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 exercises here are easy to perform, quick, effective and suitable for most people, whether you are looking for knee strengthening exercises for runners, after an injury, with arthritis or almost any knee problem.

Why Do Knee Strengthening Exercises?

Knee strengthening exercises help to improve both the strength and control around the knee which 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

There are so many different knee strengthening exercises out there, it can be hard to know where to start. You will find a whole range of exercises here that will work all of the different muscle groups. Pick and choose three or four exercises that feel right for you - they should be challenging but not painful. You can even add resistance bands for more of a challenge!

Best Knee Strengthening Exercises

If you are looking for knee strengthening exercises after an injury or surgery, or you've never done exercises before, these are a good place to start. Once you feel confident with these, move on to the Intermediate and Advanced knee strengthening exercise sections or try some resistance bands exercises for knees.

1. Quad Clenches

The first of our knee strengthening exercises helps maintain and strengthen the quads muscles without moving the knee and helps enable full straightening of the knee. 

  • Lie flat on your back or sitting up. Leg and knee straight

  • 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.

  • Repeat 10-20x every 3-4 hours

  • 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

The Short Arcs knee exercise helps to strengthen the quads muscles without requiring much knee movement and improve control.

  • Lie 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

  • 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

  • repeat 10-20 times, 3x daily

  • You can challenge yourself further by
    a. Increasing the size of the towel under the knee 2)
    b. Add a weight e.g. by wearing a shoe, or using a light ankle weight
    c. Progress further by using a heavier weight.

3. Straight Leg Raise

This knee strengthening exercise works to strengthen the quads without needing to bend the knee. NB Do not do this if you have a history of back problems.

  • Lie flat on your back. Leg and knee to be worked straight, other leg bent

  • 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

  • Repeat 10-20 times, 2x daily

  • To work harder, add a weight e.g. by wearing a shoe.

4. Buttock Kicks

Buttock kicks are another great exercise to strengthen the hamstrings without any weight going through the knee joint. It also helps increase knee mobility (flexion) and aids circulation.

  • Lie on your tummy (on the floor or bed) with your legs straight

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

  • Repeat 10-25x, 3x daily

  • You are aiming to get your heel all the way to your bottom

  • Make the exercise easier by hooking your good leg underneath the bad and using it to help lift the bad leg up

  • Make the exercise harder by using a weight e.g. a shoe or ankle weight.

5. The Clam: Stage 1

The Clam is one of my absolute favourite knee strengthening exercises. It helps to strengthen the glutes to support the knee and prevent excessive weight going through the inner side of the knee – a must for anyone with knee pain! Works particularly well with resistance bands.

  • Lie on your side with your hip and knees bent approx 90°, feet together

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

  • Repeat 10-25x on each side, 2x daily

  • For more of a challenge, squeeze your heels together while doing the exercise to work the glutes harder

  • Do not let your top hip roll backwards.

6. The Bridge: Stage 1

The Bridge is one of those excellent knee strengthening exercises that works both the hamstrings, quads and buttock muscles. 3 for the price of 1! Also great with resistance bands.

  • Lie on your back with both knees bent about 90° and your feet on the floor/bed

  • 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

  • Repeat 10-25 times, 1-2x daily

  • Keep your back straight – don’t let it arch as you lift up, it should be your bottom doing the work 

  • Don’t hold your breath – keep breathing normally.

7. Hamstrings Clenches

Hamstring Clenches help to strengthen the hamstrings muscles without having to move the knee - again making them perfect after a knee injury or surgery.

  • Sit in a chair with your heel against the leg of the chair and your feet firmly on the floor

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

  • Repeat 10-20x, 2x daily

  • NB The foot shouldn’t move during this knee exercise.

8. Long Arcs

Long arcs helps to strengthen the quads, increase knee mobility and is great to do anytime sitting for prolonged periods, 30mins+, to stop the knee from getting stiff.

  • Sit on a firm chair with your knee bent and your foot on the floor

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

  • Repeat 5-20 times, 3x daily

  • Strengthen further by adding an ankle weight. 

9.  Buttock Clenches

Buttock clenches are the perfect place to start if you want to strengthen your glutes.

