# Lying Side Reverse Crunch - Canonical: https://fitwill.app/exercise/7376/lying-side-reverse-crunch/ - Media ID: 7376 - Primary muscle: Obliques - Body part: Core - Equipment: Body Weight - Video: https://fitwill.app/videos/7376/lying-side-reverse-crunch.mp4 ## Description The Lying Side Reverse Crunch is a floor-based core exercise that combines the hip-curling action of a reverse crunch with a diagonal twist toward one side. You lie flat on your back with your arms spread wide for support, raise your legs, bend the knees, and then curl your hips up and off the floor while steering your knees diagonally toward the same-side shoulder. That added rotation is what separates it from the standard reverse crunch and shifts a large share of the work onto the obliques. The main muscles at work are the obliques on the side you are crunching toward, assisted by the lower portion of the rectus abdominis as the pelvis rolls upward. Because the knees travel through a curved, diagonal path rather than straight up, the deep trunk stabilizers also stay busy keeping the ribcage and shoulders glued to the floor. The hip flexors contribute to holding the legs up, though the lifting itself should come from the abs, not from swinging the legs. This setup matters more than people expect. The arms out wide act like outriggers: they give you a base of support so the rotation happens at the spine and pelvis instead of turning into a full body roll. Keeping your upper back and shoulders planted while the hips curl is the entire point of the movement. If the shoulders lift or the body tips over to one side, you lose the targeted oblique tension and turn the exercise into an uncontrolled roll. The Lying Side Reverse Crunch suits anyone who has mastered basic reverse crunches and wants more oblique involvement without equipment. It fits well at the end of a core session, in home workouts where no gear is available, or in programs aimed at rotational control for sports like tennis, golf, or martial arts. Because it is performed slowly and with a short range, it is also easier on the lower back than many loaded twisting exercises. To execute it well, think of the movement as rolling your hips up rather than pushing your legs somewhere. The knees travel diagonally over the chest toward the shoulder, the lower back peels off the mat, and the return is a slow, controlled unrolling that never lets the feet or hips crash down. Breathe out as you curl up, breathe in on the way down, and complete all repetitions on one side before switching, or alternate sides rep by rep if you prefer. Keep the expectations realistic. This is a bodyweight control exercise, so progress comes from slower tempo, a fuller pelvic curl, and cleaner diagonal paths rather than adding load. Stop short of any range where your lower back arches sharply or your shoulders start to lift, and treat smooth, quiet reps as the standard for a good set. ## Instructions 1. Lie flat on your back on an exercise mat with your legs extended and together, and spread your arms straight out to the sides at roughly shoulder height with palms facing down. 2. Lift both legs off the floor and bend your knees until they sit directly over your hips, shins parallel to the floor, feet relaxed. 3. Lightly press your arms and upper back into the mat to lock your shoulders in place, then brace your abs before the first rep. 4. Exhale and curl your hips upward off the mat, guiding your knees diagonally up and over your chest toward the shoulder on the same side as your feet. 5. Pause briefly at the top, when your lower back has lifted and your knees are as far over the chest as you can take them without your shoulders leaving the floor. 6. Inhale and lower your hips back down along the same diagonal path with slow control, stopping just before your lower back touches down so tension stays on the abs. 7. Complete all repetitions on one side, then rebracket your setup, rebrace, and repeat on the other side, or alternate sides rep by rep. 8. Keep your head neutral on the mat throughout and avoid pushing off with your hands; they are there for balance only. 9. Between sets, lower the legs fully, let the lower back settle onto the mat, and reset your arm position before the next set. ## Tips & Tricks - If your body rolls onto the outer edge of the working side, widen your arm position slightly and press the opposite palm harder into the mat. - The most common mistake is letting the legs do the work: if your knees simply swing side to side while the hips stay glued to the floor, the obliques are barely working. Focus on lifting the pelvis, not moving the knees. - Bend the knees to about 90 degrees; straightening them lengthens the lever arm and tends to turn the rep into a hip flexor and leg-swing exercise. - Keep the diagonal path honest. Knees should travel toward the same-side shoulder, not straight up and not all the way sideways across the body. - Do not yank your head or press your hands down to launch the movement; if you feel yourself doing that, the set is too long or the tempo is too fast. - If your lower back arches between reps, shorten the lowering range and stop just before the pelvis settles fully onto the mat. - A slow two-second up and three-second down tempo makes this exercise noticeably harder without any equipment, so use tempo before you look for harder variations. - Exhale fully as you curl up; letting the breath go helps the ribs drop and the abs shorten instead of bracing high in the chest. ## Frequently Asked Questions ### Which muscles does the Lying Side Reverse Crunch target most? The obliques on the side you crunch toward do most of the work, with the lower abs and deep core stabilizers assisting as the pelvis curls. The hip flexors help hold the legs up but should not drive the movement. ### How is the Lying Side Reverse Crunch different from a regular Reverse Crunch? The regular version sends the knees straight up over the hips, while this variation steers them diagonally toward the shoulder, which adds rotation and shifts emphasis onto the obliques. ### Is the Lying Side Reverse Crunch suitable for beginners? Yes, as long as you keep the range short and the tempo slow. If a full pelvic curl is too difficult, start with small lifts of the hips and build up gradually. ### Why do my arms need to be out to the sides during the Lying Side Reverse Crunch? The wide arm position acts as a brace so your shoulders and upper back stay planted while the hips rotate. Without it, the whole body tends to tip and the obliques stop doing the work. ### Should my shoulders stay on the floor the whole time? Yes. The moment your shoulders peel off the mat, the rotation has turned into a body roll rather than a spinal curl, and tension leaves the target muscles. Reduce the range if that keeps happening. ### Can I do the Lying Side Reverse Crunch without a mat? You can do it on carpet or another padded surface, but a mat is recommended because your lower back and spine press into the floor throughout the set. ### What can I substitute if the twisting motion bothers my lower back? Use a standard reverse crunch with the knees traveling straight up over the hips, which trains the lower abs with no rotation. Only return to the side variation once the straight version feels comfortable. ### How many repetitions of the Lying Side Reverse Crunch should I do? Eight to twelve controlled reps per side works well, focusing on a full pelvic curl and a slow return. Add sets or slow the tempo before adding any external load. ### Why do my hip flexors feel this exercise more than my abs? That usually means the knees are swinging instead of the hips curling. Bend the knees more, slow the tempo, and concentrate on lifting the pelvis off the mat rather than moving the legs.