How To Strengthen Your Knees? | 6 Effective Exercises

Set of women doing air squat exercise to strengthen their knees

Knee pain accounts for nearly 4 million primary care visits annually.(1) The best way to exclude yourself from that statistic? Learn how to strengthen your knees.

You can easily strengthen your knee muscles at home with these 6 exercises. They’re versatile, and you can adapt them to your current level to reap the benefits!

I’ll also mention:

  • A few do’s and don’ts.
  • Other ways to strengthen the muscles around the knee.
  • Recommendations so you can get the best results!

Let’s get to it.

6 great knee strengthening exercises

1. Air squats

This exercise targets the quadriceps, the big muscle on top of your thigh. It straightens your leg and stabilizes the knee.

Some studies suggest that strengthening your quadriceps could also protect your cartilage from wear and tear, and:

“…quadriceps muscle strengthening has positive effects on (knee) pain and function.” – Turner, 2020

The easiest way to strengthen your quadriceps is by doing squats:

  • Stand with your feet shoulder-width apart. Point your toes slightly out.
  • Keeping your torso straight, slowly bend your hips. Imagine you’re doing a “sitting” motion by pulling your hips down and backward.
  • Descend until your hips are leveled with your knees.
  • Push yourself up while squeezing your glutes to get back to the starting position.

If this is too much for you, try these modifications:

  • Hold a chair to help you keep balance.
  • Squats on the wall.
  • Chair squats.
  • Leg raises.

2. Glute Bridge

This exercise helps you strengthen your glutes and hamstrings. When they’re strong, they can control your hip and knee joints to prevent injuries.

To do a glute bridge:

  • Lie on your back with your knees bent and your feet hip-width apart.
  • Keep your heels and toes firmly on the floor during the whole exercise.
  • Flatten your lower back. This will help you move from your hips and not from your spine.
  • Lift your hips from the floor, squeezing your glutes.
  • Slowly lower your hips to the starting position.

You might feel a stretch on the front side of your hips – this is probably your hip flexors stretching. As long as it’s not painful, don’t worry about it.

This exercise can also help you ease your lower back pain at the end of the day!

3. Hamstring curls

The hamstring muscles are the ones on the back of your thigh, from your buttock to the back of your knee. They help you bend your leg and stabilize the knee joint.

An easy way to strengthen these muscles is with a hamstring curl.

There are many ways to perform this, but here’s a home-friendly version:

  • Stand with your feet hip-width apart with your hands on the back of a chair to help your balance.
  • Slowly bend one knee until your heel is as close to your glute as it can be.
  • Slowly lower your foot.
  • Do a few reps and repeat with the other side.

To make sure you have a good form:

  • Keep your hips at the same level during each rep. If it’s hard for you to do this, it’s probably a sign of hip weakness. The side-leg raises below can help you with that.
  • Prevent your knee from moving forward during the exercise. Your thighs should be parallel with each other.

Using resistance bands or ankle weights can make the hamstring curls more challenging.

4. Calf raises

The calf muscles are, well, on the calves. They’re two muscle groups: the soleus and gastrocnemius.

They go from the back of your knee to your heel, forming the thick Achilles tendon.

To do a calf raise, just stand on your toes with your feet shoulder-width apart. Use a chair if needed to keep your balance.

You can make this exercise harder by standing on one leg at a time.

Another way to do it is by working with a stair-step:

  • Stand on a stair-step, with your heels over the edge.
  • Hold to the wall or railing if necessary to keep your balance.
  • Slowly lower your heels. You’ll probably feel a stretch on your calves at the end.
  • Slowly return to the initial position.

Doing calf raises with a straight leg will keep the focus on the gastrocnemius. On the other hand, bending your knee to 90° will shift the focus more on your soleus.

To keep these leg muscles healthy, do half of your sets with the leg straight, and the other half with the knee bent.

5. Side-leg raises

In this exercise, we’ll target the abductors – a group of muscles that go from the outer side of your hips to your knees.

They help you move your leg away from your body and stabilize your knee joint.

To perform a side leg raise:

  • Lie on your side. Stack up your hips and feet.
  • Use one arm to support your head.
  • Place the other arm in front of you, with your palm flat on the floor to help you keep balance.
  • Raise your top leg towards the ceiling.
  • Slowly lower it to the starting position.

If you’re finding it hard to keep your balance, you can:

  • Lie straight on your side with a wall behind you.
  • Bend the lower knee 90° while keeping the top knee straight.

Add some ankle weights to make it more challenging!

6. Side-lying hip adduction

We’ll work the adductors with this one. These are the muscles in the groin area, from your pubis to the inner side of your knee.

They help you squeeze your thigh muscles together and stabilize your knee.

