# Lying Hip Knee Raise - Canonical: https://fitwill.app/exercise/8136/lying-hip-knee-raise/ - Media ID: 8136 - Primary muscle: Abs - Body part: Core - Equipment: Body Weight - Video: https://fitwill.app/videos/8136/lying-hip-knee-raise.mp4 ## Description The Lying Hip Knee Raise is a floor-based core movement where you start lying on your back with your legs extended and lifted clear of the floor, then pull your knees in toward your chest while curling your hips up off the ground. Unlike a basic knee tuck that only moves at the hip joint, the defining part of this exercise is the posterior pelvic tilt at the top, when your lower back peels away from the floor and your hips rise. That curl is what separates a genuine abdominal contraction from a movement dominated purely by the hip flexors. The main targets are the lower portion of the rectus abdominis along with the deep transverse abdominis, while the hip flexors work hard to bring the thighs toward the torso. Keeping the legs extended rather than bent throughout adds a long lever, which significantly increases the demand on both the abs and the hip flexors compared with a standard reverse crunch. Because it requires no equipment beyond floor space, it fits easily into home workouts, warm-ups, or the tail end of a training session. This exercise suits anyone with a reasonable base of core strength who wants to progress beyond crunches and leg raises. It is particularly useful for people who feel hanging leg raises in their forearms or grip before their abs, since the floor removes grip and shoulder fatigue from the equation entirely. Athletes in sports that involve sprinting, kicking, or changing direction also benefit, as those actions demand strong, controlled hip flexion under trunk stability. Setup quality determines whether this movement trains your abs or irritates your lower back. Lie flat with your arms relaxed at your sides, palms pressing lightly into the floor for balance, and only begin once your lower back is flattened against the ground. The common failure point is letting the lumbar spine arch as the legs extend, which shifts load onto the erector spinae and hip joints instead of the abdominals. If you cannot keep your back flat with straight legs, start with slightly bent knees or keep your heels closer to the floor and progress the lever length over time. To execute well, think of the repetition as two phases: first the knees travel toward the chest, then the hips curl upward so your pelvis rolls toward your ribs. Pause briefly at the top, then lower with control until your legs return to the extended, elevated starting position without touching the floor. Exhale as you curl up and inhale on the way down. Keep the tempo slow enough that your abs, not momentum, are doing the work, and stop the set when your lower back starts to lift or arch during the lowering phase. ## Instructions 1. Lie flat on your back on an exercise mat or the floor with your legs fully extended and your arms resting at your sides, palms facing down against the floor. 2. Press your lower back gently into the floor, brace your abdominals, then raise both straight legs together until your feet point at the ceiling or slightly beyond, keeping your back flat. 3. From this extended position, bend your knees slightly if needed and begin drawing them in toward your chest. 4. As your knees approach your torso, curl your hips up off the floor so your pelvis rolls toward your ribs rather than just folding at the hips. 5. Pause for a beat at the top with your hips lifted and your knees pulled close to your chest, feeling your lower abdominals shorten. 6. Lower slowly and in reverse order: uncurl the hips first so the spine returns to the floor, then extend the legs back out to the elevated starting position. 7. Stop the descent just before your heels touch the floor so tension stays on the abs and your lower back remains pressed down. 8. Exhale as you curl the hips up, and inhale as you lower the legs back out. 9. Complete your repetitions without letting the lower back arch between reps, resetting the brace each time the legs reach full extension. ## Tips & Tricks - If your lower back arches when the legs extend, shorten the lever by keeping a slight knee bend throughout, then gradually straighten the legs over several weeks. - Place your hands flat on the floor beside your hips and press down lightly during the curl; this gives you balance feedback without turning it into a pushing movement. - Do not let your heels rest on the floor between repetitions, as that releases abdominal tension and turns each rep into a fresh, momentum-assisted swing. - The curl of the hips is the part most people skip; if only your knees move and your pelvis never rolls up, you are doing a hip flexion drill rather than training the lower abs. - Slow the lowering phase to two or three seconds; the eccentric portion is where the extended-leg position becomes most demanding on the abdominals. - Avoid yanking your knees in with a fast bounce, which shifts the work to momentum and hip flexor snap instead of controlled abdominal shortening. - Keep your head and shoulders relaxed on the floor; craning the chin forward does nothing for the abs and often creates neck tension. - Stop the set when your hips no longer clear the floor at the top, since continuing past that point usually means the lower back starts absorbing the load. - A thicker mat helps if you find your tailbone or sacrum uncomfortable as the hips curl and press into the ground at the top of each rep. ## Frequently Asked Questions ### Which muscles does the Lying Hip Knee Raise work the most? The lower portion of the rectus abdominis and the deep transverse abdominis do the primary work, especially during the hip curl. The hip flexors, including the iliopsoas and rectus femoris, assist strongly as the knees travel toward the chest. ### Why do my hip flexors burn more than my abs during the Lying Hip Knee Raise? This usually means the movement is stopping at knee tuck stage without the pelvic curl. Focus on rolling the hips off the floor at the top of each rep, and slow the tempo so the abdominals, not momentum, drive the motion. ### Is the Lying Hip Knee Raise suitable for beginners? It is moderately demanding because the legs stay extended, which creates a long lever. Beginners should start with bent knees, or with the heels resting near the floor between reps, and progress to straight legs once the lower back stays flat throughout. ### How is the Lying Hip Knee Raise different from a reverse crunch? Both share the same pelvic curl at the top, but the Lying Hip Knee Raise begins with the legs extended and elevated rather than knees bent and feet on the floor. The longer lever makes it harder on the abs and hip flexors. ### Should my heels touch the floor between repetitions? No, lowering until the heels hover just above the floor keeps continuous tension on the abdominals. Letting the feet rest down gives the abs a break and invites the lower back to arch as you restart each rep. ### Can I do the Lying Hip Knee Raise if my lower back bothers me during leg raises? Try keeping a moderate knee bend for the entire set and reducing how far you lower the legs, stopping well before the back arches. If discomfort persists, stop the exercise and consult a qualified professional before continuing. ### What can I use instead of the Lying Hip Knee Raise at home? A reverse crunch with bent knees is the closest easier substitute, and a lying leg raise with straight legs is a harder variation that removes the hip curl. Hanging knee raises work the same pattern but add grip and shoulder demands. ### How many repetitions of the Lying Hip Knee Raise should I aim for? Most people do well with two to four sets of 8 to 15 controlled repetitions. Prioritize full hip curls over rep count; a set of quality reps where the hips clearly leave the floor beats a longer set where they never do. ### Why does my neck feel tense during this exercise? Neck tension usually comes from lifting or craning the head to watch your legs. Keep the back of your head resting on the floor, eyes toward the ceiling, and let your arms and trunk do all the moving.