Is home-based, high-intensity interval training cycling feasible and safe for patients with knee osteoarthritis? Study protocol for a randomized pilot study

Background - Osteoarthritis (OA) is a degenerative joint disease affecting the knee joint of many middle-aged and older adults. AsOA symptoms typically involve knee pain and stiffness, individuals with knee OA are often insufficiently physically active, have low levels of physical function, and are at increased risk of other comorbidities and reduced quality of life. While moderate-intensity continuous training (MICT) cycling is often recommended, little is known about the feasibility, safety, and benefits of high-intensity interval training (HIIT) cycling for this population, even though the feasibility, safety, and benefits of HIIT have been demonstrated in other chronic disease groups.
Purpose - The primary objective of this pilot study was to examine the feasibility and safety of home-based HIIT and MICT cycling in middle-aged and older adults with knee OA. A secondary objective was to gain some insight into the relative efficacy of HIIT and MICT for improving health status (pain, stiffness, and disability), muscle function, and body composition in this population. This study protocol is being published separately to allow a detailed description of the research methods, explain the rationale for choosing the methodological details, and to stimulate consideration of the best means to simulate a research protocol that isrelevant to a real-life treatment environment.
Study Design - Randomized pilot study protocol.
Methods - This trial sought to recruit 40 middle-aged and older adults with knee OA. Participants were randomly allocated to eithercontinuous (MICT) or HIIT home-based cycle training programs, with both programs requiring the performance of 4 cycling sessions(approximately 25 minutes per session) each week. Participants were measured at baseline and postintervention (8 weeks). Feasibilityand safety were assessed by adherence rate, dropout rate, and number of adverse events. The relative efficacy of the cycling programswas investigated by 2 knee OA health status questionnaires (Western Ontario and McMaster Universities Osteoarthritis Index scale[WOMAC] and the Lequesne Index) as well as the timed up and go, sit to stand, preferred gait speed, and body composition.Discussion:This pilot study appears to be the first study assessing the feasibility and safety of a home-based HIIT trainingprogram for middle-aged and older adults with knee OA. As HIIT has been demonstrated to be more effective than MICT forimproving aspects of health status, body composition, and/or muscular function in other chronic disease groups, the current studyhas the potential to improve patient outcomes and inform the design of future randomized controlled trials.Keywords:arthritis; cycling; exercise; function; pain; knee osteoarthritisOsteoarthritis (OA) is a degenerative joint disease affectingmany middle-aged and older adults. Recent global dataindicate that of the 291 conditions analyzed, hip and kneeOA was ranked as the 11th highest contributor to globaldisability and 38th highest in disability adjusted life years.8One of the most common sites for OA is the knee, withsymptoms including joint pain, tenderness, and reducedphysical function and mobility.18As a result of these symp-toms, many middle-aged and older adults with knee OA areless physically active than those without OA.24This redution in physical activity may further accelerate the age-related loss of muscle mass (especially around the kneejoint), muscle strength, and function seen in older adults,known as sarcopenia.9,10,44These knee OA–related losses