Magnitude of spinal muscle damage is not statistically associated with exercise-induced low back pain intensity.

Bishop, Mark D

Horn, Maggie E

Lott, Donovan J

Arpan, Ishu

George, Steven Z

United States

2016-09-14T14:24:40Z

2011-12

BACKGROUND CONTEXT: Findings on imaging of noncontractile anatomic abnormalities and the intensity of low back pain have weak associations because of false-positive rates among asymptomatic individuals. This association might be stronger for contractile tissues. PURPOSE: The purpose of this study was to examine the relationship between location and reports of pain intensity in the low back and exercise-induced muscle damage to the lumbar paraspinal muscles. STUDY DESIGN: Nondiagnostic observational study in a laboratory setting. METHODS: Delayed onset muscle soreness was induced in the low back of healthy pain-free volunteers. Measures of pain intensity (100-mm visual analog scale [VAS]) and location (area on the pain diagram) were taken before and 48 hours after exercise. Muscle damage was quantified using mechanical pain thresholds, motor performance deficits, and transverse relaxation time (T2)-weighted magnetic resonance imaging (MRI). Changes pre- to postexercise in signal intensity on T2-weighted imaging within the erector spinae, pain intensity, pain area, mechanical pain threshold, and isometric torque were assessed using paired t tests. Bivariate correlations were conducted to assess associations among muscle damage, pain intensity, and pain drawing area. RESULTS: Twenty participants volunteered (11 women; average age, 22.3 years; average body mass index, 23.5) for study participation. Reports of pain intensity at 48 hours ranged from 0 to 59 mm on the VAS. Muscle damage was confirmed by reductions in mechanical threshold (p=.011) and motor performance (p<.001) and by changes in T2-weighted MRI (p=.007). This study was powered to find an association of at least r=0.5 to be statistically significant. Correlations of continuous variables revealed no significant correlations between pain intensity and measures of muscle damage (ranging between -0.075 and 0.151). There was a significant association between the remaining torque deficit at 48 hours and pain area. CONCLUSIONS: The results of this study indicate that there was no association between the magnitude of muscle damage in the lumbar erector spinae and reported pain intensity in the low back. In future studies, larger cohorts may report statistically significant associations, but our data suggest that there will be low magnitude potentially indicating limited clinical relevance.

http://www.ncbi.nlm.nih.gov/pubmed/22208857

S1529-9430(11)01397-0

1878-1632

https://hdl.handle.net/10161/12765

eng

Elsevier BV

Spine J

10.1016/j.spinee.2011.11.005

Exercise

Exercise Test

Exercise Tolerance

Female

Humans

Low Back Pain

Magnetic Resonance Imaging

Male

Muscle Contraction

Muscle Fatigue

Muscle, Skeletal

Musculoskeletal Pain

Pain Measurement

Spine

Young Adult

Magnitude of spinal muscle damage is not statistically associated with exercise-induced low back pain intensity.

Journal article

Horn, Maggie E|0000-0002-3963-7389

George, Steven Z|0000-0003-4988-9421

http://www.ncbi.nlm.nih.gov/pubmed/22208857

1135

1142

12

Clinical Science Departments

Duke

Duke Clinical Research Institute

Institutes and Centers

Orthopaedics

Orthopaedics, Physical Therapy

School of Medicine

Published

11