Knee straightening is a simple knee rehab exercise. This exercise is performed on a chair. The movements performed in this exercise will not only help maintain the knee’s flexibility & its range of motion, but also strengthen both the knees & hips as well.

This is the second exercise in the Knee Strengthening Exercises series. The first exercise published in this series is Straight Leg Raise Exercise.

Purpose of This Exercise

This exercise will strengthen your knees and thigh muscles. It will also help improve the existing knee range of motion.

Continue reading here to learn how to perform Knee Straightening exercise perfectly with tips & VIDEO demonstrating it’s correct form, technique & proper movements.

How To Do Knee Extension Exercise (Knee Straightening) – Steps Wise Instructions

(i) Sit down in a chair with your hips & back against the back of the chair. Keep your knees at a 90° angle, resting your toes on the floor, hips-width apart. If your seat is not high enough, add pillow or other cushioning to heighten the chair. Rest your arms at your sides or on your thighs.

(ii) Slowly straighten your left leg as straight as you can, with the foot flexed.

(iii) When your leg is as high as you can lift it without pain, or when your leg is parallel to the floor, hold it for 2-5 seconds.

(iv) Slowly lower the leg down back to the starting position.

Note: Try to use full range of motion. You can ensure this by bringing your heel fully back as far as comfortable then extending (straightening) as far as comfortable.

(v) Now perform the same movement with you right leg without any jerk. This will complete one repetition (rep). Perform 10-12 reps. This will complete one set. Do the 2-3 sets as needed, resting for 30 to 60 between each set.

Make It More Challenging

If you desire so, you can make this exercise more challenging by wearing ankle weights. This will step up knee strengthening. Start with 2 pounds, and work your way up (if you desire so) by increasing weights for strengthening your knees more. As this process strengthens your quadriceps, your hamstring muscles also get an excellent stretch.


Inhale as you straighten the leg and exhale while lowering the leg down. Don’t hold breath during the exercise.


(i) If you want to engage your quadriceps more, try to bring your toes back toward your body.

(ii) Perform this exercise with the knee curl exercise because the muscles targeted, namely quadriceps & hamstrings, in these two exercises work together.

Watch this demo video to learn how to do Knee Extension Exercise? 

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