Leg Raise: How to Do It Correctly

Step-by-step form

1. Setting up

   Lie flat on your back with legs fully extended and together, ankles in a neutral position (neither pointed nor flexed). Place your hands at your sides with palms down, or tuck them under your glutes for added lumbar support. The lower back maintains light contact with the floor as the pelvis settles into a neutral-to-posterior tilt. The head rests on the floor in a neutral position with the chin slightly tucked, gaze directed at the ceiling.

2. The movement

   Keeping the legs together and knees locked, raise them via hip flexion to roughly 90 degrees over about 1.5-2 seconds. Pause briefly at the top, then lower the legs at a controlled rate down to the point just before the lower back wants to lift off the floor - typically around 30-45 degrees, varying by individual core strength. The descent should run slightly slower than the ascent (2-3 seconds) to emphasize the eccentric loading phase. Stop short of the floor and immediately reverse into the next repetition to keep continuous tension on the target muscles.

3. What stays in line

   Lumbar contact with the floor must be maintained throughout; the pelvis should not tip anteriorly, which is what causes the lower back to arch and lift off the ground. Keep the knees locked in full extension for the entire range - even slight bending reduces hip-flexor torque demand and shifts strain toward hamstring tightness. Shoulders stay flat on the floor with the upper torso stationary; all movement should occur exclusively at the hip joint. Keep ankles neutral - pointing the toes hard adds unnecessary gastrocnemius tension that has nothing to do with the target movement.

4. Breathing

   Exhale through the mouth over 1.5-2 seconds as you raise the legs (concentric phase); pause briefly at the top without holding your breath. Inhale through the nose over roughly 2 seconds as the legs lower (eccentric phase). Avoid breath-holding (Valsalva) since it unnecessarily spikes intra-abdominal pressure and can load the lumbar discs, particularly relevant for anyone with lower-back sensitivity.

Common mistakes

1) Lower back lifting off the floor: Check by sliding a hand under your lumbar spine - if a gap opens up, the pelvis has tipped anteriorly, which is the most common and highest-risk error. 2) Using momentum to swing the legs: If the motion looks jerky or bouncy, the hip flexors aren't doing the work - inertia is; aim to spread each phase over 1.5-2 seconds. 3) Forcing a larger range than control allows: Pushing the legs all the way to the floor once lumbar contact has already broken increases lumbar hyperextension risk - a shorter, clean range beats a longer, compensated one.

Recommended sets and reps

Recommended sets and reps

Beginner: 2 sets x 8-10 reps (bent-knee version recommended). Intermediate: 3 sets x 12-15 reps straight-leg, 2-0-3-0 tempo. Advanced: 3-4 sets x 15-20 reps, or hanging leg raise for 3 sets x 10-12 reps.

Tempo

Beginner: 2-1-2-0 (2 s up, 1 s pause at top, 2 s down, no hold at bottom). Intermediate: 2-0-3-0 (2 s up, no pause, 3 s down - eccentric emphasis). Advanced: 1-2-3-0 (1 s explosive-ish raise, 2 s isometric hold at top, 3 s slow controlled lowering).

How often

Can be programmed 3-4 days per week as core/ab work; since it heavily recruits the hip flexors, avoid stacking high volume of this exercise on the same day as other hip-flexion-dominant work (e.g., high-knee sprint drills). Consecutive-day programming is generally fine since this is a low-to-moderate-load bodyweight core exercise, but allow 24 hours of recovery if lower-back fatigue is noticeable.

What it trains

Builds hip-flexor strength that transfers directly to running stride frequency, climbing, and the knee-drive speed used in kicking sports. Develops isometric endurance in the lower rectus abdominis and internal obliques, improving the capacity to stabilize the pelvis and resist anterior tilt - useful for proper lifting mechanics in daily life. When performed with correct form, it builds pelvic control that supports long-term lower-back health.

If something hurts

Knee

Knee pain during the straight-leg raise is uncommon since the knee is passively locked in extension; the most likely cause is forcing the joint into hyperextension at full lockout. Immediate modification: maintain a very slight 'soft lock' a few degrees short of full extension to reduce joint loading. If pain is sharp or localized under the patella, stop the exercise and consult a healthcare professional.

Lower back

Lower-back pain results from the pelvis tipping anteriorly to counterbalance the weight of the legs, pushing the lumbar spine into hyperextension - this is the single most commonly reported issue with the leg raise. Immediate modification: shrink the range of motion to whatever angle you can control without losing lumbar contact, and bend the knees to shorten the hip-flexor lever arm. If pain doesn't resolve within 1-2 repetitions, radiates into the leg, or is sharp, stop the exercise entirely and consult a healthcare professional.

Shoulder

Shoulder pain is extremely rare in this supine position since no load passes through the shoulder joint; the most likely cause is keeping the hands tucked behind the head or overstretched, which pulls the shoulder into a forward, impinged position. Immediate modification: keep your hands flat at your sides or tucked under your glutes for support rather than behind your head. If pain is sharp or radiates down the arm, stop the exercise and consult a healthcare professional.

When to skip it

Acute lumbar disc herniation or active sciatic nerve irritation confirmed by a positive straight-leg-raise test (this exercise loads the same position used in that diagnostic test and can provoke symptoms). Acute hip-flexor strain or tendinopathy. Uncontrolled diastasis recti or early postpartum core dysfunction (the flexion-based loading places pressure on the linea alba). Advanced pregnancy (due to prolonged supine positioning and increased intra-abdominal pressure).

Where to go next

Moves that train the same thing — and, where this one sits on a ladder, the rungs either side of it.

• Seated Knee Tuck→
• Step-up→
• Wide Table Inverted Row→
• Bicycle Crunch→
• Decline Push-up→
• Diamond Push-up→