Knee strengthening exercises do not affect the knee joint directly, but they strengthen the muscles surrounding it. Strong muscles in the legs can help provide support for the knees. This support may alleviate pressure and strain on these joints, which can relieve pain and help a person be more active.
Always warm up with light exercise before starting any knee strengthening exercises. Examples of gentle exercise include walking, and cycling, all of which put minimal stress on the knees. This activity will help increase blood flow to the muscles and allow them to be more flexible.
Exercises for the Knee
The following exercises can help strengthen the muscles surrounding the knee.
Leg lifts
Muscles involved: Quadriceps (front of the thigh) and abdominal (stomach) muscles.
- Lie down on the floor with the back flat. Use a yoga mat, folded blanket, or exercise mat for comfort on a hard floor.
- Keep the left leg straight and bend the right leg slightly at the knee, bringing the foot closer to the body.
- Pull the abdominal muscles inward by imagining the belly button pulling down toward the floor. Doing this should bring the lower back down against the floor and help provide extra support during the exercise. Place a hand beneath the lower back to make sure that there is no space between the small of the back and the floor. If there is space for the hand, gently push the lower back down on top of the hand.
- Slowly lift the left leg without bending the knee. Keep the toes pointed toward the ceiling and stop when the leg is about 12 inches off the floor. It should not be higher than the bent knee on the right leg.
- Hold the left leg up for 5 seconds.
- Slowly lower the leg back down to the floor. Do not put it down too quickly or let it drop.
- Repeat two more times with the same leg.
- Switch sides and repeat.
What not to do
- Do not let the back arch during the exercise.
- Do not jerk or bounce the leg or lift it above the knee on the bent leg.
- People who have osteoporosis or a back compression fracture should not perform this exercise.
Standing hamstring curl
Muscles involved: Hamstrings (back of the thigh) and gluteal (buttock) muscles.
- Stand straight with the knees only 1–2 inches apart. Hold on to a stable chair, the countertop, or another object for balance.
- Slowly bend one knee behind the body, lifting the heel off the floor while keeping the thighs aligned. Continue to lift the heel in a smooth motion until the knee bend reaches a 90-degree angle. Keep the straight leg slightly bent to avoid locking it.
- Hold the bent leg up for 5 seconds and then slowly lower it to the floor.
- Repeat two more times with the same leg.
- Switch sides and repeat.
What not to do
Do not point the toes or flex the foot on the lifted leg. Allow the foot to remain in a neutral, flat position.
Hamstring curls on a weight bench
Muscles involved: Hamstrings and gluteal muscles.
This exercise is a variation of the standing hamstring curl. A person can try this version if they have access to a weight bench that is purpose-built for this exercise. It may be more challenging than the standing hamstring curl, depending on how much weight a person uses.
- Lie face down on the bench with the knees close together. Grip the handles for stability.
- Tuck the feet under the weight. The weight should sit just above the heels.
- Slowly bend both knees, using the force of the legs to raise the weight up. Continue to lift the weight in a smooth motion until the knees bend at a 90-degree angle.
- Hold the weight up for 5 seconds and then slowly lower it back down.
- Perform up to 15 repetitions (reps).
What not to do
When first attempting this exercise, do not use a heavyweight. Beginners should use the lowest weight and work their way up to heavier weights as they build strength.
Step exercises
Muscles involved: Quadriceps, hamstrings, hip flexors, and gluteal muscles.
- Use a large, sturdy stool or exercise platform no taller than 6 inches.
- Step up onto the stool with the right foot and allow the left foot to follow behind. The left foot should not be on the stool but should hang behind it.
- Keep the bodyweight on the right foot and hold for up to 5 seconds.
- Slowly lower the left foot down and then follow it with the right foot.
- Switch legs, stepping up with the left foot first.
- Repeat.
What not to do:
- Do not lock the knees during this exercise. The knees should remain slightly bent.
- Do not allow any part of the stepping foot to hang off the stool or platform.
- People who have issues with balance should not perform this exercise.
Single-leg dip
Muscles involved: Quadriceps, hamstrings, and gluteal muscles.
- Use two high-backed, stable chairs, placing one on either side of the body with the chair backs next to the arms. Place a hand on the back of each chair for balance.
- Lift right leg about 12 inches from the ground. All weight should be on the left leg.
- Slowly bend down a few inches, pushing weight onto the heel of the supporting leg.
- Hold for 3–5 seconds.
- Slowly straighten up.
- Repeat and switch sides.
What not to do:
- Do not lean backward when lifting the leg. Keep the back and upper body straight.
- Do not allow the knee to move forward over the toes in the supporting leg.
Note: If you experience pain during these exercises, you should stop doing them and speak to a doctor. Anyone with severe knee pain should consult a doctor before trying to exercise.
