Sixteen RCTs (1,162 participants) were included in the review. The mean score on the van Tulder scale was 6.9 (range 2 to 10); four RCTs were of high quality, seven were medium quality and five were low quality. Six RCTs were of sufficient quality to be included in meta-analyses. Follow-up ranged between one and three days and two and a half years.
Pain: Qualitative analysis suggested there was strong evidence that exercise was effective at reducing pain in the short-term (two out of four high quality RCTs) but quantitative analyses indicated no statistically significant differences in pain in the short-term between treatment groups (four RCTs); there was evidence of statistical heterogeneity (I²=87%).
Patient-reported function: Qualitative analysis suggested there was strong evidence that exercise was effective at improving patient-reported function in the short-term (two out of four high quality RCTs) and long-term (two out of four high quality RCTs). Quantitative analyses showed there were no statistically significant differences in short-term patient-reported function between treatment groups (five RCTs; I²=74%) but exercise had a small borderline statistically significant effect in the long-term (SMD -0.31, 95% CI -0.57 to -0.04; two RCTs; I²=0%).
Strength: Qualitative synthesis suggested that there was moderate evidence that exercise was effective in improving strength (two high quality RCTs) in the short term and quantitative analyses supported this (SMD -0.45, 95% CI -0.75 to -0.15; two RCTs; I²=0%).
Quality of life: Qualitative synthesis suggested there was moderate evidence that exercise was effective in improving and quality of life (one high quality RCT) in the short term but quantitative analyses did not support this (two RCTs; I²=41%).
Other results were reported in the review.