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Patellofemoral pain syndrome (runner’s knee)

Patellofemoral pain syndrome (runner’s knee)

Seven exercises to stabilize the knee

Photo of an athletic man holding his knee in pain

Strengthening the thigh and hip muscles can help to relieve pain in the front part of the knee. Here we describe seven suitable exercises that you can easily do in everyday life.

Strong muscles protect the knees by stabilizing the axis (alignment) of the legs. The hip, knee and ankle joint are usually positioned above and below each other in a straight vertical line. That puts the optimal amount of strain on the kneecap. If the muscles are weak, the pelvis may tilt and the knees and feet might lean inward. The exercises described below are suitable for strengthening these muscles.

Ideally you should do the exercises every two days. The instructions about sets of exercises and repetitions are meant to act as a guide only. The number of exercise sets you do will depend on your personal situation – for instance, how fit you are. The number of repetitions you do isn't as important as doing the exercises in a controlled way. Although the last repetition should be strenuous, you should still be able to do it properly. You can use the following as a general guide: Do 10 repetitions of each exercise on either side, and gradually increase to 20 repetitions – keeping the same total number of exercise sets.

If the front knee pain is severe, it’s a good idea to only do exercises for the hip muscles first (like the first two described here) and then add the knee exercises when the pain has become milder.

Side leg raises

  • Lie on your side on an exercise mat with your legs stretched out.
  • Rest your head on your arm, which can either be bent or stretched out.
  • Place the hand of your other arm on the floor in front of your belly to stabilize your upper body.
  • Lift your top leg sideways towards the ceiling, briefly hold it there, and then lower it again.
  • Repeat this exercise 10 to 20 times. Do the same using the other leg. Do a total of 3 sets of repetitions for each leg.
  • Make sure you keep your body stable and carry out the movements slowly and in a controlled way. Your upper body shouldn’t move when your leg moves.
  • If you would like to do a more challenging exercise, you can put an elastic band around your knees. It should be placed just above the knee joint.
Illustration: Side leg raises

This exercise strengthens the hip abductor muscles – the muscles that let you move your thigh sideways.

Side-lying clam exercises

  • Lie on your side on an exercise mat, keeping your upper body straight.
  • Rest your head on your arm, which can either be bent or stretched out.
  • Place the hand of your other arm on the floor in front of your belly to stabilize your upper body.
  • Place the top leg and foot on top of the other, and bend your legs so your thigh and lower leg are at a right angle (90 degrees).
  • Now slowly lift your top leg toward the ceiling and lower it again, keeping your feet together the whole time. Only lift the knee as far as you can without moving the rest of your body.
  • Repeat 10 to 20 times. Change sides. Do 3 sets in total.
  • If you would like to do a more challenging exercise, you can put an elasticated band around your knees. It should be placed just above the knee joint.
Illustration: Side-lying clam exercises

This exercise strengthens the hip abductor muscles and the hip external rotation muscles. It is important to keep your upper body still while doing clam shell exercises – in other words, make sure your pelvis and back don’t tilt forwards or backwards. To help prevent your body from moving, you can also lean your back against a wall while doing the exercises.

Straight leg raises

  • Lie on your back on an exercise mat with both legs stretched out.
  • Bend your right leg at a 90-degree angle, putting your foot flat on the floor.
  • Now slowly lift your left leg up off the floor until it’s at a 45-degree angle to the floor (see illustration). Hold it in the air for five seconds and then slowly lower it to the floor again.
  • Repeat 10 to 20 times and then change sides: bend your left leg and place your left foot flat on the floor, lift your right leg. Do a total of 3 sets.
  • While doing these exercises, try to keep your back flat on the ground, pull your belly button in slightly and carry out the movements slowly and in a controlled way, especially when lowering the leg.
Illustration: Straight leg raises

This exercise strengthens the core muscles and the muscle at the front of the thigh (quadriceps).

Leg extensions while sitting

  • Sit on a chair or stool that is high enough for you to bend your legs at a right angle (90 degrees).
  • You can wear a light weight cuff on your lower leg (above the ankle) if you like.
  • Slowly stretch out one leg in front of you and lift it up, then slowly bend and lower it. It should take about 5 seconds to lower it.
  • Repeat this exercise 10 to 20 times. Change sides. Do a total of 3 sets on each side.
Illustration: Leg extensions while sitting

This exercise strengthens the muscle at the front of the thigh.

