Considerations of the Principles of Resistance Training in Exercise Studies for the Management of Knee OA

The objective of this study was to evaluate the methodologic quality of resistance training interventions for the management of knee osteoarthritis. A search of the literature for studies published up to August 10, 2015, was performed on MEDLINE (OVID platform), PubMed, Embase, and Physiotherapy Evidence Database databases. Search terms associated with osteoarthritis, knee, and muscle resistance exercise were used.

Studies were included in the review if they were published in the English language and met the following criteria: (1) muscle resistance training was the primary intervention; (2) randomized controlled trial design; (3) treatment arms included at least a muscle conditioning intervention and a nonexercise group; and (4) participants had osteoarthritis of the knee. Studies using preoperative (joint replacement) interventions with only postoperative outcomes were excluded. The search yielded 1574 results. The inclusion criteria were met by 34 studies.

Two reviewers independently screened the articles for eligibility. Critical appraisal of the methodology was assessed according to the principles of resistance training and separately for the reporting of adherence using a specially designed scoring system. A rating for each article was assigned. There were 34 studies that described a strength training focus of the intervention; however, the principles of resistance training were inconsistently applied and inadequately reported across all. Methods for adherence monitoring were incorporated into the design of 28 of the studies, but only 13 reported sufficient detail to estimate average dose of exercise.

These findings affect the interpretation of the efficacy of muscle resistance exercise in the management of knee osteoarthritis. Clinicians and health care professionals cannot be confident whether nonsignificant findings are because of the lack of efficacy of muscle resistance interventions, or occur through limitations in treatment prescription and patient adherence. Future research that seeks to evaluate the effects of muscle strength training interventions on symptoms of osteoarthritis should be properly designed and adherence diligently reported.