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. As OA 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 is relevant 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 either continuous (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). Feasibility and safety were assessed by adherence rate, dropout rate, and number of adverse events. The relative efficacy of the cycling programs was 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 training program for middle-aged and older adults with knee OA. As HIIT has been demonstrated to be more effective than MICT for improving aspects of health status, body composition, and/or muscular function in other chronic disease groups, the current study has the potential to improve patient outcomes and inform the design of future randomized controlled trials.