Use of the surface EMG coactivational pattern for functional evaluation oftrunk muscles in subjects with and without low-back pain

This study not only examined the differences among coactivational activitie s of eight trunk muscles in static holding tasks between normal subjects an d low-back pain (LBP) patients, but also selected an evaluation task for LB P patients from the experiment. In a study of 87 subjects, 47 with and 40 w ithout LBP, eight channels of EMG were recorded using a multichannel EMG sy stem. Surface IEMG signals of four right- and left-trunk muscles (rectus ab dominis, external oblique, erector spinae, and latissimus dorsi) were obtai ned in static holding tasks. Trunk muscle groups have different muscle coac tivational patterns in functional posture of load holding. For erector spin ae muscles, more significant IEMG pattern changes occurred than other trunk muscles between LBP patients and normal subjects in static holding tasks. Using surface IEMG of erector spinae muscle in static holding task can disc riminate LBP patients from normal subjects.