Knee Strengthening Exercises

Written By: Chloe Wilson, BSc(Hons) Physiotherapy
Reviewed by: KPE Medical Review Board

Knee strengthening exercises - beat knee pain fast

Knee strengthening exercises are one of the best ways to cure knee pain and stop it from coming back.

People who do knee strengthening exercises have less pain, recover quicker from injuries, function better and have less recurrences of pain.

Whenever there is weakness in the leg muscles, it means the knee joint is less well supported, resulting in more weight going through the bones and making knee problems much more likely. Knee strengthening exercises help to combat that1.

All the knee strengthening exercises here are easy to perform, quick, effective and suitable for most people, whether you are looking for exercises for runners, after an injury, with arthritis or almost any knee problem. The exercises are grouped into stages to help you work at the right level for you, whatever your starting point.

Why Should I Strengthen My Knees?

Having good knee strength and control is really important:

  • For knee stability & control
  • To ensure correct biomechanics in the feet, knee, hips and back
  • To reduce the risk of injury
  • To allow full, pain-free movement
  • To ensure full function

Best Exercises To Strengthen Knees

There are so many different knee strengthening exercises out there, it can be hard to know where to start. The best exercises to strengthen knees should include:

  • Quads Strengthening: Important for getting up from a chair, going upstairs, walking & running
  • Hamstring Strengthening: Important for running and twisting the knee
  • Glutes Strengthening: Weak glutes are one of the most common contributors to knee pain
  • Calf Muscle Strengthening: Important for controlling foot/ankle movement, standing on tiptoes
  • Balance & Stability Training: Really important for ensuring good control at the knee and preventing knee injuries
  • Vastus Medialis Strengthening: Really important for knee stability and control
  • Combination Knee Strengthening: Helps improve overall function at the knee

Related Article: Benefits of Resistance Bands >

Stage 1 Knee Strengthening Exercises

These stage 1 knee strengthening exercises are aimed at people who are in the early stages of recovery after a knee injury or knee surgery and are a great place to start.

They target the quadriceps, hamstring, glutes and calf muscles, and the great thing with these knee strengthening exercises is that they get the leg muscles working without needing the knee to move very much. This allows you to strengthen the knee muscles without aggravating the joint.

You may find that these exercises quickly become too easy, at which stage, move on to the stage 2 knee strengthening exercises below.

1. Quad Clenches

Purpose: Maintain and strengthen the Quads without moving the knee, enable full straightening of the knee. 

Starting Position: Lying flat on your back or sitting up. Leg and knee straight.

Action: Tighten the muscle on the front of the thigh by pushing your knee down. You should feel your thigh muscles clench. Hold for 3 secs.

Repetition: Repeat 10-20x every 3-4 hours.

Variations: If you are struggling to get your knee to straighten fully, place a rolled up towel underneath the ankle so that your leg is lifted slightly on the bed. Then do the exercise as described. Lifting the knee up slightly lets gravity help the knee to straighten.

2. Short Arcs

Purpose: Strengthen the quads muscles without much knee movement. Helps improve strength and control around the knee.

Starting Position: Lying flat on your back or sitting up with your leg horizontal on a flat surface such as a bed. Place a rolled up towel (approx 10cm diameter) under the knee.

Action: Pull your toes towards you and clench you thigh muscles. Slowly lift your foot up off the bed until your knee is straight (keep your knee resting on the towel). Hold for 3-5 secs and slowly lower.

Repetition: repeat 10-20 times, 3x daily.

Progression: 1) Increase the size of the towel under the knee
2) Add a weight e.g. by wearing a shoe, or using a light ankle weight. Progress further by using a heavier weight.

3. Hamstrings Clenches

Purpose: Strengthen the hamstrings muscles without having to move the knee

Starting Position: Sit in a chair with your heel against the leg of the chair and your feet firmly on the floor.

Action: Press your heel firmly backwards into the chair leg feeling the back of your thigh tightening/clenching. Hold for 3-5 secs.

Repetition: Do 10-20x, 2x daily.

Note: Your foot shouldn’t move during this knee exercise.

4.  Buttock Clenches

Purpose: Maintain and strengthen the glutes without the knee moving. Good glute strength is vital for knee stability.

Starting Position: Lying down or sitting up.

Action: Clench your buttocks together as tightly as you can and hold for 3 seconds. You should feel yourself rise up from the chair slightly.

