Objective

This study investigates the effects of quadriceps isometric contraction training (QICT) on the symptoms, postural control, and movement ability of elderly women with knee osteoarthritis (KOA).

Methods

Forty-two older women with KOA were randomly divided into an experimental group (n = 21) and a control group (n = 21). All participants received the same health education for 16 weeks. The experimental group underwent QICT five times per week (contraction and relaxation for 5 s each, 30 repetitions per set, 10 sets, with a 30-s rest between sets). Assessments of KOA symptoms, postural control, and movement ability were performed at baseline and after the 16-week intervention.

Results

1) At the 16th week compared to baseline: The experimental group showed a 27.1% reduction in pain, a 13.8% reduction in stiffness, and a 15.7% reduction in functional impairment scores. The body sway index on a firm surface with eyes closed decreased by 14.3%. The knee extension peak torque at 180°/s increased by 31.6%, and the angle difference in the knee flexion proprioception test (30°) decreased by 24.5%. The 6MWT distance increased by 11.9%, and the time for the TUG decreased by 12.9% (P < 0.05). 2) At the 16th week, group comparisons showed that the experimental group had significantly lower pain scores, body sway index on a firm surface with eyes closed, and angle difference in the knee flexion proprioception test (30°) (P < 0.05), and significantly higher knee extension peak torque at 180°/s and 6MWT distance compared to the control group (P < 0.05).

Conclusion

Quadriceps isometric contraction training can significantly improve pain, stiffness, functional impairment, static balance ability, knee extension strength, and 6-min walk distance in older women with KOA, as well as enhance knee flexion proprioception. These results indicate that 16-week QICT is a safe and economical non-pharmacological intervention that can effectively improve the clinical symptoms and functional status of older women with KOA, providing a feasible treatment option for community and outpatient rehabilitation. Notably, the 31.6% increase in knee extensor peak torque (180°/s) exceeds the MCID (20%) for older adults with KOA, reflecting significant clinical benefits.