High- versus low-intensity resistance exercise in the treatment of pain in patients with knee osteoarthritis

Exercício resistido de alta versus baixa intensidade no tratamento da dor em pacientes com osteoartrite de joelho

Resumo

Objective: To compare the effects of two intervention protocols using a single low- (LIRE) or high- (HIRE) intensity resistance exercise on chronic pain and muscle strength in patients with knee osteoarthritis (KOA). Methods: Twenty patients with a clinical diagnosis of KOA were evaluated and randomized into two intervention groups: (HIRE: N=10, 75% of 1-RM; LIRE: N=10, 30% of 1-RM). Each group performed a single resistance exercise (knee joint extension on a leg extension machine) at high or low intensity twice a week. Strength for one repetition maximum (1-RM), functional strength, and pain were assessed before and after 12 weeks of intervention. Results: Pain decreased from pre- to post-test in both the ERBI group (effect size = -1.931) and the HIRE group (effect size = -3.299), and this reduction was significantly greater in the HIRE group (p > 0.05). Both HIRE and LIRE produced increases in 1-RM strength and functional strength after 12 weeks of intervention (p < 0.05). The percentage change between pre- and post-test for functional strength showed a negative correlation with the percentage change in pain only in response to high-intensity exercise (p < 0.05). Conclusions: ERAI is more effective than ERBI in reducing pain in patients with KOA. Increased functional strength is associated with greater pain reduction only in response to HIRE.