How to strengthen your knees — 5 simple exercises that future proof your joints for life

Man with arms pressed on a wall left leg forward and right leg back in a high lunge
(Image credit: Getty images)

Your knees take a beating every day just from walking, with research showing the force on your joints equals one and a half times your body weight with each step. Add in a physical job, sports, or weight gain, and that stress adds up quickly.

After back pain, knee problems are one of the most commonly cited complaints, affecting mobility and quality of life. But strengthening the muscles around your knees can delay or prevent cartilage degeneration that leads to osteoarthritis and, in extreme cases, knee replacement surgery.

Spending 15 minutes three to four times per week on these movements helps protect your joints while improving balance and reducing fall risk. Here's what to do.

1. Step-ups

(Image: © Getty/JohnnyGreig)

Use a stair or a low step for this straightforward exercise. Push up with your preferred foot until both feet are on the step, then back down again. Alternate your lead foot with each rep.

Step-ups build your hamstrings and quadriceps using just your body weight. Strong quadriceps are particularly important since weak ones cause the kneecap to sit closer in, creating more rubbing and pain in the joint.

Start with two sets of 10 repetitions, resting between sets. The low-impact nature makes this accessible while still delivering strength benefits to key knee-supporting muscles.

2. Squats

(Image: © Getty)

Stand with feet shoulder-width apart and lower your body by bending your knees, keeping them aligned over your toes. Stop when your thighs are roughly parallel to the floor, then push back up.

Squats work both the quadriceps and gluteal muscles, which are critical for taking stress off the knee joint. They also improve proprioception, your body's awareness of where your joints are in space.

Squats improve bone mineral density and reduce fall risk in later life while stabilizing knees and reducing pain in arthritis patients.

3. Straight leg raises

(Image: © Liz Patient)

Lie on your back with one knee bent and foot flat on the floor. Keep your other leg straight and raise it off the ground, hold for a few seconds, then slowly lower it.

Contract your quadriceps muscle before lifting to engage the muscles you're targeting. This exercise strengthens the quads while protecting the joints and reducing the risk of exercise-related injuries when used as a warm-up.

Perform two sets of 10 reps per leg, alternating between legs. The controlled movement builds strength without putting stress directly on the knee joint itself.

4. Calf raises

(Image: © Getty/kali9)

Stand with feet shoulder-width apart and toes pointing forward. Slowly raise your heels while keeping your knees extended. Hold for one second on your toes, then lower back down.

Calf raises strengthen the gastrocnemius and soleus muscles in your calves, relieving stress from the knee joint below the kneecap. This improves muscle balance around your knee so all surrounding muscles work together efficiently.

Complete two sets of 10 raises to start. When one muscle group is weak, you create an imbalance that puts more strain on the knee joint itself.

5. Chair stands

(Image: © Getty Images)

Sit in a chair and stand up without using your hands for support, then sit back down. Repeat this movement for your target number of reps.

This exercise works your core muscles from mid-chest to your knees, which play an underrated role in maintaining knee health. Strong core muscles help stabilize your entire lower body.

You can also make it harder by using a lower chair or doing it one-legged as you get stronger. Start with two sets of 10 repetitions and adjust the difficulty based on your strength level.

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Kaycee Hill
How-to Editor

Kaycee is Tom's Guide's How-To Editor, known for tutorials that skip the fluff and get straight to what works. She writes across AI, homes, phones, and everything in between — because life doesn't stick to categories and neither should good advice. With years of experience in tech and content creation, she's built her reputation on turning complicated subjects into straightforward solutions. Kaycee is also an award-winning poet and co-editor at Fox and Star Books. Her debut collection is published by Bloodaxe, with a second book in the works.

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