Exercise after a total knee replacement can increase mobility and strengthen the muscles around the knee joint. Walking, stair climbing, and activities that target specific muscles may all help.
Once people regain independence by walking short distances postsurgery, they may start more advanced exercises. These could include cycling with a stationary bike or performing resistance exercises.
However, people with a knee replacement should avoid high impact activities that put stress on the joint, such as jogging or jumping.
This article discusses the best exercises after a total knee replacement, the ones to avoid, and how soon a person can start.
Several exercise types can be beneficial after a knee replacement. These include:
- stair climbing
- resistance training
After recovering from knee replacement surgery, a doctor or physical therapist may recommend 20–30 minutes of exercise a day. They may also combine this with a recommendation to walk for 30 minutes 2–3 times a day.
Knee replacements consist of plastic and metal, so activities that put too much stress on them may reduce their longevity. High impact activities may loosen the band attaching them to the bone, resulting in earlier wear of the plastic.
High impact exercises and sports include:
- jump rope
- jumping jacks
- running or jogging
People can start doing specific postoperative exercises as soon as they feel able. This could be from their bed or while they are still in the hospital.
Beginning postoperative exercises can also increase knee movement and strengthen muscles. The exercises may initially feel uncomfortable but may help decrease postoperative pain and hasten recovery.
Learn more about recovery after a total knee replacement.
Below are some postoperative exercises the American Academy of Orthopedic Surgeons (AAOS) suggests after knee replacement surgery.
To perform this exercise:
- Lie on the back and tighten the muscles in one thigh.
- Try to straighten the knee. Hold for 5–10 seconds.
- Do this 10 times within a 2-minute period. Rest for 1 minute and then repeat.
Keep repeating until the thigh feels tired, then switch to the other leg.
To do this exercise:
- Lying on the back, move the foot up and down while keeping the leg out straight.
- Do this for 2–3 minutes, 2–3 times an hour.
- If watching TV, repeat during each commercial break.
A person should do this until they have fully recovered and the swelling in the lower leg and ankle has disappeared.
Bed-supported knee bends
To do this exercise:
- While lying down, bend one knee and slide the foot toward the buttocks, keeping the heel on the bed.
- Slowly bend the knee as far as possible, then hold the knee in that position for 5–10 seconds.
- Slide the foot back down, straightening the leg.
- Repeat until the leg feels tired.
Straight leg raises
To perform this movement:
- Lie back and straighten the leg. Tighten the thigh muscles.
- Lift the leg several inches off the bed and hold for 5–10 seconds.
- Slowly lower the leg.
- Repeat until the thigh feels tired.
- This exercise should take 3 minutes.
These are exercises a person can do once they can sit or stand.
Sitting-supported knee bends
To do this exercise:
- Sit on the bedside or in a chair, ensuring the thighs have support.
- Cross the ankles, putting the foot of the unoperated leg behind the other, with the legs out straight.
- Slowly bend the knee as much as possible. Hold this position for 5–10 seconds.
- Repeat several times until the leg feels tired.
Beginning to walk again is an important part of recovery. At first, a person will need to use a walker. To do this:
- Stand up straight, holding the bars of the walker.
- Advance the walker a short distance, reach forward with your operated leg knee straightened so the heel of the foot touches the floor first.
- Move forward so the knee and ankle bend and the entire foot rests evenly on the floor.
- As this step completes, the toe will lift off the floor. The knee and hip will also bend to reach forward for the next step.
- Advance like this for a short distance.
After walking, a person may lie down, elevate the knee, and ice it to reduce swelling.
Going up and down stairs
Stair climbing can also strengthen the knees. To start stair climbing:
- Choose a flight of stairs that are not too steep and have a hand rail for support. Place a hand on the rail.
- When going upstairs, lead with the unoperated knee. When going downstairs, lead with the operated knee.
- Take each step on the stairs one at a time. Ascend with one leg, then bring the other up to the same level.
- If possible, have someone to offer support when necessary. This may help until a person has regained most of their strength.
- Once people regain mobility and strength, they may climb stairs foot over foot.
After someone can walk independently for short distances or easily climb a few steps, they can start more advanced activities. These involve specific exercises for strength and mobility.
Standing knee bends
To do this exercise:
- Stand up using crutches or a walker. Lift the thigh and bend the knee as much as possible.
- Hold the position for 5–10 seconds.
- Straighten out the knee, touching the floor with the heel first.
- Repeat several times until tired.
- This exercise should take 2 minutes.
People can also do this exercise with light weights to add resistance. Doctors may suggest beginning resistance exercises 4–6 weeks after surgery. Gradually increase the weight as strength improves.
Cycling on a stationary bike
To do this movement, a person will need access to a stationary upright exercise bike. To use one:
- Adjust the seat height so that the bottom of the foot just touches the pedal.
- Pedal backward. After becoming comfortable with this, pedal forward.
- Pedal 10–15 minutes twice a day, and gradually work up to 20–30 minutes, 3–4 times a week.
- As strength increases around 4–6 weeks, slowly raise the bike tension.
A person should perform the exercises a physical therapist recommends for at least 2 months following surgery.
Exercises after a total knee replacement include those that target muscle groups supporting the knee joint. Walking and stair climbing are also beneficial.
People can begin certain postoperative exercises from their bed, slowly building up to more advanced movements as they recover. Once people can walk a short distance independently, they can add more advanced activities, such as cycling and resistance exercises.
A knee replacement will last longer if a person avoids high impact activities, such as jogging and jumping.