carrying;
Spine rotation
- From:
Chinese Journal of Physical Medicine and Rehabilitation
2014;36(3):204-209
- CountryChina
- Language:Chinese
-
Abstract:
Objective To observe the activation patterns in surface electromyographs (sEMGs) of the lumbar dorsal and ventral muscles and the gluteus medius during asymmetrical trunk postures and while carrying loads with the trunk rotated.Methods sEMGs were recorded from ten healthy men as they stood with their feet in 5 positions-rotated clockwise 0°,45°,90°,135° and 180° with respect to the initial plane of the torso.With each foot position they stood in 3 postures:upright,in lateral flexion and in lateral extension.Each posture was recorded with and without carrying a load of 20 kg by the right hand.The EMG activities of the rectus abdominis (RA),obliquus externus abdominis (EO),erector spinae (ES),multifidus (LM) and gluteus medius (GM) on both sides were recorded.Trunk displacement was monitored by 8 cameras.The EMG data of each muscle were normalized with readings from a maximal voluntary contraction (MVC) of the muscle.Results With the feet at 0° and no load the muscle activities on both sides were 1％-2％ of the MVC readings.With a 20 kg load the percentage was 3％-13％.With the feet at 45° and no load the activities were greater,except in the RA on the contralateral side.With no load at 90°,135° and 180° the muscle activities were greater,but a few muscles in the two extreme trunk postures showed greater activity only on one side,especially the ES and LM.With a load and rotational torque in the spine,the ventral muscles were less active but the dorsal muscles were significantly more active on both sides.Conclusion Standing with rotation of the spine,the activity of some trunk muscles shows great asymmetry,particularly with asymmetric loading of the arms.This might create a phenomenon of lumbar flashing and it could possibly be one of the pathological bases of acute lumbar sprain.
