RESUMEN
Purpose: Manual therapy is used as a conservative treatment for people with low back pain (LBP). The scale of the problem encourages the search for the most effective methods to assess of manual treatment. Therefore, the aim of the study was to investigate magnitude of changes in muscle endurance using the Biering-Sorensen test (BST) and to analyse balance in patients with LBP treated with ERS and FRS muscle energy techniques (MET). Methods: The study included fifteen men with LBP (mean age: 42 years) working as automotive assemblers. Endurance of the biceps femoris (BF), gluteus maximus (GM) and erector spinae (ES) muscles were analysed using sEMG during the BST. The level of experienced pain, degree of disability and postural stability were also examined. Results before and after a three-week treatment cycle using MET were compared. Results: The MET therapy resulted in a reduction in pain ( p = 0.001), an improvement in the degree of disability ( p < 0.001) and an increase in the duration of the BST ( p < 0.001). After therapy, the values of the NMFs parameter indicating the degree of fatigue increased, i.e., ES muscle endurance increased, both right ( p = 0.004) and left ( p < 0.001). There was also a statistically significant decrease in the centre of pressure (COP) movement velocity in balance tests. Conclusions: The use of MET in patients with LBP increases muscle endurance, improves postural balance, and reduces pain levels on the VAS and disability levels according to the ODI. MET appears to be a good tool for preventing LBP.