Wall sits to strengthen the thigh muscles

  • Stand with your back flat against a wall.
  • Place your feet about 60 centimeters away from the wall. Your feet should be shoulder-width apart and flat on the floor, facing forward.
  • Now fold your arms in front of you and slowly slide your upper body down the wall until your thighs and lower legs are at a 90-degree angle.
  • You’ve arrived in the correct position when your thighs are horizontal, your kneecaps are facing forward, and your back is pressed flat against the wall.
  • Hold this position for about 20 to 30 seconds at first. After some time you can gradually increase to one minute by adding 5 to 10 seconds each time.
  • Repeat the exercise 3 times. After each wall sit, slide your upper body back up the wall by straightening your legs and have a 30-second break.
Illustration: Wall sits

This exercise strengthens the muscles at the front of your thighs.

Squats

  • Stand straight with your legs about shoulder-width apart and your toes pointed slightly outward.
  • Still standing, gradually bend your knees and straighten them again.
  • When you bend your knees, your hips move back (as if you’re going to sit down on a chair). Your body’s center of gravity should stay above the knee joints.
  • Your neck and head should be lined up with your back, which you keep straight (don’t let it curve forward).
  • To keep your balance, you can stretch your arms out in front of you.
  • Start by doing quarter squats at first – in other words, bending your legs at about 45 degrees.
  • If that isn't painful, increase to half squats until your thighs are almost horizontal (parallel to the floor). You can use weights after some time to increase the intensity.
  • Do a total of 3 sets of 10 to 20 repetitions, with a break of 30 to 60 seconds between them.
Illustration: Squats

This exercise strengthens the muscles at the front of the thighs.

Step-ups

  • You will need a stable bench or an aerobic step for this exercise.
  • Stand about 10 cm in front of the step or bench.
  • Put your right foot on it and then step up onto it by straightening your right leg.
  • Lift your left leg until your thigh is horizontal (parallel to the ground).
  • Put your left leg back down on the ground again.
  • To help keep your balance, move your arms in the opposite direction to your legs.
  • Repeat 10 to 20 times and then change sides. Do 3 sets in total.
  • Because step-ups put a lot of strain on the knees, you shouldn’t do them if they hurt too much. The higher the step or bench, the more difficult step-ups are. If you can’t keep your legs stable, you should use a lower step or bench.
Illustration: Step-ups

This exercise strengthens the muscles at the front of the thighs and the muscles in your bottom (gluteal muscles).

What should I pay attention to while doing the exercises?

It is important to do the exercises properly and safely. In other words:

  • avoid sudden movements,
  • make sure you keep a good posture – your core should be stable and your legs should be straight: don’t bend your knees inward or outward,
  • wear comfortable sports clothes that allow you to move freely, and
  • sturdy, cushioned athletic shoes with non-slip soles.

It is also important to make sure that the exercises don’t hurt too much. You can use a scale of 1 to 10 while doing the exercises (1 = no pain, 10 = very bad pain): If pain occurs, it shouldn’t be worse than 3 out of 10 on the scale. If it is worse, you can do fewer repetitions or reduce the intensity of the exercises, for instance.

It is best to consult your physical therapist or doctor if you have any questions. It is also a good idea to get professional advice if you have other medical conditions or health problems. Together you can find an exercise program that is suitable for you.

If your knee joint is inflamed, swollen and hurts even at rest, you shouldn’t do any strengthening exercises.

Collins NJ, Barton CJ, van Middelkoop M et al. 2018 Consensus statement on exercise therapy and physical interventions (orthoses, taping and manual therapy) to treat patellofemoral pain: recommendations from the 5th International Patellofemoral Pain Research Retreat, Gold Coast, Australia, 2017. Br J Sports Med 2018; 52(18): 1170-1178.

Esculier JF, Bouyer LJ, Dubois B et al. Is combining gait retraining or an exercise programme with education better than education alone in treating runners with patellofemoral pain? A randomised clinical trial. Br J Sports Med 2018; 52(10): 659-666.

Nascimento LR, Teixeira-Salmela LF, Souza RB, Resende RA. Hip and Knee Strengthening Is More Effective Than Knee Strengthening Alone for Reducing Pain and Improving Activity in Individuals With Patellofemoral Pain: A Systematic Review With Meta-analysis. J Orthop Sports Phys Ther 2018; 48(1): 19-31.

Rogan S, Haehni M, Luijckx E et al. Effects of Hip Abductor Muscles Exercises on Pain and Function in Patients With Patellofemoral Pain: A Systematic Review and Meta-Analysis. J Strength Cond Res 2019; 33(11): 3174-3187.

Van der Heijden RA, Lankhorst NE, van Linschoten R et al. Exercise for treating patellofemoral pain syndrome. Cochrane Database Syst Rev 2015; (1): CD010387.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Seven exercises to stabilize the knee

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Updated on January 30, 2024

Next planned update: 2027

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Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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