Repetition: Repeat 10-20x every 3-4 hours.

Variation: If you find this uncomfortable, try doing this knee exercise lying down, either with your legs out straight or your knees bent.

5. Buttock Kicks

Purpose: Strengthen hamstrings without any weight going through the knee joint, increase knee mobility (flexion), aid circulation.

Starting Position: Lie on your tummy (on the floor or bed) with your legs straight.

Action: Lift your foot off the floor and bring it towards your bottom as far as you can. Slowly return to the starting position.

Repetition: Repeat 10-25x, 3x daily.

Notes: 1) You are aiming to get your heel all the way to your bottom 2) Make the exercise easier by hooking your good leg underneath the bad and using it to help lift the bad leg up.

Progression: Add a weight e.g. a shoe or ankle weight.

6. Heel Raises

Purpose: Strengthen the calf muscles to help support the knee, helps with standing, walking and running.

Starting Position: Stand with your feet slightly apart, weight equally distributed, holding onto something solid for balance if needed such as a chair or the wall.

Action: Rise up onto your toes lifting your heels as high as possible. Keep your body upright as you do this, don’t bend forwards. Hold for 3-5 secs and slowly lower.

Repetition: Repeat 10-30 times, 2x daily.

Top Tips: Try and push up equally through each leg.

Stage 2 Knee Strengthening

These stage 2 knee strengthening exercises are a little more challenging and not only get the leg muscles working, they also help to get the joints moving properly too.

Most of these knee strengthening exercises are done sitting or lying down so that there is no weight going through the knee joint. This means they are suitable for most people and don't aggravate any joint issues.

Again, you will get all the major muscle groups around the knee working with these knee strengthening exercises.

1. Straight Leg Raise

Purpose: Strengthen the Quads muscles without bending the knee. NB Do not do this if you have a history of back problems.

Starting Position: Lying flat on your back. Leg and knee to be worked straight, other leg bent.

Action: Pull your toes towards you and tighten/clench the muscle on the front of the thigh, locking your knee straight. Lift your foot up about 6 inches off the bed. Hold for 3-5 secs and slowly lower. Ensure your knee stays straight the whole time.

Repetition: repeat 10-20 times, 2x daily.

Progression: Add a weight e.g. by wearing a shoe.

2. Long Arcs

Purpose: Strengthen quads, increase knee mobility, great to do anytime sitting for prolonged periods (30mins+) to stop the knee getting stiff.

Starting Position: Sitting on a firm chair with your knee bent and your foot on the floor.

Action: Lift your foot up and straighten your knee as much as possible. Hold for 3-5 secs and slowly lower.

Repetition: 5-20 times, 3x daily.

Progression: Strengthen further by adding an ankle weight. 

3. The Clam: Stage 1

Purpose: Strengthen the glutes to help support the knee and prevent excessive weight going through the inner side of the knee – a must for anyone with knee pain!

Starting Position: Lie on your side with your hip and knees bent approx 90°, feet together.

Action: Keeping your feet together, lift the top knee up as high as you can. Hold for 3 seconds and slowly lower.

Repetition: Repeat 10-25x on each side, 2x daily.

Note: Do not let your top hip roll backwards.

Progression: Squeeze your heels together while doing the exercise to work the glutes harder.

4. The Bridge: Stage 1

Purpose: Bridging knee strengthening exercises the hamstring, quads and glutes all at the same time - it's like buy one get one (or two) free!

Starting Position: Lie on your back with both knees bent about 90° and your feet on the floor/bed.

Action: Clench your buttocks and lift your bottom off the bed as high as you can without arching your back. Hold for 3-5 seconds and slowly lower

Repetitions: Repeat 10-25 times, 1-2x daily.

Note: 1) Keep your back straight – don’t let it arch as you lift up, it should be your bottom doing the work 2) Don’t hold your breath – keep breathing normally.

5. Sit to Stand

Purpose: Improve knee mobility, strengthen quads and glutes, improve general fitness. This might not seem like a knee strengthening exercise to start with but believe me, once you've done a few repetitions you are going to feel this!

Starting Position: Sit in a firm chair, feet on the floor.

Action: Lean forwards, lift your bottom and stand up straight and then sit back down.

Repetition: Repeat 10-30x.

