# Razor Curl - Canonical: https://fitwill.app/exercise/10961/razor-curl/ - Media ID: 10961 - Primary muscle: Hamstrings - Body part: Thighs - Equipment: Exercise Mat - Video: https://fitwill.app/videos/10961/razor-curl.mp4 ## Description The Razor Curl is a partner-assisted, kneeling body-weight exercise that trains the hamstrings and glutes through a long, controlled forward pivot. You kneel on a mat with a partner anchoring your ankles, then lower your entire body forward from the knees toward the floor and pull yourself back upright using the back of your thighs and hips. Because the movement happens with the knees bent and the torso pivoting ahead of them, the hamstrings work in a stretched position that most leg exercises never touch. This exercise suits lifters who already have some posterior-chain strength and want to build hamstring resilience without loading a barbell. Sprinters, martial artists, and field-sport athletes get particular value from it, since the razor curl mimics the hip-dominant, knee-bent positions those sports demand. It also works well as a supervised accessory movement for anyone progressing toward harder knee-flexion drills like Nordic curls. The setup matters more here than in most floor exercises. Your knees sit on a padded mat, your shins and feet stay behind you, and your partner pins your ankles firmly to the ground with both hands. A loose anchor is the number one reason people fail this drill: if your feet lift or slide, you lose the fixed pivot point and the hamstrings stop doing the work. Your arms stay crossed over your chest so they do not brace the fall, and your body forms one straight line from head to knees before you begin. From there, execution is a slow, hinged descent. Lean forward from the knees, letting your hips travel ahead of your torso as your chest lowers toward the floor. Keep your glutes and abs braced so your lower back does not sag, and go only as deep as you can control. To return, drive your hips forward and pull your torso back upright, feeling the hamstrings and glutes shorten to lift you. The descent should take two to three seconds; the ascent can be slightly faster but must never be a collapse or a jerk. In practice, the razor curl fits best at the end of a lower-body session or as a dedicated hamstring day finisher, typically for three to five sets of five to eight controlled reps. Stop each set when your form breaks, not when the burning starts, because a sloppy rep near the floor puts stress on the lower back and kneecaps. If you cannot yet control the descent, limit your range with a target such as a low bench or cushion placed under your chest and reduce it gradually over the weeks. ## Instructions 1. Kneel on an exercise mat with your knees hip-width apart and your body upright, shins flat behind you and toes pointing back. 2. Have your partner kneel behind you and clamp both hands firmly over your ankles, pressing them down into the mat so they cannot lift or slide. 3. Cross your arms over your chest and squeeze your glutes and abs so your body forms one straight line from head to knees. 4. Exhale and begin leaning forward from the knees, letting your hips travel ahead of your chest as your whole body pivots toward the floor. 5. Keep your thighs, hips, and torso locked together in a straight line the entire way down; do not bend at the hips or let your lower back arch. 6. Lower under control for two to three seconds until your chest nears the floor, or stop earlier if you feel your form slipping. 7. Pull back up by driving your hips forward and using your hamstrings and glutes to swing your torso back over your knees until you are upright again. 8. Breathe out on the way down and in as you pull back up, keeping each rep smooth rather than explosive. 9. Pause briefly at the top, reset your brace, and confirm your partner still has a firm grip before starting the next rep. ## Tips & Tricks - If your feet pop off the floor mid-rep, your partner needs to grip higher on the ankle bone and press down harder; an unanchored ankle turns the drill into a fall instead of a curl. - The most common mistake is breaking at the hips and folding your chest down first, which shifts work to the lower back. Cue yourself to move hips and head at the same speed, like a see-saw pivoting on the knees. - Place a folded towel or low pad under your chest as a depth target, and lower the target over time as your hamstrings get stronger. - Keep your arms crossed over your chest rather than reaching for the floor. Catching yourself with your hands removes tension from the hamstrings and can jar your shoulders. - Round the descent off before your chest slams down. Touching the floor with your face or chest at speed is the main safety risk in this movement. - If your kneecaps ache, double up the mat or kneel on a thicker pad. The knees carry your whole pivot here, so padding is not optional. - Do not turn the return into a lower-back snap. If you have to heave your trunk up with a big lumbar arch, cut the range or move to an easier regression. - Perform this early in a hamstring session while fresh if strength is the goal, or late as a finisher with shorter sets if endurance is the goal. - Spread your training days out; this drill leaves the hamstrings sore in a way curls usually do not, so avoid programming it the day before heavy sprints or deadlifts. ## Frequently Asked Questions ### What muscles does the Razor Curl work? The Razor Curl primarily targets the hamstrings, which control the forward pivot and pull you back up. The glutes, lower back, and abs work hard to keep your body in one straight line throughout. ### How is the Razor Curl different from a Nordic curl? Both are kneeling partner-assisted hamstring drills, but in a Nordic curl the body stays straight as it tips forward from the ankles, while in the Razor Curl the pivot happens at the knees with the hips driving ahead of the torso. The Razor Curl is usually the easier of the two and a good step toward the Nordic. ### Can beginners do the Razor Curl? Yes, but most beginners should limit the range of motion by lowering only partway toward the floor, or by placing a cushion under the chest to catch the depth. Full reps from the floor require significant hamstring strength. ### Why does my partner need to hold my ankles so tightly? Your partner's grip creates the fixed pivot point that lets your hamstrings work; if your ankles lift or slide, you either fall forward or lose the resistance entirely. A firm two-handed press over the ankles is essential for every rep. ### What should I do if I have no training partner? You can wedge your feet under a loaded barbell in a rack, a sturdy bench, or a lap-desk style anchor point so your ankles stay pinned. Some people also loop a band around fixed uprights and their shoulders to control the descent without assistance. ### How deep should I lower in the Razor Curl? Lower only as far as you can return from without your hips sagging or your chest dropping fast. For most people that starts out well above the floor and deepens over several weeks of practice. ### Why do my kneecaps hurt during this exercise? Your entire body pivots on your knees, so thin padding or a hard surface concentrates a lot of pressure there. Use a thick exercise mat or an extra folded towel under the knees and check that your weight rests on the soft tissue just above the kneecap rather than the bone itself. ### How many sets and reps should I use for the Razor Curl? Three to five sets of five to eight slow, controlled reps works well as a hamstring finisher. Stop the set as soon as your straight-line body position breaks down rather than pushing to total fatigue. ### Is the Razor Curl safe for the lower back? It is generally well tolerated when the hips, torso, and head move as one rigid unit and the range stays within your control. Problems usually come from folding at the hips, catching yourself with your hands, or collapsing quickly near the floor, so keep the descent slow and stop when form slips.