Kumamoto T1, Matsuda R2, Miura S3, Seko T1, Takahashi Y4
1Hokkaido Chitose College of Rehabilitation, Rehabilitation, Chitose, Japan, 2Shinnsapporo Neurosurgical Hospital, Rehabilitation, Sapporo, Japan, 3Hokusei Hospital, Rehabilitation, Chitose, Japan, 4Aizen Hospital, Rehabilitation, Sapporo, Japan
Background: Stiffness of the multifidus muscle is involved in lumbar backache in young and middle-aged adults, and trunk extension exercise in the standing position (TEESP) has been reported to improve and prevent lumbar backache. Relaxation of the multifidus muscle through this exercise potentially has led to alleviation of ischemic back pain. However, immediate effects of this exercise have not been studied in terms of the shear modulus.
Purpose: To build a lumbar muscle fatigue model for nonspecific pain and examine TEESP-induced musculophysiological changes of the multifidus muscle by shear wave elastography.
Methods: Thirty-three healthy volunteers (mean age: 23.7 years) were included in this study. Exclusion criteria included history of musculoskeletal disorder and central nervous system disease. As a lumbar muscle fatigue model, they underwent a 60-second Sorensen fatigue test (SFT). Thereafter, they were divided into the following three groups: F-Ex group performing TEESP as an exercise task; F-nEx group holding the standing position as an exercise task for the same period of time as in the F-Ex group after SFT; and nF-Ex group performing TEESP as an exercise task without undergoing prior SFT (11 individuals per group). With the palms of the hands placed on the posterior surfaces of the iliac crests when in a standing position, the starting standing position (pre-Ex) was defined as the 10 s after a 30-s acclimatization period. After the pre-Ex group, the participants in the F-Ex and nF-Ex groups were instructed to perform a trunk extension exercise for 4 s by extending their trunk as much as possible, maintaining the position for 10 s, returning to the standing position for over 4 s, and maintaining the standing position for 10 s (post-Ex). The shear modulus of multifidus muscle in the standing position was measured using an ultrasound imaging device with shear wave elastography (Aixplorer, SuperSonic Image, Aix-en-Provence, France) and a linear transducer (SL10-2) in the musculoskeletal mode. The transducer was placed 2cm lateral to the site of the spinous process of the 5th lumbar vertebra. A liner array probe was set parallel to the multifidus muscle fibers. Pre- and post-exercise data after SFT were quantitatively analyzed with an analysis software program. Reproducibility and intra-group and inter-group comparisons of shear modulus data were statistically tested at a significance level of 5%.
Results: No adverse events occurred in any subjects. The shear modulus reproducibility was ICC 0.90. In the intra-group comparisons, a significant decrease was found for the post-Ex value of the F-Ex group (p = 0.0146). In the inter-group comparisons, pre-Ex values of the F-Ex and F-nEx groups were significantly higher than the pre-Ex value of the nF-Ex group (p=0.0005, 0.0005), and post-Ex values of the F-Ex and nF-Ex groups were significantly lower than the post-Ex value of the F-nEx group (p=0.0022, 0.000).
Conclusion(s): Trunk extension exercise for muscle fatigue showed decreases in the elastic modulus of multifidus muscle.
Implications: Trunk extension exercise is expected to alleviate fatigue lumbar backache through muscle relaxation.
Keywords: Low back pain, Trunk extension exercise, Shear wave elastography
Funding acknowledgements: The study was supported by a grant from the JSPS KAKENHI Grant Number JP17K01517.
Purpose: To build a lumbar muscle fatigue model for nonspecific pain and examine TEESP-induced musculophysiological changes of the multifidus muscle by shear wave elastography.
Methods: Thirty-three healthy volunteers (mean age: 23.7 years) were included in this study. Exclusion criteria included history of musculoskeletal disorder and central nervous system disease. As a lumbar muscle fatigue model, they underwent a 60-second Sorensen fatigue test (SFT). Thereafter, they were divided into the following three groups: F-Ex group performing TEESP as an exercise task; F-nEx group holding the standing position as an exercise task for the same period of time as in the F-Ex group after SFT; and nF-Ex group performing TEESP as an exercise task without undergoing prior SFT (11 individuals per group). With the palms of the hands placed on the posterior surfaces of the iliac crests when in a standing position, the starting standing position (pre-Ex) was defined as the 10 s after a 30-s acclimatization period. After the pre-Ex group, the participants in the F-Ex and nF-Ex groups were instructed to perform a trunk extension exercise for 4 s by extending their trunk as much as possible, maintaining the position for 10 s, returning to the standing position for over 4 s, and maintaining the standing position for 10 s (post-Ex). The shear modulus of multifidus muscle in the standing position was measured using an ultrasound imaging device with shear wave elastography (Aixplorer, SuperSonic Image, Aix-en-Provence, France) and a linear transducer (SL10-2) in the musculoskeletal mode. The transducer was placed 2cm lateral to the site of the spinous process of the 5th lumbar vertebra. A liner array probe was set parallel to the multifidus muscle fibers. Pre- and post-exercise data after SFT were quantitatively analyzed with an analysis software program. Reproducibility and intra-group and inter-group comparisons of shear modulus data were statistically tested at a significance level of 5%.
Results: No adverse events occurred in any subjects. The shear modulus reproducibility was ICC 0.90. In the intra-group comparisons, a significant decrease was found for the post-Ex value of the F-Ex group (p = 0.0146). In the inter-group comparisons, pre-Ex values of the F-Ex and F-nEx groups were significantly higher than the pre-Ex value of the nF-Ex group (p=0.0005, 0.0005), and post-Ex values of the F-Ex and nF-Ex groups were significantly lower than the post-Ex value of the F-nEx group (p=0.0022, 0.000).
Conclusion(s): Trunk extension exercise for muscle fatigue showed decreases in the elastic modulus of multifidus muscle.
Implications: Trunk extension exercise is expected to alleviate fatigue lumbar backache through muscle relaxation.
Keywords: Low back pain, Trunk extension exercise, Shear wave elastography
Funding acknowledgements: The study was supported by a grant from the JSPS KAKENHI Grant Number JP17K01517.
Topic: Musculoskeletal: spine; Musculoskeletal; Orthopaedics
Ethics approval required: Yes
Institution: Hokkaido Chitose College of Rehabilitation
Ethics committee: Research Ethics Committee Hokkaido Chitose College of Rehabilitation
Ethics number: 18001
All authors, affiliations and abstracts have been published as submitted.
