Short arc quads strengthen the front of the thigh (quadriceps) through the last part of straightening the knee. You rest your knees over a roller and lift one heel until the leg is straight. It is commonly used early in knee rehab and after knee surgery.

How to do the short arc quads

Lean back on your forearms on a bed, as in the video, with both legs out in front. If that strains your back or shoulders, lie flat with a pillow under your head.
Place a foam roller across the bed under both knees. A firm rolled towel or blanket works if you do not have one. Let your legs rest comfortably over it, knees slightly bent and heels on the bed.
On your affected leg, tighten the front of your thigh and lift your heel off the bed until the knee is fully straight. The back of the knee stays resting on the roller.
Hold the straight position for 3 to 5 seconds. Keep breathing.
Lower the heel slowly back to the bed and relax.
If your program includes both legs, repeat with the other leg.

What you should feel

Work in the front of the thigh, strongest when the knee is fully straight.

Common mistakes

Lifting the back of the knee off the roller, which turns it into a leg raise.
Stopping short of fully straight. That last bit is the point of the exercise.
Letting the heel drop instead of lowering it.
Holding your breath during the hold.

How often

Many programs use 2 to 3 sets of 10 to 15 with a 3 to 5 second hold at the top, once or twice a day. After surgery, the plan from your surgeon and physio comes first, and your physio will adjust the numbers as you go.

Stop and check with your physio if

Knee pain increases sharply during the set.
Your calf or thigh is getting more swollen, or becomes warm, tender, red or darker than usual, or has a new throbbing or cramping pain. This can be a blood clot, especially after an operation, an injury, time in a cast, boot or brace, or a spell of being much less mobile than usual, and after an operation it can also be an infection. Stop and contact your medical team or get medical advice the same day. If you are also short of breath or have chest pain, call emergency services.
Your wound becomes more red, hot, swollen or painful, or starts to leak. Contact your medical team the same day.

From the clinic

The size of the roller changes the exercise. A bigger roller starts the knee more bent and asks more of the thigh, while a small towel roll keeps the movement short. If the knee will not go fully straight yet, lift as far as you can and hold there.

Physios often use it as a step between quad sets and straight leg raises, for a knee that still bends when you try to lift the whole leg.

Reviewed by the PocketPhysio by VirtueLife expert physiotherapy team. Last reviewed 2026-09-25.

This page is general education, not a diagnosis or a personal treatment plan. If you have pain, an injury or a health condition, see a physiotherapist or doctor before starting new exercises.

Short arc quads