부산대학교 도서관

Electromyographic (EMU) contralateral imbalances of back muscles are often interpreted as an aberrant back muscle pattern related to back pain. This study assessed different measurement properties (influence of the control of asymmetric efforts and of the force level, reliability, and sensitivity to low back status) of EMU imbalance parameters. Healthy controls (ii = 34) and chronic low back pain subjects (n = 55) stood in a dynamometer measuring the principal (extension) and coupled (lateral bending, axial rotation) L5IS 1 moments during isometric trunk extension efforts. The results showed that back pain subjects did not produce higher coupled moments than controls. Providing feedback of the axial rotation moment to correct asymmetric efforts during the task did not reduce EMU contralateral imbalances, except for some extreme cases. Normalized EMU imbalance parameters remain relatively constant between 40% and 80% of the maximal voluntary contraction. The reliability of EMU imbalance parameters was moderate, at best. Finally, neither low back status nor pain location had an effect on EMU contralateral imbalances. We conclude that the clinical relevance of EMU contralateral imbalances of back muscles remains to be established. [ABSTRACT FROM AUTHOR]