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6 of the best exercises to strengthen your knees

A photo of a woman performing a wall squat
(Image credit: SrdjanPav)

Whether you’re a runner, a cyclist, or a weight lifter, strong knees are important for performing at your best. But how can you strengthen your knees to avoid knee pain, and how often should you be adding these exercises to your training routine? Below, we’ve rounded up some of the best exercises to build strength in your knees. 

The knee is the largest joint in the body, and we use our knees every day for simple activities like walking or climbing stairs. As a result, knee injuries are common, and according to one study, runner’s knee is one of the most common sporting injuries out there. While it might be tempting to sit on the couch and put your feet up when you experience knee pain, this isn’t always the best solution. Instead, doing exercises that strengthen and support the knee can help alleviate knee pain, and prevent further injuries from occurring. 

Of course, it goes without saying that if you are experiencing severe pain in your knee, it’s worth checking with your doctor or physical therapist. If at any point you find one of the exercises on this list hurts your knee, stop immediately and try something else, or seek medical attention.

The best knee-strengthening exercises 

Knee strengthening exercises won’t strengthen the knee joint itself, rather the muscles surrounding it. Before practicing these exercises, it’s best to do a gentle warm-up, such as a walk, jog, or gentle cycle on a bike. 

an illustration of a woman doing a seated leg raise

(Image credit: Shutterstock)

1. Straight leg lifts 

To do this exercise, start by sitting straight in a chair, with your feet on the floor and your knees bent. Engaging the muscles in your thigh, lift one leg up until it is extended straight out in front of you, with your foot flexed and your toes pointing towards the ceiling. Hold at the top for a few seconds, before lowering your leg and repeating on the other side. 

This exercise targets your hamstrings. To increase the intensity, loop a resistance band around the ankle of the leg you are raising (we’ve found the best resistance bands for home workouts here), or add ankle weights to your legs. Alternatively, you can do the exercise lying on the floor, straightening the leg you are raising, and keeping the resting leg bent, with the foot pressed into your exercise mat (we’ve found the best yoga mats here). Start by doing three sets of 10 leg lifts on each side. 

an illustration of a woman doing a wall squat

(Image credit: Shutterstock)

2.  Wall squats  

Despite what you might think, squats are actually great for strengthening the knees and for your overall knee health. That said, they can put extra pressure on the knee joint if they are done with incorrect form, so wall squats are often a safe alternative. 

To do wall squats, stand with your feet hip-width apart, with your back flat against the wall. Your feet should be about two feet out from the wall. While keeping your back and shoulders pressed into the wall, squat down, until your knees are at around 90-degrees, as if you’re sitting in a chair. Pause for five seconds in the squat, before raising up to your starting position. 

This exercise targets the glutes and quads. Keep the exercise slow and controlled, and try and do three sets of 10 wall squats to start. 

an illustration of a woman doing a side leg lift

(Image credit: Shutterstock)

3. Side leg lifts 

Side leg lifts target the quads and the inner thighs. To do this exercise, start by lying on your side, with your legs and hips stacked on top of each other. Bracing your core, flex the foot of the top leg, and slowly raise it up towards the ceiling to about shoulder height. If you feel unbalanced, you might find it easier to slightly bend the lower leg. Pause at the top, before lowering the leg back down. Keep the entire movement slow and controlled, and aim for three sets of 10 leg lifts on each leg. 

To make the exercise harder, add a resistance band above the knees to increase the resistance, add ankle weights, or hold a dumbbell against the top leg as you raise and lower it. You can also increase the repetitions, or add some pulses to the top of the movement.

an illustration of a woman doing step-ups

(Image credit: Shutterstock)

4. Step-ups 

Step-ups are a brilliant way to strengthen your knees, as they target your quads, glutes, hamstrings, and hips. For this exercise, you’ll need a step, or box to step on to. 

To do a step-up, stand in front of a step, and put one foot onto the step, keeping the other on the ground. Engaging your glutes, step slowly up, keeping the leg stretched, and tap the foot onto the step, before slowly lowering back down. You can hold onto a wall or chair for support if you need it. To make the exercise harder, hold a dumbbell in each hand. Aim for three sets of 10 step-ups on each leg to start with. 

a photo of a woman doing calf raises

(Image credit: Shutterstock)

5. Calf raises  

As their name suggests, calf raises target the calf muscles. To do a calf raise, stand on a step or a box, with your feet hip-width apart. Put your weight forward onto your toes, and raise up onto your tip-toes. Pause at the top, and then lower back to your starting position. You might need to hold onto a wall or chair for support. 

To make the exercise harder, hold onto dumbbells in each hand, or a barbell on the back. Keep the entire movement slow and controlled, and start by doing three sets of 12 repetitions. 

an illustration of a woman doing hamstring curls

(Image credit: Shutterstock)

6. Hamstring curls  

Last, but by no means least, strengthen your hamstrings by doing hamstring curls. To do a hamstring curl, stand facing a chair, holding onto it for support. Flexing your foot, curl one leg up towards your bottom, keeping your thighs and knees in line with each other. 

To make the exercise harder, put a resistance band around your ankles, or add ankle weights. Aim for three sets of 12 hamstring curls on each leg. 

Looking for more workout inspiration? We've found the best ab workouts you can do for free, an exercise that’s better than squats at building your glutes, and one of the best ab exercises when it comes to sculpting a slimmer waistline.

Jane McGuire is Tom's Guide's Fitness editor, which means she looks after everything fitness related - from running gear to yoga mats. An avid runner, Jane has tested and reviewed fitness products for the past four years, so knows what to look for when finding a good running watch or a pair of shorts with pockets big enough for your smartphone. When she's not pounding the pavements, you'll find Jane striding round the Surrey Hills, taking far too many photos of her puppy.