Straight Leg Raise
Talk to your doctor first. General education, not medical advice.This content is general education, not medical advice, diagnosis or treatment. Get approval from your physician or another qualified healthcare provider before starting any exercise program, especially if you have a medical condition, a recent injury or surgery, are pregnant, or take medication. Stop and seek medical advice if an exercise causes pain, dizziness, chest discomfort or shortness of breath. You choose to exercise at your own risk. Read the full medical disclaimer.
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Why it helps
The quadriceps protect and support the knee. They weaken quickly after injury, surgery or a period of knee pain. The straight leg raise works them with the knee kept straight, so there is little load through the joint.
It is a staple of early knee rehab and knee osteoarthritis programs, often paired with quad sets and short arc quads. See our knee osteoarthritis guide for a full routine.
Step-by-Step Instructions
- Lie on your back on a firm bed or mat. Bend one knee with the foot flat; keep the other leg straight.
- Tighten the thigh muscle of the straight leg so the back of the knee presses down and the kneecap draws up.
- Keeping the knee locked straight, lift the leg until it is level with the bent knee (about 30 cm).
- Hold for 1 to 2 seconds at the top.
- Lower the leg slowly and with control. Relax briefly, then repeat. Switch legs if both are to be worked.
What you’ll need Paid links
What this exercise uses, with household swaps where they work.
- Exercise mat · Non-slip, about 6 mm (1/4 in) thick, for floor exercises. A rug or folded blanket works.
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Key Form Cues
- Lock the knee: Tighten the thigh before you lift and keep it tight the whole time.
- Bent knee helps: The bent knee protects your lower back.
- Slow down: Take 2 to 3 seconds to lower.
How much to do
2 to 3 sets of 10 slow reps on each leg, once a day. After surgery, follow the dose your surgical team gives you.
Progression & Regression
Regression (Make It Easier)
- Do quad sets first until you can hold the knee straight
- Lift only a few centimeters
- Do fewer reps with longer rests
Progression (Make It Harder)
- Add a light ankle weight (start with 0.5 to 1 kg)
- Hold the top for 5 seconds
- Move on to standing exercises such as step-ups
Who it suits, and who should check first
Good fit for: knee rehab, knee osteoarthritis, quad weakness, and early recovery after knee surgery when your surgical team has cleared it.
Check with your clinician first if: you have had knee, hip or back surgery recently, cannot keep the knee straight as you lift, or have a new knee injury.
Precautions
Keep the knee straight and the back supported.
- After knee surgery, follow your surgical team’s protocol on when and how to start.
- If the knee bends as you lift (a “lag”), go back to quad sets and build up.
- Keep the other knee bent to protect your lower back.
- Stop and consult your provider if: you feel sharp knee or groin pain, new swelling or warmth in the knee, calf pain or swelling, or low back pain that spreads down the leg.
Frequently asked questions
Is the straight leg raise good after knee replacement?
It is commonly part of early knee replacement rehab. Your surgical team will tell you when to start and how many to do; see exercises after knee replacement.
Why does my knee bend when I lift my leg?
This is called a quad lag and usually means the quadriceps are weak. Practice tightening the thigh with quad sets until you can keep the knee straight.
How high should I lift my leg?
About level with the other bent knee, roughly 30 cm. Lifting higher works the hip more, not the thigh.
Video: Baptist Health on YouTube. We link to it because it shows the movement clearly; the written instructions and dosing on this page are our own general guidance.
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