Therapeutic exercise
Seated Knee Extension
Open-kinetic-chain isotonic knee extension performed seated in a chair. Unlike the SLR (straight-leg raise), it isolates the quadriceps in end-range — useful in advanced knee osteoarthritis to recover pure extensor strength.
How to perform
- Starting position. Sit upright in a firm chair with the trunk supported, the feet flat on the floor, and the knees at 90 degrees.
- Step 2. Slowly extend one knee, raising the leg until it is parallel to the floor (quadriceps fully activated).
- Step 3. Hold the extended position for 2 to 3 seconds, feeling maximum quadriceps contraction.
- Step 4. Lower slowly over 3 seconds, returning to the starting position.
- Return. For progression, add ankle weights or an elastic band around the ankles. Alternate legs or complete a set on each.
When not to perform
- Patellar chondromalacia in acute inflammatory phase
- Recent ACL reconstruction (open-chain work is contraindicated in the first weeks)
- Recent femur or proximal tibia fracture
- Patellofemoral osteoarthritis with pain at end-range extension
- Recurrent patellar instability
- Anterior knee pain that flares with extension
Medical disclaimer. These exercises are presented for informational purposes only. Always consult your physician before starting any exercise program, especially in case of acute pain, recent injury, or underlying clinical condition.
Related Exercises
Quadriceps Isometric Sets
Isometric quadriceps activation without joint movement. Preserves strength without overloading the joint — a cornerstone of conservative treatment for knee osteoarthritis.
Straight-Leg Raise
Strengthens the quadriceps and hip flexors without bending the knee. Effective for moderate knee osteoarthritis when squats are contraindicated.
Mini Squat (0 to 45 Degrees)
Partial squat limited to the first 45 degrees of knee flexion, protecting the patellofemoral joint while recruiting quadriceps, glutes, and knee stabilizers. The exercise of choice in knee osteoarthritis and the early phase of meniscal or ligament rehab.