Context: Dosing parameters are needed to ensure the best practice guidelines for knee osteoarthritis.
Objective: To determine whether resistance training affects pain and physical function in individuals with knee osteoarthritis, and whether a dose-response relationship exists. Second, we will investigate whether the effects are influenced by Kellgren-Lawrence grade or location of osteoarthritis.
Data sources: A search for randomized controlled trials was conducted in MEDLINE, Embase, and CINAHL, from their inception dates, between November 1, 2018, and January 15, 2019. Keywords included knee osteoarthritis, knee joint, resistance training, strength training, and weight lifting.
Study selection: Inclusion criteria were randomized controlled trials reporting changes in pain and physical function on humans with knee osteoarthritis comparing resistance training interventions with no intervention. Two reviewers screened 471 abstracts; 12 of the 13 studies assessed were included.
Study design: Systematic review.
Level of evidence: Level 2.
Data extraction: Mean baseline and follow-up Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and standard deviations were extracted to calculate the standard mean difference. Articles were assessed for methodological quality using the CONSORT (Consolidated Standards of Reporting Trials) 2010 scale and Cochrane Collaboration tool for assessing risk of bias.
Results: The 12 included studies had high methodological quality. Of these, 11 studies revealed that resistance training improved pain and/or physical function. The most common regimen was a 30- to 60-minute session of 2 to 3 sets of 8 to 12 repetitions with an initial resistance of 50% to 60% of maximum resistance that progressed over 3 sessions per week for 24 weeks. Seven studies reported Kellgren-Lawrence grade, and 4 studies included osteoarthritis location.
Conclusion: Resistance training improves pain and physical function in knee osteoarthritis. Large effect sizes were associated with 24 total sessions and 8- to 12-week duration. No optimal number of repetitions, maximum strength, or frequency of sets or repetitions was found. No trends were identified between outcomes and location or Kellgren-Lawrence grade of osteoarthritis.
Keywords: knee joint; knee osteoarthritis; resistance training; strength training; weight lifting.