Abstract: Twenty-one trials (2372 participants) met the inclusion criteria for quantitative synthesis. There were large variations in the exercise programme's content, mode of delivery, frequency and duration, participant's symptoms, duration of symptoms, outcomes measured, methodological quality and reporting. Comparator groups were varied and included normal care; education; and attention controls such as home visits, sham gel and wait list controls. Risk of bias was high in one and unclear risk in five studies regarding the randomisation process, high for 11 studies regarding allocation concealment, high for all 21 studies regarding blinding, and high for three studies and unclear for five studies regarding attrition. Studies did not provide information on adverse effects. There was moderate quality evidence that exercise reduced pain by an absolute percent reduction of 6% (95% confidence interval (CI) -9% to -4%, (9 studies, 1058 participants), equivalent to reducing (improving) pain by 1.25 points from 6.5 to 5.3 on a 0 to 20 scale and moderate quality evidence that exercise improved physical function by an absolute percent of 5.6% (95% CI -7.6% to 2.0%; standardised mean difference (SMD) -0.27, 95% CI -0.37 to -0.17, equivalent to reducing (improving) WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) function on a 0 to 100 scale from 49.9 to 44.3) (13 studies, 1599 participants)). Self-efficacy was increased by an absolute percent of 1.66% (95% CI 1.08% to 2.20%), although evidence was low quality (SMD 0.46, 95% CI 0.34 to 0.58, equivalent to improving the ExBeliefs score on a 17 to 85 scale from 64.3 to 65.4), with small benefits for depression from moderate quality evidence indicating an absolute percent reduction of 2.4% (95% CI -0.47% to 0.5%) (SMD -0.16, 95% CI -0.29 to -0.02, equivalent to improving depression measured using HADS (Hospital Anxiety and Depression Scale) on a 0 to 21 scale from 3.5 to 3.0) but no clinically or statistically significant effect on anxiety (SMD -0.11, 95% CI -0.26 to 0.05, 2% absolute improvement, 95% CI -5% to 1% equivalent to improving HADS anxiety on a 0 to 21 scale from 5.8 to 5.4; moderate quality evidence). Five studies measured the effect of exercise on health-related quality of life using the 36-item Short Form (SF-36) with statistically significant benefits for social function, increasing it by an absolute percent of 7.9% (95% CI 4.1% to 11.6%), equivalent to increasing SF-36 social function on a 0 to 100 scale from 73.6 to 81.5, although the evidence was low quality. Evidence was downgraded due to heterogeneity of measures, limitations with blinding and lack of detail regarding interventions. For 20/21 studies, there was a high risk of bias with blinding as participants self-reported and were not blinded to their participation in an exercise intervention. Twelve studies (with 6 to 29 participants) met inclusion criteria for qualitative synthesis. Their methodological rigour and quality was generally good. From the patients' perspectives, ways to improve the delivery of exercise interventions included: provide better information and advice about the safety and value of exercise; provide exercise tailored to individual's preferences, abilities and needs; challenge inappropriate health beliefs and provide better support. An integrative review, which compared the findings from quantitative trials with low risk of bias and the implications derived from the high-quality studies in the qualitative synthesis, confirmed the importance of these implications. Chronic hip and knee pain affects all domains of people's lives. People's beliefs about chronic pain shape their attitudes and behaviours about how to manage their pain. People are confused about the cause of their pain, and bewildered by its variability and randomness. Without adequate information and advice from healthcare professionals, people do not know what they should and should not do, and, as a consequence, avoid activity for fear of causing harm. Participation in exercise programmes may slightly improve physical function, depression and pain. It may slightly improve self-efficacy and social function, although there is probably little or no difference in anxiety. Providing reassurance and clear advice about the value of exercise in controlling symptoms, and opportunities to participate in exercise programmes that people regard as enjoyable and relevant, may encourage greater exercise participation, which brings a range of health benefits to a large population of people.

Plain-language summary: A search of medical databases up to March 2016 found 21 studies with 2372 people which considered pain, movement or both alongside psychological and social outcomes when people with pain and stiffness in their knee, hip, or both took part in exercise. Participation in exercise programmes probably slightly improves pain, physical function, depression, and ability to connect with others, and little or no difference in anxiety. It may improve belief in one's own abilities, and social function. The studies confirmed that: - people who exercised rated their pain to be 1.2 points lower on a scale of 0 to 20 after about 45 weeks (score: 5.3 with exercise compared with 6.5 with no exercise (control), an improvement of 6%). - physical function improved by about 5% over 41 weeks (exercise group improved by 5.6 points on a scale of 0 to 100 (44.3 with exercise compared with 49.9 with control)). - people's confidence in what they could do increased by 2% after 35 weeks (exercise group improved by 1.1 points on a scale of 17 to 85 (65.4 with exercise compared with 64.3 with control)). - people who exercised were 2% less depressed, or half a point on a scale of 0 to 21, after 35 weeks (3.0 points with exercise compared with 3.5 with control). - exercise made people feel less anxious about themselves by 2%, a 0.4 drop on a 0 to 21 scale, after 24 weeks (5.4 points with exercise compared with 5.8 with control). - exercise resulted in social interaction improving by 7.9 points over 36 weeks on a scale of 0 to 100, giving a change of 8% (81.5 with exercise compared with 73.6 with control). The quality of the evidence was generally moderate, but low for confidence in ability, mental health and social function. This is mainly due to varied measures, making comparison more difficult, and because people taking part knew they were exercising so may have been influenced by expectations of improvement. The studies did not report side effects. Studies lasted for different durations, so we do not know if changes occurred quickly and were maintained, or whether improvements were gradual throughout the studies. Some studies took measurements later after the programme than others. Additionally, 12 studies investigated people's opinions, beliefs and experiences of exercise, and whether exercise changed these. The quality of evidence was high overall. Initially people were confused about the characteristics of their pain, which shaped their feelings, behaviours and decisions about relieving pain. People thought movement and exercise was good for joints, but movement caused pain and they worried this might cause them harm. Lack of information from medical professionals meant people avoided physical activity and exercise for fear of causing damage. Overall, people who had taken part in exercise programmes had positive experiences, helping increase their beliefs that exercise could improve pain, physical and mental health, and general quality of life. Providing reassurance and exercise advice, challenging poor health beliefs, and providing enjoyable exercise programmes may encourage participation and benefit the health of many people.