The effects of the lumbopelvic manipulation on the fatigability of the back and hip muscles in adults with chronic low back pain
Patients with chronic low back pain (CLBP) have been shown to have increased fatigability levels of hip and low back muscles as measured by the surface electromyographic (EMG) median frequency (MF). In addition, literature suggests that lumbopelvic manipulation could be an effective intervention for reducing CLBP. However, the effects of lumbopelvic manipulation on lumbar or hip muscle fatigability have not been studied previously. The purposes of the study were to examine the immediate and short-term effects of a single lumbopelvic manipulation on the muscle fatigability level of the lumbar multifidus (MULT), gluteus maximus (GMAX) and gluteus medius (GMED) muscles in addition to the pain level as compared to a placebo intervention in patients with CLBP. Thirty-one participants with CLBP, 30.2 ±10.1 years of age, completed the immediate effect part of the study, and 27 participants, 29.9 ±8.1years of age, completed the short-term effect part of the study. Three EMG electrodes were placed on the painful side of the MULT, GMAX and GMED muscles. For the immediate effect part of the study, EMG was collected during the modified Biering-Sorensen test five times: before the intervention, and immediately, 15 min, 30 min, and 45 min after the intervention. After the baseline EMG recording, each participant was randomized into one of two intervention groups: manipulation and placebo. Participants in the manipulation group received a high-velocity low amplitude lumbopelvic manipulation. Participants in the placebo group were set up in a position for the lumbopelvic manipulation, but did not receive a thrust. For the short-term effects part of the study, EMG of the three muscles were recorded during the modified Biering- Sorensen test three days and one week after the intervention. In addition, pain level was collected at all seven time points. There was no significant difference in the fatigability level of the three muscles between groups before and at 4 time points after the intervention. However, the manipulation group had a significant reduction in pain as compared to the placebo group between 15 and 30 min after the intervention (p = 0.032). In addition, there was no significant difference between groups on fatigability level of the three muscles three days and one week after intervention. Both groups had significant pain reduction three days (p = 0.019) and one week (p < 0.001) after the intervention. Although manual intervention had a positive effect on pain reduction, it did not alter the fatigability level of the back and hip muscles. Manual intervention can be a useful treatment approach to decrease pain in patients with CLBP. However, clinicians may consider other treatment options when the goal is to improve fatigability of the back and hip muscles for this patient population.