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Y. Oka1, T. Jiroumaru2, M. Ikeya2, M. Wachi2, S. Noguchi2,3, Y. Hyodo1,3, N. Kanazawa2
1Kanazawa Orthopedic ＆ Sports Medicine Clinic, Ritto, Japan, 2Biwako Professional University of Rehabilitation, Physical Therapy, Higashiomi, Japan, 3Kyoto lnstitute of Technology, Kyoto, Japan
Background: In recent years, several studies have reported on the muscle activities during motion performance in people with low back pain (LBP). In healthy participants, the muscle activity of the iliocostalis decreased at the end of trunk extension in the standing position. Floyed (1951) named this phenomenon the flexion relaxation phenomenon (FRP). Disappearance of FRP is related to exacerbation of LBP, and can be an objective index for the effect of intervention (Geisser et al. 2005).
However, no study has investigated the trunk muscle activity pattern during trunk extension. Furthermore, no study has measured the muscle activity patterns of both the trunk and hip joints using chronic low back pain (CLBP) participants with disappeared FRP.
However, no study has investigated the trunk muscle activity pattern during trunk extension. Furthermore, no study has measured the muscle activity patterns of both the trunk and hip joints using chronic low back pain (CLBP) participants with disappeared FRP.
Purpose: The purpose of this study was to measure the muscle activity patterns of the trunk and hip joint muscles using electromyography (EMG) in the standing position at both neutral and end-range of trunk extension. Patterns were subsequently compared between the healthy and CLBP groups.
Methods: Altogether, 22 participants were recruited (mean age 21.9±2.8), including 12 healthy volunteers and 10 LBP patients. The participants who had no history of neuropathic or orthopaedic disease within six months and who presented FRP of the iliocostalis lumborum were eligible for the healthy group. The LBP group had continuous pain for more than three months in the lumbosacral region, without neural symptoms on the lower limbs, and disappeared FRP.
Results: During neutral standing posture and end-range of trunk extension, the muscle activities were measured using EMG. The following muscles on the right side were assessed: iliocostalis lumborum, iliocostalis thoracis, lumbar multifidus, rectus abdominal, external abdominal, internal abdominal, upper, and lower portions of the glutaeus maximus, iliopsoas, tensor fascia latae, rectus femoris, and Sartorius. The acquired EMG data were rectified with root mean square (RMS) and normalised based on the maximum voluntary contraction by manual muscle testing. The RMS of each muscle in the neutral standing position and end-range of trunk extension were analysed using a paired t-test (p<0.05).
The activity of each muscle was compared in a neutral standing position and end-range trunk extension in both groups. The activity of the Iliocostalis lumborum, iliocostalis thoracis, and upper portion of the glutaeus maximus showed a significant decrease in the end-range of trunk extension in the healthy volunteer group (p<0.05). In contrast, the LBP group did not show a significant decrease in the activity of these muscles in the end-range of trunk extension (p>0.05).
The activity of each muscle was compared in a neutral standing position and end-range trunk extension in both groups. The activity of the Iliocostalis lumborum, iliocostalis thoracis, and upper portion of the glutaeus maximus showed a significant decrease in the end-range of trunk extension in the healthy volunteer group (p<0.05). In contrast, the LBP group did not show a significant decrease in the activity of these muscles in the end-range of trunk extension (p>0.05).
Conclusion(s): In the end-range of trunk extension, healthy participants had a significant decrease in the activity of the iliocostalis lumborum, iliocostalis thoracis, and the upper portion of the glutaeus maximus, while LBP participants with non-appearance of FRP did not show a significant decrease in these muscle activities.
These findings showed that participants with CLBP with disappeared FRP had difficulties in muscle relaxation in both flexion and extension of the trunk.
These findings showed that participants with CLBP with disappeared FRP had difficulties in muscle relaxation in both flexion and extension of the trunk.
Implications: This study can contribute to improving physiotherapy evaluation and intervention for people with CLBP who do not have FRP.
Funding, acknowledgements: Nothing
Keywords: Chronic low back pain, Trunk extension, Muscle activity patterns
Topic: Musculoskeletal
Did this work require ethics approval? Yes
Institution: Aino university
Committee: Ethics Committee of Aino University
Ethics number: Aino-2013-02
All authors, affiliations and abstracts have been published as submitted.
