Abstract: We included 29 trials (n = 2431) in this review. The study sample sizes ranged from 20 to 323 participants. We considered a total of 76.6% of the included trials to have a low risk of bias, representing 86% of all participants. There is low to high quality evidence that MCE is not clinically more effective than other exercises for all follow-up periods and outcomes tested. When compared with minimal intervention, there is low to moderate quality evidence that MCE is effective for improving pain at short, intermediate and long-term follow-up with medium effect sizes (long-term, MD –12.97; 95% CI –18.51 to –7.42). There was also a clinically important difference for the outcomes function and global impression of recovery compared with minimal intervention. There is moderate to high quality evidence that there is no clinically important difference between MCE and manual therapy for all follow-up periods and outcomes tested. Finally, there is very low to low quality evidence that MCE is clinically more effective than exercise and electrophysical agents (EPA) for pain, disability, global impression of recovery and quality of life with medium to large effect sizes (pain at short term, MD –30.18; 95% CI –35.32 to –25.05). Minor or no adverse events were reported in the included trials. There is very low to moderate quality evidence that MCE has a clinically important effect compared with a minimal intervention for chronic low back pain. There is very low to low quality evidence that MCE has a clinically important effect compared with exercise plus EPA. There is moderate to high quality evidence that MCE provides similar outcomes to manual therapies and low to moderate quality evidence that it provides similar outcomes to other forms of exercises. Given the evidence that MCE is not superior to other forms of exercise, the choice of exercise for chronic LBP should probably depend on patient or therapist preferences, therapist training, costs and safety.

Plain-language summary: In total, 2431 participants were enrolled in 29 trials. The study sample sizes ranged from 20 to 323 participants, and most of them were middle-aged people recruited from primary or tertiary care. The duration of the treatment programmes ranged from 20 days to 12 weeks, and the number of treatment sessions ranged from one to five sessions per week. Sixteen trials compared MCE with other types of exercises, seven trials compared MCE with minimal intervention, five trials compared MCE with manual therapy, three trials compared MCE with a combination of exercise and electrophysical agents, and one trial compared MCE with telerehabilitation based on home exercises. MCE probably provides better improvements in pain, function and global impression of recovery than minimal intervention at all follow-up periods. MCE may provide slightly better improvements than exercise and electrophysical agents for pain, disability, global impression of recovery and the physical component of quality of life in the short and intermediate term. There is probably little or no difference between MCE and manual therapy for all outcomes and follow-up periods. Little or no difference is observed between MCE and other forms of exercise. Given the minimal evidence that MCE is superior to other forms of exercise, the choice of exercise for chronic LBP should probably depend on patient or therapist preferences, therapist training, costs and safety.