Scissor Kick
A scissor kick is a supine bodyweight exercise that alternates the legs while they remain off the floor, challenging hip flexion and trunk control.
Definition and execution
A scissor kick is performed lying face up while the legs alternate above the floor. Variants use vertical fluttering or crossing paths, so the name does not define one mandatory 15–20 cm start height, 45° top angle, two-second cycle or repetition count. Use a controllable range and breathe normally; raising the legs or shortening the range changes the leverage.
ACSM · 2026 resistance-training guidelines
Muscles and measurement
The iliopsoas flexes the thigh at the hip, while rectus abdominis, obliques and transversus abdominis have different trunk and abdominal-wall functions. “Lower abs” is not a separate muscle. Core-exercise EMG research shows task-dependent activity but inconsistent methods and limited evidence for some deep muscles. It does not justify one universal primary/secondary/stabilizer ranking or turn acute activation into proof of strength, endurance or posture improvement.
OpenStax · abdominal-wall anatomy · OpenStax · iliopsoas definition · Oliva-Lozano & Muyor · core-exercise EMG review
HYROX® and back claims
The current HYROX® race includes eight 1 km runs and 100 m Sandbag Lunges, but the rules provide no evidence that scissor kicks preserve pelvic position, prevent anterior tilt, improve running economy, save 10–20 seconds per kilometre or build lunge-specific hip-flexor endurance. Alternating the legs while supine is not the same motor task as running. Keeping the low back against the floor may be a useful coaching constraint for some people, but it does not guarantee spinal protection, and arching does not by itself diagnose insufficient “core” strength.
HYROX® Singles Rulebook 2026/27 · NICE · low back pain recommendations
Programming and alternatives
Scissor kicks can be one optional trunk/hip-flexion drill when suitable and tolerable. Sets, time, range and pace should match the goal and person rather than a universal 3×20-to-40 progression. Reverse crunches, V-ups and sit-ups differ in joint motion and loading; claims that one isolates the lower abdomen, uses fewer hip flexors or is categorically more intense require direct comparison. Pain is a reason to modify or seek assessment, not proof of bad technique alone.
ACSM · 2026 resistance-training guidelines · NICE · low back pain recommendations
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FAQ
How many scissor kicks should I do?
No universal number is established. Choose a controllable range, pace and amount appropriate to your goal and current capacity, and stop before form or symptoms deteriorate.
ACSM · 2026 resistance-training guidelines · NICE · low back pain recommendations · Oliva-Lozano & Muyor · core-exercise EMG review
Are scissor kicks bad for the back?
They are neither universally harmful nor guaranteed safe by pressing the back down. Comfort and tolerance vary; reduce range or stop if symptoms occur, and seek qualified advice for persistent pain.
ACSM · 2026 resistance-training guidelines · NICE · low back pain recommendations · Oliva-Lozano & Muyor · core-exercise EMG review
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