In this exercise, you’ll feel the inside part of your thigh working. To do side-lying hip adduction:

  • Lie on your side, with the top knee bent 90° in front of you.
  • Keep the lower leg straight and point that foot straight during the whole exercise.
  • Lift the lower leg, keeping it straight.
  • Slowly, lower the leg to the starting position.
  • Do the number of repetitions and repeat on the other side.

Try not to move the straight leg forward or back while raising it.

To get better results…

If you have healthy knees, aim for 2-3 sets of 8-12 reps of each exercise. If you haven’t worked out in a while, start with one set and build up from there.

If you have osteoarthritis, try to do these exercises 3-5 times per week for 8-12 weeks. Studies suggest this can help you manage the knee pain and improve your knee function.(2)

Also:

  • Stop doing these exercises if they’re painful or you feel a sharp pain in your knees.
  • Don’t push through the pain or you risk getting injured.
  • Mild swelling is common, mostly if you haven’t exercised in a while. Too much swelling is a sign that you might be doing too much or there’s an injury.
  • Reduce the number of sets or repetitions if you have too much muscle soreness afterward.
  • Combine these exercises with good sleep and nutrition habits for best results.

If you aren’t sure whether you can do these exercises or not, consult with a physical therapist first.

What else can you do?

You can also strengthen the muscles of your legs with daily activities, like climbing stairs or walking more.

If you prefer more variety, some low-risk sports and activities could also help strengthen your knees:

  • Pilates.
  • Yoga.
  • Tai-chi.
  • Step-ups.
  • Using an elliptical machine.

Also, including a hamstring stretch – or any other stretch for that matter – can help you manage the muscle soreness post-exercise.

What are the benefits of knee strengthening exercises?

They can significantly reduce knee pain

Studies have shown that simple, home-based, knee strengthening exercises can significantly reduce knee pain – even after 2 years – compared to people who didn’t do leg exercises.(3,4)

The reduction in pain was greater the closer patients adhered to the exercise plan. – Thomas, 2002

They’re safe to do

Even for people with knee osteoarthritis!(2)

Also, these exercises can be modified to fit your physical capabilities. You can get stronger regardless of your starting point.

There are many ways to strengthen the muscles of your knees

So it comes down to your preferences, as research suggests:

Pilates, aerobic and strengthening exercise programmes performed for 8-12 weeks, 3-5 sessions per week; each session lasting 1 h appear to be effective. Both aquatic and land-based programmes show comparable and positive effects. – Raposo, 2021

FAQs:

What is the cause of weak knees?

Most of the time is a consequence of having a sedentary lifestyle. But, it can also be an early sign of knee arthritis.(5) It’s best to consult with your doctor or physical therapist to pinpoint the root cause.

How can I strengthen my unstable knees?

With a knee strengthening program adapted to the cause of the instability, your lifestyle, and goals. You could start with the exercises mentioned above, using a chair to help you keep balance.

If you have severe instability, please consult with your doctor or physical therapists before undergoing any new exercise program.

What is the best treatment for bad knees?

This will depend on the root cause of the knee problem. The general treatment usually involves some kind of physical therapy and knee exercises.

Is it safe for me to exercise?

Yes, if you are 18-50 years old without any medical condition.

If you have any of the following, it’s best to consult with your doctor before doing any new exercise program:

  • Pregnancy.
  • Chest pain.
  • Sickness or fever.
  • Heart disease or high blood pressure.
  • Diabetes.
  • Kidney disease.
  • Rheumatoid arthritis.

Conclusion: How to strengthen your knee?

By strengthening the muscles of your legs – not only the quadriceps.

By doing this, you’ll be able to do more activities you enjoy. Or make the ones in your daily life easier.

Whichever the case, you’ll only reap benefits from strengthening!

Resources

  1. Bunt, Christopher W et al. “Knee Pain in Adults and Adolescents: The Initial Evaluation.” American family physician vol. 98,9 (2018): 576-585. https://pubmed.ncbi.nlm.nih.gov/30325638/
  2. Raposo, Filipe et al. “Effects of exercise on knee osteoarthritis: A systematic review.” Musculoskeletal care, 10.1002/msc.1538. 5 Mar. 2021, doi:10.1002/msc.1538
  3. Thomas, K S et al. “Home based exercise programme for knee pain and knee osteoarthritis: randomised controlled trial.” BMJ (Clinical research ed.) vol. 325,7367 (2002): 752. doi:10.1136/bmj.325.7367.752
  4. Turner, Meredith N et al. “The Role of Resistance Training Dosing on Pain and Physical Function in Individuals With Knee Osteoarthritis: A Systematic Review.” Sports health vol. 12,2 (2020): 200-206. doi:10.1177/1941738119887183
  5. Hsu, Hunter, et al. “Knee Osteoarthritis.” [Updated 2020 Jun 29]. StatPearls. Retrieved on May 26, 2021 from: https://www.ncbi.nlm.nih.gov/books/NBK507884/