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The 7 Most Effective Exercises To Strengthen Weak Knees, Experts Say

Doing these movements daily will provide stability, enhance function, and lessen pain.
FACT CHECKED BY Alexa Mellardo

Knee problems can be caused by an injury or certain health issues, according to Mayo Clinic. Weak knees can create much havoc, as they can leave you unable to perform the tasks that are potentially required for both your job and daily life. Weak knees may also keep you from indulging in activities that bring you much joy. Fortunately, there are ways to strengthen weak knees, and we have the absolute best exercises for your workout routine.

Let's get started by understanding more about this crucial part of your body. "The knee is a joint that is inherently very mobile (lacking stability from its congruency) which allows for large ranges of motion making walking, squatting, lunging, etc. to be capable," Greg LeBlanc PT, DPT, OCS at Baton Rouge Physical Therapy-Lake, tells Eat This, Not That! LeBlanc continues to explain, "We gain some additional stability for the knee with our ligaments and muscles. Strong muscles act as shock absorbers for the knee joint during our normal functioning. [That's why, if] we can keep the muscles that surround and support the knee [strong, it] means less stress placed on the joint and ligaments." LeBlanc notes, "This can ultimately reduce pain and injury while improving function [and help you] avoid having weak knees."

LeBlanc suggests introductory movements "to help you strengthen the quadriceps, hamstrings, and hip muscles that surround and support your knee joint." He also notes doing these exercises on a daily basis will make the muscles surrounding your knee joint much stronger. This in turn will provide stability, enhance function, and lessen pain. So, read on to learn more about the most effective exercises to strengthen weak knees. And next, check out The 6 Best Exercises for Strong and Toned Arms in 2022, Trainer Says.

Quad Set

closeup woman doing quat set on yoga mat

Quad sets are integral in strengthening your knees. Your quads are so important and are involved in just about all of the movements in your legs. Quad sets will help make them flexible and also strengthen them.

"This exercise is an isometric contraction of your quadriceps muscle, which is in the front of your thigh," according to LeBlanc. "While this exercise seems very simple, it is very effective at strengthening the muscle and reestablishing the connection between your brain and the ability for your muscle to contract."

He continues to explain, "This exercise is completed while lying down on your back with your leg straight (the opposite leg is usually bent for comfort). While lying down, simply contract your quadriceps muscle as if you were completely straightening your leg or pushing the back of your knee into the surface you're lying on. Holding this contraction for a count of three to five seconds and completing 3 to 4 sets of 10 is the goal."

As for how often it should be done, LeBlanc says you can tackle this exercise once daily if you're not experiencing knee pain or injury.

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Straight Leg Raise

physical therapist helping patient do straight leg raise to strengthen weak knees

The straight leg raise will be extremely helpful in strengthening your muscle control. "The straight leg raise is a progression of the previously mentioned quad set," LeBlanc notes while adding, "[It] is also completed while lying on your back with one leg straight (opposite leg is bent for comfort)."

LeBlanc says that you should "initiate this exercise with a quad set, and then lift your leg approximately 12 inches off the ground while keeping your knee as straight as possible. Your straight leg will move to approximately the height of your opposite knee which should be bent."

Another exercise that should be done in 3 to 4 sets of 10 reps, it can be done once every day if you're not experiencing pain.

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woman doing glute bridge on yoga mat during barre workout

LeBlanc also suggests bridging to strengthen weak knees. He explains, "This exercise is aimed at targeting your hamstrings and gluteal muscles (hip muscles)."

You will lay on your back for this one, with both of your legs "bent to approximately 90 degrees," LeBlanc says. "From this starting position, the exercise is to lift your hips and low back off the surface."

LeBlanc notes, "[An] important aspect of this exercise is to ensure that your knees remain in good alignment with your feet making sure they don't drift towards each other (knock-kneed position) or too far outward (bow-legged position)." Once again, aim to do 3 to 4 sets of 10 once daily.


clamshell exercise to strengthen weak knees

When it comes to strengthening weak knees, an excellent and common exercise to focus on is the clamshell, as per LeBlanc. "This exercise is great for targeting your gluteal muscles or the muscles on the outside part of your hip."

To perform clamshells, LeBlanc says, "The starting position for this exercise is side-lying with your hips and knees each bent approximately 90 degrees. [From there, you'll want to] open your knees apart (while keeping your feet together) mimicking a clamshell opening." Stick with 3 to 4 sets of 10 once a day for this exercise.

To ensure that you don't hurt yourself, LeBlanc says, "[It] is important to take care and not allow your hips to roll backward while performing this exercise."

Related: The 5 Best Exercises To Build Calf Muscles Without Weights, Trainer Says

Mini Squat

woman doing a mini squat outside to strengthen weak knees

Mini squats are quite effective in making a lot of the muscles above work together, just the way they would function in everyday life, explains LeBlanc. He adds, "This exercise can be completed standing at a countertop." One great tip from LeBlanc? If you place a chair in the back of you, it's a perfect way to correct your performance and also stay safe while doing this exercise.

Knee Extensions

physical therapist helping patient do knee extension on table to strengthen weak knees

Jennifer Conroyd, founder of Fluid Running, a certified A.C.E. trainer, and U.S.A. track and field coach also offers some strengthening exercises for weak knees. Conroyd, who's an Ironman and has completed 16 marathons, qualifying for the Boston Marathon 15 times, tells Eat This, Not That!, "This exercise strengthens the quads and gives the hamstrings a nice stretch while allowing movement of the knee." An exercise to work into your day twice, if possible, you should shoot for 3 sets of 10 to 12 reps.

"Sit on a table or desk with your legs hanging over the edge," Conroyd says, adding that you then need to "place a thin pad or towel under your knee so that the knee is slightly higher than the hip." Following that, "extend the knee slowly with the foot flexed (toes toward you) until the leg is extended in front of you. Hold for three to five seconds, and then lower slowly." Add a light ankle weight if you want to up the difficulty of this exercise.


woman doing step-up exercise in gym to strengthen weak knees

Last but not least, step-ups are another one of Conroyd's suggestions, which she includes because they help strengthen the muscles that support your knees—your quadriceps, hamstrings, hips, and glutes.

"You will need a short platform, plyo box, or stair-step for this exercise," Conroyd says. "[To get started,] step onto the platform or stair with one foot, pressing through the heel, standing up tall with a straightened leg. [From there,] tap the platform or stair lightly with your other foot, then lower back down slowly, and repeat." To help with balance, Conroyd suggests, "You can hold the back of a chair, or place your hand on a wall." Noting that "you can work just one leg or alternate legs," this is an exercise that should involve 3 sets of 10 reps done twice each day.

To find out what might be causing your issues in the first place, be sure to read Walking Mistakes That Are Killing Your Knees, Experts Say. Then, don't forget to sign up for our newsletter for more of the latest mind and body news!

Desirée O
Desirée O is a freelance writer who covers lifestyle, food, and nutrition news among other topics. Read more about Desirée
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