Working Out With a Knee Injury: 6 Low-Impact Ab and Butt Exercises

Getting a quality ab and butt workout after an injury to your knee isn’t an impossible task. Many low-impact exercises target these muscles while placing little to no strain on the knee joint.

Even with a knee injury or joint pain in your knees, it’s important to stay active, according to the Mayo Clinic. Keeping your muscles strong and flexible is the best way to prevent additional future injuries, according to OrthoInfo.

Using a few simple modifications, these knee-friendly exercises can strengthen your butt and abdominal muscles even as you recover or manage your pain. Aim to complete two to four sets of 8 to 12 repetitions of each exercise. You can do this routine two to three times per week.

Before you jump into this routine, though, make sure you’ve spoken with a doctor about your situation and that they’ve cleared you for these exercises.

It’s okay if you can’t return to your usual activity levels right away — take it slow and focus on gradual progress, NHS Inform says. And if you experience any pain while exercising, stop the activity and contact your doctor to avoid making your knee issues worse.

1. Posterior Pelvic Tilt

The posterior pelvic tilt exercise works out your abs and glutes:

1. Lie on your back, with your knees bent and your feet flat on the floor. If your injured knee is unable to bend to this angle, straighten the affected leg slightly to find a more comfortable position.
2. Draw your pelvis in toward your bellow button and flatten your spine against the floor. Maintain this position for 5 to 10 seconds, breathing normally.
3. Relax your muscles, then repeat for the indicated number of repetitions.

2. Pike Plank

Pike planks are a full-body movement that works your abs, quads, shoulders, and chest. If you find this exercise too difficult, you can do a standard plank instead.

Here’s how to do a pike plank:

1. Start in plank position, with your hands on the floor beneath your shoulders and your feet hip-width apart.
2. Keeping your elbows and knees straight, drive your hips back so that your body forms an upside down V position. (This is similar to Downward Dog, except your heels don't need to be flat on the floor.)
3. Hold for 5 to 10 seconds, then return to the starting position. Repeat for the desired number of repetitions.

3. Prone Hip Extension

Hip extensions are a great way to activate the gluteus maximus muscle without subjecting your injured leg to undue stress:

1. Lie on your stomach. Though this exercise is typically done with a bent knee, modify it to keep your legs straight to avoid aggravating your injured or painful knee. Place a pillow under your painful leg if this position is uncomfortable.
2. Without bending your knee, lift your right leg in the air as high as you can. Do not allow your right hip to lose contact with the floor.
3. Keep your leg in the air for 5 to 10 seconds before lowering it back down.
4. After performing one set with the right leg, repeat the exercise on the left side.

4. Front Plank

Front planks, sometimes also called low planks, provide a great abdominal workout without requiring you to bend or put pressure on your knees. (If you do need to modify this exercise by performing it on your knees, you can put a pillow or cushion under them.)

Here’s how to do a front plank:

1. Brace yourself on your forearms, with your elbows under your shoulders and your feet hip-width apart. Make sure your spine forms a straight line.
2. Engage your abs and avoid letting your back arch. Hold this position for 10 seconds.

5. Swiss Ball Bridge

Bridging with a ball adds instability to an already challenging butt exercise, meaning it also works your core:

1. Lie on your back with your arms by your side and your legs straight out in front of you and elevated so that your knees, calves, and feet rest on a stable surface, like a couch, or (after you’ve become accustomed to the exercise) a less unstable surface like an exercise ball to give more of a workout to your core.
2. Keeping your knees completely straight, squeeze your core and lift your butt in the air. (You can add to the challenge by crossing your arms over your chest as you bridge.)
3. After 5 to 10 seconds, return to the starting position.

6. Side Plank

Side planks activate your abs, butt, and hips. This exercise targets the muscles on the sides of your torso to build lateral core strength:

1. Lie on your right side, with your legs straight out and stacked on top of each other. Bend your right elbow at a 90-degree angle directly beneath your shoulder.
2. Lift your bottom hip in the air, keeping your spine straight. Hold for 10 seconds before lowering back down.
3. After performing one set on your right side, flip over and repeat the exercise on your left side.