What exercises are recommended for knee osteoarthritis (OA) management?

Exercise Recommendations for Knee Osteoarthritis

All patients with symptomatic knee osteoarthritis should participate in a structured exercise program combining both strengthening exercises (particularly quadriceps strengthening) and low-impact aerobic activities, performed at moderate intensity for at least 30 minutes per day, 3-5 times per week. 1, 2

Core Exercise Components

Strengthening Exercises

• Quadriceps strengthening is essential and demonstrates significant pain reduction (effect size 0.29-0.53) and functional improvement (effect size 0.24-0.58) in knee OA. 1
• Perform progressive strength training involving major lower limb muscle groups at moderate to vigorous intensity (60-80% of one repetition maximum) for 8-12 repetitions, at least 2 days per week. 1
• Specific home-based quadriceps exercises include: quad sets (lying), short-arc quad sets (sitting with pillow under knee), long-arc quad sets (sitting), gluteal squeezes, and closed-chain short-arc knee extensions (standing). 1
• Each exercise should be performed 5-7 times, 3-5 times daily, holding contractions for 6-7 seconds with 2-3 seconds rest between repetitions. 1
• Dynamic exercises are preferred over isometric exercises based on available evidence. 1

Aerobic Exercise

• Low-impact aerobic activities are strongly recommended with demonstrated pain relief (effect size 0.52) and disability reduction (effect size 0.46). 1, 2
• Acceptable modalities include walking, cycling, swimming, low-impact aerobics, tai chi, treadmill, or rowing machines. 1
• Perform moderate-intensity aerobic training for at least 30 minutes per day (up to 60 minutes for greater benefit), most days of the week. 1, 2
• Aquatic exercises in warm water (86°F) are particularly beneficial as buoyancy reduces joint loading while providing pain relief. 1, 2

Range-of-Motion and Flexibility

• Range-of-motion exercises address joint stiffness and limited motion commonly seen in knee OA. 1, 2
• These exercises should focus on gentle stretching of muscles around the knee joint. 2
• Perform these exercises regularly as part of the comprehensive program. 1

Implementation Strategy

Supervision and Frequency

• Initial supervised instruction is critical: 12 or more directly supervised sessions produce significantly better outcomes than fewer sessions (pain effect size 0.46 vs 0.28; function effect size 0.45 vs 0.23). 1, 2
• After initial supervision, patients should integrate exercises into daily life for long-term maintenance. 1
• Exercise should be performed at least 3 times per week, with progression in intensity and duration over several months. 2, 3
• Moderate-intensity exercise performed 3 times weekly for 20-60 minutes appears optimal for symptom control. 3

Progression

• Progressive overload is essential: intensity, frequency, and volume must gradually increase beyond normal daily activities. 1
• Strength training should include progressive increases in resistance over time. 1
• For aerobic conditioning, apply the overload principle by gradually increasing duration and intensity to improve VO2max. 1

Adjunctive Interventions

Weight Management

• Weight loss is strongly recommended for overweight patients (BMI >25): minimum 5% body weight reduction produces clinically important functional improvement (WOMAC function effect size 0.69). 1, 2
• Combine dietary modification with exercise for optimal results. 1, 2
• Weight-loss programs with explicit goals achieve mean reductions of 4.0 kg compared to 1.3 kg without explicit goals. 1

Self-Management Education

• Participation in self-management programs is conditionally recommended for goal-setting, problem-solving, and coping strategies. 1, 2
• These programs demonstrate small but significant improvements in pain and function (effect sizes 0.02-0.10). 1

Additional Modalities

• Tai chi programs show growing evidence for pain reduction (effect sizes 0.28-1.67) and can be incorporated. 1
• Manual therapy combined with supervised exercise is conditionally recommended. 1
• Appropriate footwear with shock-absorbing insoles may reduce pain and improve function. 1

Critical Caveats

Safety Considerations

• Pain during exercise should not prevent participation: clinical trials demonstrate improvements even in patients experiencing pain during exercise. 2
• High-impact exercises should be avoided as they may accelerate joint damage. 2
• Exercise programs should be modified if they significantly exacerbate pain, shifting focus to gentler low-impact activities. 2
• Never hold breath during exercises to avoid Valsalva maneuver. 1

Special Populations

• Elderly patients and those with severe OA benefit equally from exercise programs. 3
• In severe knee OA, walking may only prevent deterioration rather than induce symptomatic improvement; consider aquatic or cycling alternatives. 3
• Patients with multiple medical comorbidities should be referred to experienced physical therapists for individualized program design. 1

Comparative Effectiveness

• No single exercise modality is superior: strength training and aerobic training produce comparable improvements in pain and function (no significant difference between groups). 3, 4
• Both aquatic and land-based programs show similar positive effects. 1, 5
• Any dose of regular exercise is effective, though moderate intensity 3 times weekly for 20-60 minutes appears optimal. 3