  • Start lying down or sitting up

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

  • Repeat 10-20x every 3-4 hours

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

10. Knee Marching

Knee Marching is one of those knee strengthening exercises that works the quads without having to put any weight through the knee joint, making it perfect in the early stages of recovery from a knee injury or surgery.

  • Sit in a chair with your feet on the floor

  • March your legs up and down one at a time. Lift your knee and foot up and then back down

  • Repeat for about 1 minute, 2x daily and any time you are sitting for more than 20 minutes to stop your knee getting stiff

  • Progress knee strengthening exercises by adding an ankle weight or shoe.

11. Kick Backs

The Kick Backs knee exercise helps to improve both the strength of hamstrings and the mobility of the knee.

  • Stand up straight holding on to something stable e.g. chair or table

  • Lift your foot up as far as you can towards your bottom, bending the knee. Hold for 3-5 secs

  • Repeat 5-25 times, 2x daily

  • For more challenge, add a weight e.g. shoe or ankle weight or use a resistance band

  • Don’t bend forwards - keep your body upright

  • Keep your knees in line with each other- don’t let your thigh come forwards.

12. Heel Raises

Heel Raises help to strengthen the calf muscles found on the back of the lower leg and particularly helps with walking and running. The calves move and control the foot and ankle, help support the knee and aid balance when standing on tip toes so should always been included with knee strengthening exercises. 

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

  • 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

  • Repeat 10-30 times, 2x daily

  • Try and push up equally through each leg.

13. Sit to Stand

Sit To Stand is another one of my favourite knee strengthening exercises! Whilst it might sound simple, this exercise helps to improve knee mobility, strengthens the quads, hamstring and glutes all at the same time, and improves general fitness and knee function.

I love knee strengthening exercises that work two or three muscle groups at the same time - it's like buy one get one (or two) free! 

  • Sit in a firm chair, feet on the floor

  • Lean forwards, lift your bottom and stand up straight and then sit back down

  • Repeat 10-30x

  • You can make this exercise easier by:
    a. pushing up through your arms too
    b. The higher the chair, the easier the exercise

  • You can make this exercise harder by:
    a. Not using your arms
    b. Using a lower chair
    c. Increasing the speed you do knee strengthening exercises at
    d. Hold a heavy weight – e.g. bag of books during this knee exercise.

14. One Leg Standing: Stage 1

Balance and stability are often affect by knee pain so it is really important to work on regaining both to ensure good control at the knee and help preventing further knee injuries.

A quick way to tell whether you should be doing balance exercises as part of your knee strengthening exercises program is to try standing on one leg with your eyes closed. If you can’t do it for one minute, you should do some balance exercises. 

One Leg Standing: Knee strengthening exercise. Approved Use by
  • Stand near a wall or chair for support

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

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

  • To work harder, close your eyes and perform the exercise as above - you'll be surprised how much harder it is. Or 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 or add in resistance bands to work the muscles harder.

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. 

When you feel ready, strengthen your muscles further by progressing on the intermediate and advanced knee strengthening exercises.

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Knee Strengthening Exercises By Muscle Group

Here we have looked at a range of knee strengthening exercises that work all of the different muscle groups working around the knee. If you would prefer to focus on one muscle group at a time, choose from these knee strengthening exercise programs.

  1. Quads Strengthening Exercises
    The quadriceps are the muscles at the front of the thigh that straighten the knee. Strong quads are important for getting up from a chair, going upstairs, walking & running. Weak quads are one of the most common causes of knee pain.

  2. Hamstring Strengthening Exercises
    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. The hamstrings are particularly important for running and twisting the knee.

  3. Glute Strengthening Exercises
    Weak glutes are one of the most common contributors to knee pain. The glutes are the buttock muscles, and they play a vital role in ensuring the forces go through the knee evenly but 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.

  4. Vastus Medialis Strengthening
    The vastus medialis muscles controls how the kneecap moves and is really important for knee stability and control. The muscle has to be worked in a different way to the other knee strengthening exercises.

Ready For More Of A Challenge?

Once you've mastered these knee strengthening exercises, you can move on to the next stage:

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.

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

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Page Last Updated: 07/12/23
Next Review Due: 07/12/25

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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