Efforts to express objectively subjective data on chronic low back pain stimulated the implementation of a number of studies which attempt to detect „typical” significant changes in the recruiting of activity, mostly of paravertebral erectors. From a number of publications ensues that there are differences in the activity of these muscles in healthy subjects and in patients with so-called non-specific chronic low back pain. Findings assembled hitherto are frequently controversial, the investigations use different methods, a different way of activation of participating muscles. Result: so far there is no statistically trustworthy investigation confirming significantly abnormal changes of activation of paravertebral erectors in patients suffering from chronic low back pain, as compared with a population sample without this painful experience.

        Key words: low back pain, EMG