Electromyographic evaluation of selected muscles during active hip extension in men treated McKenzie method

Purpose: The aim of this study was to evaluate objective results of short-term treatment with the use of electromyography and to determine changes in muscle recruitment during the prone hip extension test in individuals with chronic low back pain who underwent the McKenzie treatment. Methods: The studied group consisted of 17 male office workers aged 33-55 who underwent two experimental sessions comprising of 3 measurements and the McKenzie method of mechanical diagnosis and therapy. Electromyographic examination of selected muscles was performed during the test in order to assess changes in their activity before and after the McKenzie method and the Visual Analogue Scale was used to assess the level of pain. Results: There was a tendency towards significance at the beginning of activation between the first and second test for the left erector spinae muscle (p = 0.0684). In 18% of patients, the onset activation time decreased, which is indicative of correct direction of changes. No statistically significant changes were observed in the remaining muscles. Statistical significance (p = 0.0131) was observed between the first and third test for the left erector spinae muscle. A decrease in the onset activation time was observed in 75% of the subjects. Effectiveness increased by as much as 57%. The level of pain decreased in the third test compared to the first one (p = 0.0240). However, the change in pain sensations between the first and second test was not statistically significant. Conclusions: The study showed objective changes in the activation sequence of selected muscles and subjective changes in pain following short term McKenzie therapy.