A cross-sectional, case-control study.
To investigate associations between physical fitness measures and disabilities related to back pain and quality of life (QOL) by the presence of symptomatic lumbar spinal stenosis (LSS) in elderly Korean women.
LSS leads to decreased functioning and reduced QOL. However, correlations among physical fitness, disability, and QOL have not been investigated in elderly women with LSS.
Participants included women aged 65 years and older (n=192), divided into a study group (n=38) and a control group (n=154) based on the presence/absence of LSS. All participants underwent physical function and fitness tests. Oswestry disability index (ODI) scores and EuroQol five-dimensional questionnaire (EQ-5D-5L) scores were used to assess disability and health-related QOL.
The results for the handgrip strength, sit-and-reach, functional reach, and timed up and go (TUG) tests were significantly higher in the control group than the LSS group. ODI scores were significantly higher and EQ-5D-5L scores significantly lower in the LSS group. TUG and functional reach test scores were significantly correlated with ODI scores, and handgrip strength was strongly interrelated with ODI and EQ-5D-5L scores in the LSS group. No other physical fitness measures showed statistically significant relationships with ODI or EQ-5D-5L scores.
In elderly Korean women with LSS, back pain-related disability and QOL are significantly associated with some physical fitness parameters such as handgrip strength. Handgrip strength reflects general muscle strength, which is significantly interrelated with the level of disability and QOL. Our results suggest that enhancing generalized muscle strength helps to reduce disability due to back pain and improve QOL in patients with LSS.
Lumbar spinal stenosis (LSS) is a degenerative spinal disease that results in progressive narrowing of the spinal canal, leading to compression of the nerve root [
Physical fitness represents a person's general physical health status [
As LSS is a major cause of physical inactivity and functional impairment, patients with LSS often experience a decline in physical fitness. Decreased physical fitness can be a common factor leading to pain in older adults. Moreover, decreased physical fitness contributes to decline in QOL and the activities of daily living. Therefore, a strong interrelationship may exist between physical fitness and LSS. However, few studies have investigated these associations. We investigated the association between the degree of disability from back pain, QOL, and physical fitness parameters in women with LSS aged over 65 years.
We designed this cross-sectional study as part of a national program to develop criterion-referenced health-related fitness standards for the National Fitness Award, conducted between March and November 2014. The study was approved by the Institutional Review Board of the corresponding author's organization (IRB no. B-1405/252-005). Written informed consent was obtained from all participants before enrollment in the study. The study included two groups: a study group (LSS group), consisting of symptomatic patients with LSS who visited the spine center at the last author's hospital, and a control group, comprising randomly chosen women from six cities in Korea. Inclusion criteria for the LSS group were (1) women aged between 65 and 85 years, (2) stenotic lesion in the lumbar spine confirmed via radiology, and (3) symptoms (one or more) of gluteal/lower extremity pain or numbness exacerbated by walking or standing, which was improved or resolved by sitting or bending forward, motor function deficits in the lower extremities and buttocks, and bladder/bowel dysfunction thought to be caused by spinal stenosis [
Measurements used to assess the relationships among different parameters were taken after confirmation of inclusion and exclusion criteria. All data were collected by blinded clinical research assistants. Anthropometric data were collected for comparison of basic characteristics between the two groups. Height and weight were measured using standard methods. Body mass index (BMI) was calculated as weight divided by the square of height (kg/m2). Body composition, including fat content (%) and skeletal muscle mass (kg), was measured with bioimpedance analysis using InBody 720 (Inbody Corp., Seoul, Korea), a tool approved by the US Food and Drug Administration and validated by research [
All testing sessions were conducted by experienced standardized researchers.
