BACKGROUND - Over 8.75 million people in the United Kingdom have painful osteoarthritis in one or both knees and a third of people of 45 years old have sought treatment. It has been well established that physical activity in mild - moderate osteoarthritis can provide improvement in symptoms and physical function. Current research is evaluating what modality of physical activity is best to achieve these improvements. A preliminary pedometer study in 2003 demonstrated symptomatic and functional improvement in knee osteoarthritis. A recent observational study has found that increased walking activity, with 6,000 steps per day being optimal, decreased the risk of functional limitation in knee osteoarthritis. Therefore, the purpose of this study is test evaluate the effectiveness of these recent recommendations against current UK physical activity guidelines.

AIMS - The study aims to investigate the role of walking in achieving a subjective improvement in symptomatic osteoarthritis of the knee/s. Furthermore, the study will investigate whether walking improves performance based tests which objectively assess physical function in participants with knee osteoarthritis. Null hypothesis to be tested: There is no difference in a 12 week intervention of walking 6,000 steps, per day, in improving pain and self reported physical function, compared to the current Department of Health physical activity guidelines.

EXPERIMENTAL PROTOCOL AND METHODS - Participants will be recruited through poster advertisement and non-incentivised involvement. Potential participants will be sent a Patient Information Leaflet for the study and a Consent Form. Following consent, the participant will be screened by telephone to ensure participants meet the inclusion criteria and also to exclude participants who would not be eligible on their medical history and activity status alone. Eligible participants from screening will be invited for a formal assessment. The assessment will confirm that information given in the screening remains accurate and a focussed physical examination of the knee. Participants eligible at the end of end of assessment will be randomly allocation into the control and intervention group, both lasting 12 weeks. Block randomisation will be used and this will be prepared by an independent person. Participants, irrespective of their allocation, will complete the following questionnaires: KOOS (KOOS: Knee Injury and Osteoarthritis Outcome Score), IPAQ (IPAQ: International Physical Activity Questionnaire), VAS for knee pain (VAS: Visual Analogue Scale), OKS (OKS: Oxford Knee Score), SF36 (SF36: Short Form Health Survey) and WOMAC (WOMAC: Western Ontario and McMaster Universities Arthritis Index). The intervention group will be allocated a walking activity of 6,000 per day. Participants will be provided with a pedometer and diary so walking activity can be recorded and monitored. Weekly scores will be collected via telephone contact with the participant. The control group will be provided with the standard physical activity advice that participants would receive from their GP (GP: General Practitioner) regarding physical activity levels. Both groups will complete a further IPAQ questionnaire at the mid point of the study at 6 weeks to monitor physical activity levels. At 12 weeks at the end of study, all participants will repeat the initial questionnaires, KOOS, IPAQ, VAS, OKS, SF36 and WOMAC and the performance based tests.

MEASUREABLE ENDPOINTS - Objective outcomes from performance based testing will be assessed, OARSI (OARSI: Osteoarthritis Research Society International) recommended physical function tests (6 minute walk test). Secondary outcomes: Pain, reported physical function in daily activities/sport/recreation, knee related quality of life measures from the above mentioned questionnaires and 4 other OARSI recommended functional tests (30sec chair stand test, 40m fast paced walk test, stair climb test and up and go test) in addition to age, sex, BMI (Body Mass Index), ethnicity and occupation.

N.B. 6,000 steps roughly equates to 2.5 miles/4.3 km. This distance is based on 71 steps to cover 100m (Investigator's 100m pace). At a steady pace, on flat terrain, 1 mile can be covered in 15minutes. The distance and timing to complete 6,000 steps will vary between participants depending on their stride length and pace.