Quadriceps Strengthening Exercises for Knee Osteoarthritis in Patients Over 50
All patients over 50 with knee osteoarthritis should perform quadriceps strengthening exercises as a core component of treatment, with specific exercises including quad sets, short-arc and long-arc quad sets, and closed-chain knee extensions performed 3-5 times daily. 1
Specific Exercise Protocols
Home-Based Quadriceps Exercises
The following exercises should be performed 5-7 repetitions, 3-5 times daily (before getting out of bed, before climbing stairs, and before going to sleep): 1
Quad Sets (Lying): Squeeze the thigh muscles on top of the thigh; hold for 6-7 seconds, then slowly relax; rest 2-3 seconds between squeezes 1
Short-Arc Quad Sets (Lying): Place a firm pillow under the knee so the knee is bent; slowly lift foot and straighten leg; hold for 6-7 seconds, then slowly relax; rest 2-3 seconds between motions 1
Long-Arc Quad Sets (Sitting): Keeping the back straight, slowly lift foot until leg is straight; hold for 6-7 seconds, then slowly lower leg; rest 2-3 seconds between motions 1
Closed-Chain Short-Arc Knee Extension (Standing): Slowly bend knees to 30 degrees, then slowly push back up, extending leg; rest 2-3 seconds between motions 1
Critical instruction: Never hold breath during any exercises. 1
Progressive Resistance Training Parameters
For more advanced strengthening, exercises should be performed at least 2 days per week at moderate to vigorous intensity (60-80% of one repetition maximum) for 8-12 repetitions. 2 Programs lasting 8-12 weeks with 3-5 sessions per week, each lasting 1 hour, produce the most effective outcomes. 3
Evidence for Effectiveness
Quadriceps strengthening produces statistically significant and clinically important effects on both pain and function. 1 The effect sizes for pain reduction range from 0.29-0.53, and for functional improvement from 0.24-0.58. 2, 3 All randomized controlled trials examining quadriceps strengthening in knee OA showed significant improvements in pain compared to control groups, with an effect size of 1.05. 2
Supervision and Program Structure
Twelve or more directly supervised sessions produce superior outcomes compared to fewer sessions, with pain improvement (effect size 0.46 vs 0.28) and physical function improvement (effect size 0.45 vs 0.23). 2, 3 Initial supervision by a physical therapist is strongly recommended to ensure proper technique and progression. 3
Dynamic strengthening exercises are more commonly studied and recommended than isometric exercises, though both can be effective. 2
Integration with Comprehensive Treatment
Quadriceps strengthening should be combined with: 1
- Low-impact aerobic exercise (walking, cycling, swimming) for 30-60 minutes daily at moderate intensity 3
- Weight loss counseling for patients with BMI ≥25 kg/m² 1
- Self-management education programs 1
Both land-based and aquatic exercise programs are equally effective; the choice should be based on patient ability and preference. 1 Aquatic exercise in warm water (86°F) is particularly beneficial for aerobically deconditioned patients, providing analgesia and reducing joint loading through buoyancy. 1
Common Pitfalls to Avoid
Avoid high-impact exercises, as the rate of joint loading (not just magnitude) is critical in producing pain or damage. 1 Patients should choose a variety of exercise options to prevent overuse of specific joints and avoid exercise boredom. 1
Do not discontinue exercises due to pain alone—clinical trials demonstrate that patients with pain and functional limitations benefit from exercise, with no uniformly accepted pain threshold that contraindicates exercise. 3 Even at 78 years of age, patients can achieve similar aerobic gains as younger adults with moderate-intensity training. 3