Low-dose, non-supervised, health insurance initiated exercise for the treatment and prevention of chronic low back pain in employees. Results from a randomized controlled trial

<div><p>Objective</p><p>Back pain is a major problem requiring pragmatic interventions, low in costs for health care providers and feasible for individuals to perform. Our objective was to test the effectiveness of a low-dose 5-month exercise intervention with small personnel investment on low back strength and self-perceived pain.</p><p>Methods</p><p>Two hundred twenty-six employees (age: 42.7±10.2 years) from three mid-size companies were randomized to 5-month non-supervised training at home (3 times/week for 20 minutes) or wait-list-control. Health insurance professionals instructed the participants on trunk exercises at the start and then supervised participants once a month.</p><p>Results</p><p>Muscle strength for back extension increased after the 5-month intervention with a significant between-group difference (mean 27.4 Newton [95%CI 2.2; 60.3]) favoring the exercise group (p = 0.035). Low back pain was reduced more in subjects after exercise than control (mean difference –0.74 cm [95%CI –1.17; –0.27], p = 0.002). No between-group differences were observed for back pain related disability and work ability. After stratified analysis only subjects with preexisting chronic low back pain showed a between-group difference (exercise versus controls) after the intervention in their strength for back extension (mean 55.7 Newton [95%CI 2.8; 108.5], p = 0.039), self-perceived pain (mean –1.42 cm [95%CI –2.32; –0.51], p = 0.003) and work ability (mean 2.1 points [95%CI 0.2; 4.0], p = 0.032). Significant between-group differences were not observed in subjects without low back pain: strength for back extension (mean 23.4 Newton [95%CI –11.2; 58.1], p = 0.184), self-perceived pain (mean –0.48 cm [95%CI –0.99; 0.04], p = 0.067) and work ability (mean –0.1 points [95%CI –0.9; 0.9], p = 0.999). An interaction between low back pain subgroups and the study intervention (exercise versus control) was exclusively observed for the work ability index (p = 0.016).</p><p>Conclusion</p><p>In middle-aged employees a low-dose, non-supervised exercise program implemented over 20 weeks improved trunk muscle strength and low back pain, and in those with preexisting chronic low back pain improved work ability.</p></div

Baseline data and differences between groups over time for subjects with and without chronic low.

<p>Baseline data and differences between groups over time for subjects with and without chronic low.</p

CONSORT flow diagram of the progress throughout the study.

<p>CONSORT flow diagram of the progress throughout the study.</p

Changes from baseline for each study group and mean differences between groups for primary and key secondary outcomes.

<p>Changes from baseline for each study group and mean differences between groups for primary and key secondary outcomes.</p

Effects of 5 months of exercise for subjects with or without pre-existing chronic low back pain.

<p>Maximum force for isometric low back extension (left panel), low back pain as assessed with a 10 cm visual analog scale (VAS, middle panel), and the work ability index (total score) from the work ability questionnaire (right panel) before and after 5 months exercise or control. Subjects are stratified for the presence of chronic low back pain at baseline, defined as having experienced low back pain almost every day for a minimum of three months per year. Data are mean ± SE. The framed p-values are given for between-group differences (exercise- versus control group) over time as analyzed with an ANCOVA model. * indicates p<0.05 for the interaction (subgroup [chronic LBP or no chronic LBP] x intervention [exercise or control]) included as covariate in the primary analysis model.</p

Low back pain and related disability before and after 5 months of exercise.

<p>Low back pain as assessed with a 10-cm visual analog scale (VAS, upper panel) and the low back pain disability score from the Oswestry Low Back Pain Disability Questionnaire for the exercise and control group at baseline and after 5 months intervention. Data are mean ± SE. * indicates p<0.01 for within-group differences (pre versus post-intervention) as analyzed with Students t-test for paired samples. The framed p-value represents between-group differences (exercise- versus control group) over time as analyzed with an ANCOVA model.</p

Subject characteristics at baseline.

<p>Subject characteristics at baseline.</p

Maximum voluntary force before and after 5 months of exercise.

<p>Maximum force at baseline and after the 5-month intervention for isometric low back extension (upper panel), lateral flexion to the left side (middle panel) and lateral flexion to the right side (lower panel) for the exercise and control group. Data are mean ± SE. * indicates p<0.05 for within-group differences (pre versus post-intervention) as analyzed with Students t-test for paired samples. The framed p-value represents the between-group differences (exercise- versus control group) over time as analyzed with an ANCOVA model.</p