Paul A. Bruno and Jeff Bagust
The objective of this study was to investigate whether any differences exist between subjects with and without low back pain (LBP) in the motor patterns of the gluteus maximus (GM), hamstring (HAM), contralateral erector spinae (CES), and ipsilateral erector spinae (IES) muscles during prone hip extension (PHE). A convenience sample of 31 non-LBP subjects and 20 unilateral LBP subjects performed two sets of five repetitions of PHE. Surface electromyography recorded the activity within the four muscles and a pressure transducer was used to determine the onset of leg movement. For the non-LBP sample, only the right leg was tested. In general, the LBP sample demonstrated greater within-set and between-set consistencies in both legs compared to the non-LBP sample. No distinct differences were found between the samples in terms of the frequency with which the individual activation orders were used or the frequency with which each muscle became active at a particular rank. Although several statistically significant differences were noted in the relative onset times of the muscles, the one consistent pattern to emerge from the data is that the activation of the GM was delayed in both legs of the LBP sample.
Clinical Chiropractic, Volume 10, Issue 2,