Exercise reduces pain in adults with chronic non-specific low back pain

Low-back pain is the leading cause of disability globally. The large volume of research on it has failed to reach a consensus on the best treatment approach for people with chronic non-specific low-back pain. This systematic review estimated the effects of exercise therapy on pain and functional limitations in people with chronic non-specific low-back pain.

Guided by a prospectively registered protocol, sensitive searches were performed in seven databases (including Cochrane Central Register of Controlled Trials, Medline and PEDro) and two trial registries to identify randomised controlled trials evaluating exercise therapy for people with low-back pain (date of search: 27 April 2018). 

The population was adults with non-specific low-back pain of more than 12 weeks’ duration. Trials that recruited participants with symptoms or signs consistent with radiculopathy (such as leg pain) were included if back pain was their main complaint. 

Exercise therapy

Exercise therapy was classified as strengthening, stretching, core strengthening, flexibility/mobilising, aerobic, functional restoration, McKenzie therapy, yoga, mixed, and other. 

The comparator could be no treatment (including no or minimal treatment, usual care or placebo), other conservative treatments (including education, manual therapy, electrotherapy, psychological therapy, non-exercise physiotherapy, back school, relaxation, anti-inflammatory medication) or another type of exercise therapy. However, comparisons between different types of exercise therapy were not undertaken in this review. 

The primary outcomes were pain and functional limitations measured on any scale, and data were re-scaled to a 0-to-100-point scale (where 0 is no pain or functional limitations) for the analyses. A 15-point difference in pain and a ten-point difference in functional limitations were pre-specified to be clinically important. If outcomes were evaluated at multiple time points, data from the earliest time point after randomisation was used in the primary analyses. Two independent reviewers selected trials for inclusion and evaluated trial quality, and disagreements were resolved by discussion or by arbitration from a third reviewer. Data were extracted by one reviewer and checked by at least one other reviewer. 

Trial quality was evaluated using version 1.0 of the Cochrane risk of bias tool. The grades of recommendation, assessment, development and evaluation approach were used to evaluate certainty of evidence. Meta-analysis was used to pool trials and calculate the mean between-group difference, and the associated 95 per cent confidence interval (CI), for pain and functional limitations. Separate comparisons were performed for trials using no treatment and other conservative treatments.

A systemic review

The review included 249 trials (24,486 participants). Most trials were conducted in Europe (122 trials), Asia (38), North America (33) and the Middle East (24). The average age of participants was 44 years and 59 per cent were women. At baseline, participants reported a mean pain intensity of 51 points and functional limitations of 38 points. There were 142 trials comparing exercise therapy to no treatment or other conservative care while 151 trials compared the effects of two or more different types of exercise therapy. Most exercise therapy involved a mixed type of exercise (110 trial groups). The most common specific types were core strengthening (131), Pilates (29), general strengthening (57), stretching (51), and aerobic (41).

Compared with no treatment (including no or minimal treatment, usual care or placebo), exercise therapy reduced pain by a mean of 15 points (95 per cent CI 18 lower to 12 lower; 35 trials; 2,746 participants; moderate certainty) and reduced functional limitations by a mean of seven points (95 per cent CI eight lower to five lower; 38 trials; 2,942 participants; moderate certainty). 

This difference in pain was clinically important based on pre-specified criteria, but the difference in functional limitations was not.

Compared with other conservative care, exercise therapy reduced pain by a mean of nine points (95 per cent CI 13 lower to six lower; 64 trials; 6,295 participants; low certainty) and functional limitations by a mean of four points (95 per cent CI six lower to two lower; 52 trials; 6,004 participants; moderate certainty). These differences were not considered to be clinically important.

Conclusion

Exercise therapy most likely reduces pain when compared to no treatment in people with chronic, non-specific low-back pain. The impact of exercise therapy on functional limitations when compared with no treatment and on pain and functional limitations when compared with other conservative care are probably small. 

Citations
Citation: Hayden JA, et al. Exercise therapy for chronic low back pain. Cochrane Database Syst Rev 2021; Issue 9