ABSTRACT: The evidence on the role of leg-length discrepancy (LLD) in low back pain (LBP) is contradictory, possibly due to the diversity of measurement methods.
To assess the reliability of a laser-based ultrasound method and its agreement with the radiographic method.
The measurement device consisted of a laser measure fixed to a rod holding the scanning head of the ultrasound and could be moved automatically by a linear actuator. The reliability of the measurement was evaluated using 20 healthy voluntary subjects with no known previous LLD (90% women, mean age 23 years). We assessed the agreement of the ultrasound method with a radiographic LLD measurement using 19 voluntary patients (95% men, mean age 38 years), who had had radiographic LLD measurements taken during the previous year. We used intraclass correlation co-efficients (ICC) and Bland & Altman analysis in the statistical analysis.
The ICC value for agreement between methods was 0.97 (95% confidence intervals [CI] 0.93-0.99) indicating almost perfect agreement. The ICC values for both raters indicated almost perfect agreement between repeated measurements (ICC 0.996 and 0.994, respectively). In the Bland and Altman analysis, the mean difference was close to zero (0.56 mm and 0.40 mm), indicating minimal systematic error.
The ultrasound-laser technique is quick and easy to perform. Both reliability and agreement with the radiographic method are excellent. The ultrasound measurement is non-invasive and therefore a potential alternative to radiographic methods in the evaluation of LLD.
Acta Radiologica 11/2011; 52(10):1143-6. · 1.37 Impact Factor
ABSTRACT: A cross-sectional imaging study of young adults.
To evaluate whether severity of low back symptoms predicts atrophy in the paraspinal muscles of young adults.
Although an increased fat content of the lumbar muscles has been observed among adults with chronic LBP, there is limited knowledge of this association in younger populations.
The population-based study sample consisted of 554 subjects (321 females and 233 males) from the 1986 Northern Finland Birth Cohort. Latent Class Analysis (LCA) was used to cluster the subjects according to the low back symptoms and functional limitations at 18, 19, and 21 years. The mean age of the subjects at the time of the MRI (magnetic resonance imaging) was 21 years (range, 20-23). Muscle atrophy was evaluated by assessing the fat content of the paraspinal muscles using Opposed-Phase MRI. The cross-sectional areas (CSAs) of the erector spinae and multifidus muscles were also measured.
LCA analysis produced five clusters differing in symptoms, ranging from a cluster (n = 65) in which subjects had high likelihood of symptoms and functional limitations at all time points, to a cluster (n = 165) with no pain ever. The fat content of the multifidus muscles was significantly higher among women than men (14.0% vs. 5.3%, P < 0.001), but it was not significantly associated with symptom severity. The CSA of both erector spinae and multifidus muscles were significantly larger among men than women (P < 0.001 in all of the muscles), but were not associated with pain severity.
Low back symptoms and functional limitations over a 3-year period were not associated with increased fat content or a reduction in the cross-sectional area of lumbar paraspinal muscles among young adults.
Spine 02/2011; 36(23):1961-8. · 2.08 Impact Factor
ABSTRACT: To study how time spent in physical activity and that in television (TV) viewing are associated with muscular fitness among young adults.
The study population consisted of a cross-sectional sample of 381 males and 493 females aged 19.1 yr (SD 0.3) from the Northern Finland Birth Cohort 1986. Muscular fitness was measured by trunk muscle strength tests (trunk extension, flexion, and rotation) and jumping height test. Time spent on moderate- to vigorous-intensity physical activity and on TV viewing was self-reported by a questionnaire.
The most physically active young adults performed significantly better in most trunk muscle strength tests and the jumping test than the least active subjects. The mean difference between the most and least active groups was at minimum 1.6 kg (95% confidence interval (CI) = -0.5 to 3.7) and at maximum 10.6 kg (95% CI = 4.7-16.5) for different trunk muscle strength tests and at minimum 4.4 cm (95% CI = 2.7-6.1) for the jumping height test. Males and females who watched TV for >or=2 h x d(-1) performed significantly worse in trunk extension and flexion tests and females also performed worse in the jumping test compared with those who watched TV <2 h x d(-1), independent of their physical activity level. The mean difference between low and high TV users was at minimum -3.8 kg (95% CI = -6.7 to -0.9) for trunk extension and flexion strength and -1.2 cm (95% CI = -2.0 to -0.4) for jumping height in females.
Among young adults, daily TV viewing for >or=2 h, irrespective of physical activity level, was associated with poorer muscular fitness.
Medicine and science in sports and exercise 10/2009; 41(11):1997-2002. · 3.71 Impact Factor
ABSTRACT: A cross-sectional study on young adults.
To evaluate the relationships between low back pain (LBP), maximal isometric trunk muscle strength, and body sway among young adults.
The results of previous studies evaluating the association between trunk muscle strength and LBP are conflicting and heterogeneous. Furthermore, there are only few studies on the association between body sway and LBP.
The subjects (n = 874) belonged to a subcohort of the Northern Finland Birth Cohort 1986 (mean age 19 years). Trunk muscle strength and body sway were measured from all subjects. LBP symptoms were inquired with a questionnaire, which was completed concurrently with the examinations. Latent Class Analysis (LCA) was used to cluster the subjects according to their LBP symptoms.
LCA analysis produced 6 clusters differing with respect to LBP symptoms. There were no statistically significant differences between the clusters in trunk muscle strength or body sway.
LBP does not seem to be associated with maximal isometric trunk muscle strength or body sway in young adults.
Spine 06/2008; 33(13):E435-41. · 2.08 Impact Factor