Notes: 1) You can make this exercise easier by pushing up through your arms too 2) The higher the chair, the easier the exercise.

Progression: 1) Don’t use your arms 2) Use a lower chair 3) Increase the speed you do knee strengthening exercises at 4) Hold a heavy weight – e.g. bag of books during this knee exercise.

6. One Leg Standing: Stage 1

One Leg Standing: Knee strengthening exercise. Approved Use by

Purpose: This one's all about balance. A quick test is to try standing on one leg with your eyes closed - it's harder than you might think! If you can’t do it for one minute, you should do some balance work alongside your knee strengthening exercises! 

Starting Position: Standing near a wall or chair for support.

Action: Lift up your good leg and stand on one leg for as long as you can.  It is normal to wobble a bit.

Repetition: Spend 5 minutes doing this 2x daily e.g. when brushing your teeth.

Progression: 1) Close your eyes and perform the exercise as above - you'll be surprised how much harder it is
2) Try Stage 2.

How Much Should I Do?

As your muscles get stronger, you will be able to increase the number of repetitions of each of these knee strengthening exercises.

You will probably need to do knee strengthening exercises at least four times a week for about a month before you notice much change in your knee pain at which point you may also want to add in some knee stretches -it's important to have enough strength before you start stretching else you can make things worse.

To find out how to exercise safely and effectively, visit the sections on How to Exercise Right and Getting the Best Results from your knee strengthening exercises. 

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Ready For More Of A Challenge?

Once you've mastered these knee strengthening exercises, you can move on to the next stage. In the intermediate knee strengthening exercises section, we build on the exercises you have done here and start adding in things like squats and step ups.

But it doesn't stop there! For those of you looking for high level rehab, in the advanced knee strengthening exercises we really go to town with different squat variations, lunges, box jump and plank work.

And if you are looking for a bit of variety, make sure you check out our article on the Benefits of Resistance Bands with exercises to see how you can switch things up!

If you are looking to specifically target one group of muscles, make sure you check out these:

And don't forget, muscles need good length as well as strength. People get most benefit from knee strengthening exercises when they are done along knee stretches.

Why Strengthen The Knee Muscles?

Good strength in the knee muscles is vital to allow not only the knee but the whole leg and lower back to work properly. Weakness in any of the knee muscles can lead to knee pain, increased risk of injury and joint degeneration.

The leg muscles need adequate strength and length and need to work together to ensure we can do all the activities we want.

  • Quads Strengthening: The quadriceps are the muscles at the front of the thigh that straighten the knee. Weak quads are one of the most common causes of knee pain making quads knee strengthening exercises an important part of any rehab programme.

  • Glutes Strengthening: The glutes are the buttock muscles, and they play a vital role in ensuring the forces go through the knee evenly. The glutes are often forgotten about in knee strengthening exercises.

    Virtually everyone who suffers from knee pain has weak glutes, so they are well worth doing. Indeed studies have shown that strengthening glute medius reduces pain and improves functional recovery following knee surgery2.

  • Hamstring Strengthening: The hamstrings are the muscles on the back of the thigh that bend the knee. You need a good combination of strength and length in these muscles. Hamstring knee strengthening exercises are particularly useful knee strengthening exercises for runners.

  • Knee Cap Strengthening: The VMO muscles control movement of the kneecap and are vital for stability and control. Almost everyone with knee pain ends up with weakness in their VMO, but traditional knee strengthening exercises fail to target this area.

  • Calf Strengthening: The calf muscles can be found on the back of the leg between the knee and the ankle. They move the foot and ankle, and help support the knee so should always been included with knee strengthening exercises.

Safety Advice

Remember, you should always check with your doctor before starting a new exercise programme, particularly if you have injured your knee, to ensure these knee strengthening exercises are safe to do.

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Page Last Updated: 08/10/20
Next Review Due: 08/10/22

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  5. Beginners Strengthening

Medical & Scientific References

1. Deconditioned Knee: The Effectiveness of a Rehabilitation Program that Restores Normal Knee Motion to Improve Symptoms and Function: K. Shelbourne, A. Biggs & T. Gray. North American Journal of Sports Physical Therapy, May 2007

2. The effect of gluteus medius strengthening on the knee joint function score and pain in meniscal surgery patients: Eun-Kyung Kim, PT, PhD. Journal of Physical Therapy Science, October 2016