Muscular strength was assessed by a handgrip strength test [
Muscle endurance was assessed with a cross-arm sit-up test [
Participants' general flexibility was assessed with a sit-and-reach test [
For the prone trunk extension and chest raise test, participants were instructed to lie flat on the floor in a prone position with both hands under their thighs [
The back-muscle endurance of each participant was assessed with the prone isometric chest raise test [
For the STS, participants were asked to sit in the middle of a standard chair (43 cm) without arm rests and with a straight back and crossing both arms over the chest [
For the functional reach test, a yardstick was prepared and attached to a flat wall at approximately shoulder height. Participants were instructed to stand close to the wall and raise their arms with a closed fist and a shoulder flexion of 90° [
The TUG test was performed to assess participants' mobility and balance [
Data are expressed as mean±standard deviation. Clinical characteristics were compared between the control and LSS groups using Student's t tests. Analysis of covariance was used to determine the differences in physical fitness test results and ODI and QOL scores between the two groups after adjusting for age and BMI. Pearson's partial correlation analyses were performed to assess the relationships between the physical fitness measures and ODI and QOL scores between the control and LSS groups after adjusting for age and BMI. Analyses were performed with SPSS ver. 18.0 (SPSS Inc., Chicago, IL, USA) and the level of statistical significance was set as
After adjusting for age and BMI, handgrip strength (21.7±3.9 vs. 19.4±4.5,
In the control group, the prone trunk extension test (
Our cross-sectional study demonstrated that some physical fitness test results (handgrip strength, sit-and-reach, STS, functional reach, and TUG) were significantly lower in the LSS group than in the control group after adjusting for age and BMI. Furthermore, handgrip strength, functional reach, and TUG test results were significantly associated with back pain-related disability and QOL in the LSS group.
Our findings of the differences between the LSS and control groups in the physical fitness tests are consistent with those of a previous study. Kim et al. [
In our study, the results of handgrip strength, functional reach, and TUG tests in the LSS group were significantly related to ODI, but only handgrip strength was related to QOL. In LSS, back pain is known to lead to disturbance in standing and walking, which ultimately results in disability. As the functional reach test reflects stability and the TUG test reflects mobility and balance, it is possible that participants with more severe problems with walking and stability will complain of a higher degree of disability related to back pain. However, in contrast to other tests, handgrip strength is not directly dependent on the symptoms of spinal stenosis, but rather reflects generalized muscle strength. Therefore, our results suggest a possible association between generalized muscle weakness and the pathogenesis of LSS. Handgrip strength was the only factor that was correlated with both ODI and QOL in the LSS group. A comprehensive understanding of the mechanism that explains the relationships among handgrip strength, back pain, and QOL is yet to be reached. However, we suggest a possible hypothesis based on our findings. First, enhanced basal muscle tone may reduce peripheral sensitization and pain [
Our study has some limitations. First, the cross-sectional design could not determine any causality. Second, only a small number of women were assigned to the LSS group, making it is impossible to generalize our results. Third, we defined the LSS group based on simple radiography findings and subjective symptoms. Finally, we did not measure appendicular muscle mass, which reflects the muscle mass of the body, but only measured muscle strength.
In conclusion, elderly women with LSS showed significantly lower physical fitness than the control group. Some physical fitness test results were also associated with the degree of disability related to back pain and QOL in the LSS group. In particular, handgrip strength (which reflects generalized muscle strength and is not considered to be influenced by LSS symptoms) was significantly lower in the LSS group than in the control group, and was correlated with the degree of disability and QOL in the LSS group. Although we could not determine causality, our results collectively suggest that enhancing muscle strength reduces the degree of disability due to back pain and improves QOL in patients with LSS. Further prospective, large-scale studies are required to verify our findings.
This study was supported by the National Health Promotion Fund, 2014.
Values are presented as mean±standard deviation.
LSS, lumbar spinal stenosis.
a)Derived with Student's
Values are presented as mean±standard deviation.
QOL, quality of life; LSS, lumbar spinal stenosis; ODI, Oswestry disability index; EQ-5D-5L, EuroQol five-dimensional questionnaire.
a)Derived with Student's
QOL, quality of life; ODI, Oswestry disability index; EQ-5D-5L, EuroQol five-dimensional questionnaire.
a)Data are derived with partial correlation analysis between physical fitness tests and ODI, EQ-5D-5L after adjusting for age and body-mass index; b)Values are presented as