Reverse Frog Crunch

Reverse Frog Crunch Exercise Description

The Reverse Frog Crunch is a bodyweight core exercise performed supine with the legs in a frog position (knees opened wide, soles of the feet together). The purpose is controlled posterior pelvic tilt and gentle lumbar flexion to curl the tailbone slightly off the floor, emphasizing the rectus abdominis with assistance from the obliques. Keeping the upper back anchored limits momentum and focuses the movement on the pelvis rather than swinging the legs. The frog-leg setup shortens the leg lever, which can make it easier to concentrate on curling the pelvis via the abdominal wall. Begin with hips and knees flexed around 90 degrees; the thighs remain quiet while the abdomen draws the pelvis toward the rib cage. Because the motion occurs primarily at the pelvis and lower spine, the hip joints move minimally, and the neck and shoulders stay relaxed on the floor. Expect a small, precise range of motion with steady breathing and consistent trunk tension.

Muscle Groups: Abs, Core, Waist
Target Muscles: Rectus Abdominis
Assisting Muscles: External Obliques, Internal Obliques
Stabilizing Muscles: Transversus Abdominis
Body Area: Upper Body
Body Parts: Core, Torso
Body Surface: Front
Body Symmetry: Other
Equipment: Bodyweight
Exercise Patterns: Other
Exercise Type: Strength
Functional Grouping: Trunk Flexors
Joint Involvement: Single-joint
Muscle Location: Stomach
Movement Direction: Other
Muscle Position: Anterior
Gender: Female

How To Do The Reverse Frog Crunch Exercise

‘- Lie on your back; arms by your sides, palms down for light support.
– Bring hips and knees to roughly 90 degrees; open the knees wide and press the soles of your feet together (frog position).
– Keep shins roughly parallel to the floor; relax the feet and keep the knees opened throughout.
– Set your ribcage down and brace lightly; maintain a neutral neck with gaze up.
– Exhale and posteriorly tilt the pelvis, flattening the low back gently into the floor.
– Initiate by curling the tailbone toward the ribs; lift the sacrum a few centimeters while the upper back and head stay down.
– Keep the thighs still; avoid kicking, swinging, or changing knee width.
– Pause briefly at the top with controlled tension.
– Inhale and lower slowly, placing the spine back down segment by segment to the start position without arching the low back.
– Reset your ribs and brace lightly before the next repetition.

Reverse Frog Crunch Tips

‘- Keep your upper back and head anchored to the floor so the movement comes from the pelvis, not from swinging.
– Maintain the frog position by keeping knees opened wide and soles of the feet pressed together throughout each rep.
– Keep your shins roughly parallel to the floor and feet relaxed to avoid turning this into a leg-swing.
– Lightly brace your trunk and set your ribcage down before you start and before each repetition.
– Exhale as you posteriorly tilt the pelvis, gently flattening your low back into the floor.
– Initiate the lift by curling your tailbone toward your ribs, raising the sacrum only a few centimeters.
– Keep your thighs still and avoid kicking, swinging, or changing the width between your knees.
– Use a small, precise range of motion and avoid arching your low back as you return to the start.
– Inhale as you lower slowly, placing the spine back down segment by segment with steady trunk tension.

Reverse Frog Crunch Beginner Introduction

Reverse Frog Crunch places the spotlight on the lower portion of the abs and side abs using only bodyweight on the floor. The movement happens while lying on the back with the legs in a relaxed, butterfly-style shape, which shortens the leg lever and shifts attention toward curling the pelvis. With about a right angle at the hips and knees, the thighs stay relatively quiet while the abdomen guides a gentle roll of the tailbone away from the mat. The upper body remains grounded, so momentum from swinging legs plays a minimal role.

This exercise highlights slow, deliberate control through the pelvis and lower spine rather than a big dramatic lift. The motion is small yet precise, emphasizing tension through the mid‑section as the pelvis glides toward the rib cage and then returns to the starting position. Breathing stays steady, with the effort phase matching a strong exhale and the lowering phase paired with a calm inhale, reinforcing a stable trunk and smooth rhythm throughout each repetition.