Dose-Response Relationships of Resistance Training in Adults With Knee Osteoarthritis: A Systematic Review and Meta-analysis.

BACKGROUND AND PURPOSE: To determine the effects of resistance training (RT) on symptoms, function, and lower limb muscle strength in patients with knee osteoarthritis (KOA), and to determine the optimal dose-response relationships. DATA SOURCES: We searched the PubMed, MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and ClinicalTrials.gov databases from inception to January 23, 2022. ELIGIBILITY CRITERIA: Randomized controlled trials that examined the effects of RT in KOA patients (mean age ≥50 years) were included. DATA SYNTHESIS: We applied Hedges' g of the random-effects model to calculate the between-subject standardized mean difference (SMDbs). A random-effects metaregression was calculated to explain the influence of key training variables on the effectiveness of RT. We used the Grading of Recommendations Assessments, Development and Evaluation (GRADE) method to appraise the certainty of evidence. RESULTS: A total of 46 studies with 4289 participants were included. The analysis revealed moderate effects of RT on symptoms and function (SMDbs =-0.52; 95% CI: -0.64 to -0.40), and lower limb muscle strength (SMDbs = 0.53; 95% CI: 0.42 to 0.64) in the intervention group compared with the control group. The results of the metaregression revealed that only the variable "training period" (P< .001) had significant effects on symptoms, function, and lower limb muscle strength, and the 4 to 8 weeks of training subgroup showed greater effects than other subgroups (SMDbs =-0.70, -0.91 to -0.48; SMDbs = 0.76, 0.56 to 0.96). CONCLUSIONS: Compared with inactive treatments, RT is strongly recommended to improve symptoms, function, and muscle strength in individuals with KOA. Dose-response relationship analysis showed that 4 to 8 weeks of RT had more benefits.