Frog on the Reformer: Steps, Muscles and Common Mistakes

How to do the Frog on the Reformer

Lie on your back on the Reformer carriage with your feet in the long straps, bringing your heels together and opening your knees to the sides.

1. Settle your pelvis into a neutral position on the carriage so your lower back is not flattened or overly arched.
2. Keep your heels glued together and point your toes slightly outward.
3. Press your feet into the straps to extend your legs out and down at a diagonal angle.
4. Straighten your legs completely while actively squeezing your inner thighs and glutes.
5. Hold this extended position for a brief moment to feel the back of your legs working.
6. Bend your knees to slowly control the carriage as it returns to the starting position.
7. Stop bending your knees when they are roughly over your hips, keeping your spine completely still throughout the movement.

• Breath. Teachers cue breathing differently, but you will often exhale as you press your legs out and inhale as you bend your knees to return. Some instructors prefer the reverse, so follow what feels most natural for your core control.
• Where you feel it. You should feel your inner thighs, glutes, and the back of your thighs working hard to move the straps. You should not feel any pinching in your lower back or strain in your neck.
• How many. 8 to 10 controlled repetitions

Common mistakes

• Tucking your pelvis. Keep your tailbone heavy on the carriage to maintain a neutral spine.
• Letting your heels separate. Press your heels firmly together the entire time to help activate your inner thighs.
• Pressing the legs too low. Only lower your legs as far as you can without your lower back arching off the carriage.
• Rushing the return. Resist the pull of the springs as you bend your knees back to the start.
• Bringing the knees too close to the chest. Stop the carriage return when your knees are directly above your hips to keep tension on the muscles.

Make it easier or harder

Easier

• Use a lighter spring setting to reduce the resistance on your legs.
• Press your legs out at a higher angle toward the ceiling, which makes it easier to keep your spine neutral.
• Practice the leg movement on a mat without the Reformer straps to learn the coordination first.

Harder

• Add a heavier spring to increase the challenge for your gluteus maximus and hip adductors.
• Lower the angle of your leg press slightly, as long as you can hold your neutral spine steady.

Who should be careful

• After the first trimester of pregnancy, many guidelines advise against long periods lying flat on the back. A side-lying or propped version is an alternative.
• Reformer springs and the moving carriage add load and instability. Learn it with a qualified instructor, who can set the springs for your body and goals.

Related exercises

• Feet in Straps Beginner to intermediate
• Reformer Footwork Beginner
• Front Splits Advanced
• Pelvic Lift on the Reformer Beginner to intermediate
• Semi-Circle Advanced

When to see a doctor or physical therapist

• Sharp pain in your lower back or tailbone area.
• A clicking or popping sensation in your hips that causes discomfort.
• Numbness or tingling running down your legs.
• Pain in your knees when you bend or straighten them.

This page is general education, not a diagnosis or treatment plan. If you have a health condition, are pregnant or are recovering from an injury or surgery, check with your own clinician before trying new exercises.

How we put this page together. Exercise data (type, level, equipment and muscles) was compiled by our editors from the classical mat order in Joseph Pilates’ 1945 book and from commonly taught reformer repertoire. Muscle lists are a general anatomy guide; cueing differs between teachers. Text drafted with AI assistance and checked by the Editorial Team. See our editorial policy. Last checked October 2026.