primary outcome:
Motor control exercise for chronic non‐specific low‐back pain
Pain intensity: all included trials measured pain intensity, except for one (Shaughnessy 2004). Pain was measured with a visual analogue scale (VAS) or numerical rating scale (NRS) in all trials. We converted all pain outcomes to a 0 to 100‐point scale.Disability: 13 trials measured disability using the Oswestry Disability Index (Franca 2010; Hemmati 2011; Inani 2013; Javadian 2012; Kachanathu 2012; Lomond 2015; Moon 2013; Rasmussen‐Barr 2003; Rasmussen‐Barr 2009; Rhee 2012; Stankovic 2012; Tsauo 2009; Unsgaard‐Tondel 2010). Nine trials used the Roland Morris Disability Questionnaire (Alp 2014; Cairns 2006; Costa 2009; Critchley 2007; Ferreira 2007; Koumantakis 2005; Macedo 2012; Puntumetakul 2013; Shaughnessy 2004), one trial used the Functional Rating Index Questionnaire (FRI) (Hosseinifar 2013), and one used the modified Oswestry Disability Index (MODI) (Rabin 2014). We converted all disability outcomes to a 0 to 100‐point scale.In total, we included 16 trials in this comparison (Akbari 2008; Cairns 2006; Critchley 2007; Inani 2013; Ferreira 2007; Franca 2010; Hosseinifar 2013; Javadian 2012; Kachanathu 2012; Koumantakis 2005; Lomond 2015; Macedo 2012; Miller 2005; Moon 2013; Stankovic 2012; Unsgaard‐Tondel 2010); three of them were at high risk of bias (n = 220) (Javadian 2012; Kachanathu 2012; Stankovic 2012). For the outcome pain, there is low quality evidence (downgraded due to risk of bias and publication bias) that there is a small, but not clinically important, effect of motor control exercise (MCE) for reducing pain at short‐term (mean difference (MD) –7.53; 95% confidence interval (CI) ‐10.54 to ‐4.52; P value < 0.001, 13 trials) compared with other exercises, and high quality evidence that there is no clinically important difference for pain at intermediate (MD –2.98; 95% CI –6.96 to 0.99, six trials) and long‐term follow‐up (MD –2.69; 95% CI –6.90 to 1.53, five trials) (Analysis 1.1).For disability, there is low quality evidence (downgraded due to risk of bias and publication bias) that there is a small, but not clinically important, effect on improving disability at short‐term follow‐up (MD –4.82; 95% CI ‐6.95 to ‐2.68; P value < 0.001, 11 trials), and high quality evidence for no clinically important difference at intermediate (MD –2.88; 95% CI –6.92 to 1.15, 10 trials) and long‐term follow‐up (MD –0.71; 95% CI –4.87 to 3.45, four trials) (Analysis 1.2).We included a total of five trials with low risk of bias in the meta‐analysis (Critchley 2007; Ferreira 2007; Goldby 2006; Rabin 2014; Rasmussen‐Barr 2003). For the outcome pain, there is moderate quality evidence (downgraded due to imprecision) that there is no clinically important effect of MCE compared to manual therapy at short (MD –4.36; 95% CI –9.52 to 0.81; P value = 0.10, three trials) and intermediate‐term follow‐up (MD –7.05; 95% CI –14.20 to 0.11; P value = 0.05, four trials), and there is high quality evidence for long‐term follow‐up (MD –3.67; 95% CI –9.28 to 1.94, four trials) (Analysis 2.1). We cannot discard an important effect for pain at intermediate term as the confidence interval includes a clinically important effect.For disability, there is moderate quality evidence (downgraded due to imprecision) that there is no clinically important difference at short‐term follow‐up (MD –2.79; 95% CI –6.60 to 1.02, three trials), and high quality evidence for intermediate (MD –3.28; 95% CI –6.97 to 0.40, four trials) and long‐term follow‐up (MD –3.40; 95% CI –7.87 to 1.07, four trials) (Analysis 2.2).We included seven trials in the meta‐analysis for this comparison (Costa 2009; Goldby 2006; Hemmati 2011; Rasmussen‐Barr 2009; Rhee 2012; Shaughnessy 2004; Tsauo 2009); two of them (n = 66) with a high risk of bias (Shaughnessy 2004; Tsauo 2009). For the outcome pain, there is moderate quality evidence (downgraded due to imprecision) that there is a clinically important effect of MCE for reducing pain with medium effect size at short‐term (MD –10.01; 95% CI –15.67 to –4.35; P value < 0.001, four trials) and long‐term follow‐up (MD –12.97; 95% CI –18.51 to –7.42; P value < 0.001, three trials). There is low quality evidence (downgraded due to inconsistency and imprecision) for a clinically important effect in favour of MCE in the intermediate term, with a medium effect size (MD –12.61; 95% CI –20.53 to –4.69; P value = 0.002, four trials) (Analysis 3.1).For disability, there is very low quality evidence (downgraded due to risk of bias, inconsistency and imprecision) that there is a small, but not clinically important, effect on MCE for improving disability at short‐term follow‐up (MD –8.63; 95% CI –14.78 to –2.47; P value < 0.01, five trials); however we cannot discard an important effect as the confidence interval includes a clinically important effect.There is moderate quality evidence (downgraded due to imprecision) that there is no clinically important effect at intermediate (MD –5.47; 95% CI –9.17 to –1.77; P value = 0.004, four trials) and long‐term follow‐up (MD –5.96; 95% CI –9.81 to –2.11; P value = 0.002, three trials), with small effect sizes (Analysis 3.2).We included three trials with low risk of bias in the meta‐analysis for this comparison (Kumar 2009; Kumar 2010; Puntumetakul 2013). The treatment programme included in this comparison comprises a combination of ultrasound, short‐wave diathermy and lumbar strengthening exercises in two trials (Kumar 2009; Kumar 2010), and active trunk stretching exercises plus heat application in another trial (Puntumetakul 2013).There is low quality evidence (downgraded due to imprecision and indirectness) that there is a clinically important effect of MCE for reducing pain at short‐term follow‐up compared with exercise and electrophysical agents (EPA), with a large effect size (MD –30.18; 95% CI –35.32 to –25.05, P value < 0.001, two trials) (Analysis 4.1). We did not pool results for intermediate‐term follow‐up due to high heterogeneity, but these are presented descriptively. Two studies reported a clinically important difference in favour of MCE compared with exercise and EPA, with very low quality evidence for this comparison (downgraded due to inconsistency, imprecision and indirectness).For disability, based on one trial and very low quality evidence (downgraded due to imprecision, indirectness and inconsistency) there is a clinically important effect in favour of MCE at short‐term follow‐up with large effect size (MD –20.83; 95% CI –28.07 to –13.59, P value < 0.001) and there is low quality evidence (downgraded due to inconsistency and imprecision) for an intermediate‐term effect, with medium effect size (MD –11.50; 95% CI –20.69 to –2.31, P value = 0.01, one trial) (Analysis 4.2).