Effect Of Muscle Energy Technique On The Flexion-relaxation Phenomenon In Non-specific Lower Back Pain

Non-specific lower back pain(NLBP)is one of the most common causes of disability worldwide. In patients with NLBP, reduced lumbar flexion-relaxation and reduced variability of muscle activity distribution are reported as abnormal muscle activity. Muscle energy technique (MET) is used to be a conservative, non-pharmacological treatment method for somatic dysfunctions of the musculoskeletal system. However, the effect of MET approach on the flexion-relaxation phenomena (FRP) is unclear. PURPOSE: To investigate the effects of MET on pain, lumbar function, and FRP in patients with NLBP. METHODS: Thirty patients with NLBP were randomized into the MET group (5 females and 10 males: 21.9 ± 2.0 years, 1.72 ± 0.09 m, 67.3 ± 14.0 kg) and control group (7 females and 8 males: 20.9 ± 1.2 years, 1.73 ± 0.09 m, 65.0 ± 9.6 kg). They received MET intervention and health lecture series for 4 weeks, respectively. Pain score, lumbar dysfunction index (ODI), and FRR of the erector spinae (FRR-ES) and multifidus (FRR-M) during trunk flexion-relaxation test were measured before and after the intervention. Two-way analysis of variance with repeated measures was used to evaluate MET effects. RESULTS: Significant interactions were detected in pain score (P = 0.001, η2 = 0.308) and ODI score (P = 0.005, η2 = 0.244). Post-hoc comparisons showed that the pain score (from 5.07 ± 1.39 to 2.20 ± 1.32, P < 0.001) and ODI score (from 18.53 ± 5.83 to 10.00 ± 8.45, P < 0.001) were decreased at week 5 compared to week 0, respectively. Additionally, the pain score (P < 0.001) and ODI score (P < 0.001) were lower in the MET group compared to the control group at week 5, respectively. Similarly, significant interactions were detected in FRR-ES (P = 0.009, η2 = 0.244) and FRR-M (P = 0.047, η2 = 0.148). Post-hoc comparisons showed that the FRR-M (from 11.72 ± 5.73 to 14.79 ± 6.52, P = 0.028) was increased in the MET group, while the FRR-ES (from 17.30 ± 4.19 to 14.92 ± 4.47, P = 0.009) was decreased in the control group at week 5 compared to week 0, respectively. Additionally, no significant differences were detected for both FRR-ES (P = 0.328) and FRR-M (P = 0.864) between the MET group and the control group at week 5. CONCLUSIONS: MET could be recommended as one of the clinical treatments for NLBP to relieve pain and improve lumbar function. However, the effect of MET on the FRP is not yet evident.