The responses of trunk muscles to perturbations before and after Active Release Technique® of the hip flexor

Abstract

<p>The purpose of this study was to investigate the influence of a passive myofascial therapy treatment (Active Release Technique^® (A.R.T^®)) on various outcome measures with an asymptomatic tight hip flexor group (A-THF) (n=8) and a low back pain tight hip flexor group (LBP-THF) (n=10). These two groups were also compared with a control group (CON) (n=8) The outcome measures for this study were: 1) Tnmk muscle EMG measurements monitoring unloading perturbations (Unknown Timing (UT) and Known Timing (KT)) and Unstable Standing (US) perturbations. 2) Maximum voluntary trunk flexor and extensor moments (Flex_Max and Ext_Max), 3) disability and pain measurements (RMDQ and VAS) with self-efficacy (PSEQ) evaluated as a covariate. 4) Hip extension mobility.</p> <p>The results from this study demonstrated both significant short term and sustained improvements in trunk Flex_Max and Ext_Max. For the THF groups, A.R.T® resulted in significant acute (within session) increases in Ext_Max of 20.6%, 11.9% and 12.3% on days 1,3 and 4, respectively. After the 2 week treatment program was completed, the THF Groups demonstrated an average increase in Ext_Max of 25% compared with their baseline values. After the treatment, the LBP-THF group had trunk Flex_Max and Ext_Max values that were 34% and 32.3%, respectively, compared with the CON group.</p> <p>The full treatment program of the LBP-THF group was associated with a reduction in disability by 2.8 points and pain by 2.9 cm. Interestingly, self-efficacy was found to be a significant covariate for the disability outcome measure. For the passive hip extension measurements, the LBP-THF group and the A-THF groups increased their values by 13.10 and 8.0°, respectively. In addition, the other two hip extension tests (knee extended and knee bent tests) demonstrated significant increases in measured passive hip extension values over the course of the A.R.T^® treatment and, by the end of the study, the LBP-THF groups' hip extension values were not significantly different from that of the CON group.</p> <p>The US perturbation trials showed a significant decrease in average muscle activity for the TES, LES, MULT and GLUT muscles over the course of the treatment program, but there were no significant and clinically relevant changes observed in anticipatory adjustment and baseline muscle activity for the KT and UT perturbation trials. However, after the treatment program, there was a trend for the THF Groups' baseline and anticipatory adjustment EMG ampltidues to shift closer to those of the CON group for most muscles.</p> <p>The results from this study suggest that the utilization of A.R.T^® can result in clinically important benefits, for patients with tight hip flexors and low back pain ,by decreasing pain and disability while improving trunk strength and hip extension flexibility.</p>