Flat Bench Lying Leg Raise
Flat on a bench, hands anchored, you lift both straight legs from below bench height to vertical and lower them under control. Straightening the legs turns them into one long lever, which is why this is far harder than a bent-knee tuck and why the lower back is the first thing to give out.
Own the movement
Set up first, then execute. Every cue below is something you can check on your next set.
Before the first rep
- Lie with your hips at the very end of the bench so the legs can drop clearly below bench level.
- Slide your palms under your glutes or grip the bench edge behind your head; you need a real anchor, not a token one.
- Press your lower back into the bench and hold that flat position before the legs move at all.
- Start with the legs raised about 30 degrees rather than fully down until you know where your back gives out.
Every rep
Breathing & tempo — Exhale as the legs rise, inhale as they lower, and keep the ribs pulled down through both. Two seconds up, one-second hold at the top, four seconds down.
Sets, reps & load
Where to start, and what to change when it stops being hard.
Bodyweight is enough for most people for a long time. Progress in this order: bend the knees less, then extend the bottom range lower, then slow the lowering to 5 seconds, and only then hold a 2-4 kg dumbbell between the feet. Ten strict reps with a 4-second descent and a flat back is a genuinely strong standard.
What goes wrong
The errors that show up most often, and the cue that fixes each one.
Shorten the bottom range to whatever depth keeps the back flat, and rebuild from there over a few weeks. A hand slid under your lumbar spine gives instant feedback on where that point is.
Count four seconds down and pause a full second at the bottom. If you cannot control four seconds, bend the knees to shorten the lever until you can.
Finish each rep by pushing the heels toward the ceiling until the hips lift a couple of centimetres off the bench. That last inch is where the abs actually shorten.
Keep the elbows relaxed and the shoulders down. The hands are there to stop you sliding, not to help lift — if they are working, the set is beyond you.
Why bother
Two legs held straight put their combined mass roughly a metre from the hip joint. That lever is the load — no plates required. The abs are not lifting the legs so much as stopping the pelvis from being dragged into an arch by them, which is exactly the job they do under a heavy bar.
The bench matters for the same reason it does in the leg pull-in: the legs can travel below hip level, so the anti-extension demand is highest at the bottom, precisely where most people cheat by bouncing off a wobble of the lower back.
Where it fits
Late in a lower-body or full-body session, 2-3 times a week. If your lower back is already fatigued from deadlifts, skip it that day — the position it protects against is the same one deadlifts already stress. It pairs well with a cable crunch, which loads flexion from the top down and covers the range this one does not.
If this one isn't it
No kit, too hard, or too easy — here's where to go instead.
Same job, different kit
Start here instead
When this gets easy
Asked and answered
Straight legs or bent knees?
Bent knees when you cannot hold the lower back flat with straight ones, straight legs the rest of the time. The knee angle is your load dial: every degree you straighten lengthens the lever and increases the demand. There is no virtue in straight legs bought with an arched back.
Is this better than the hanging version?
It is more accessible, not better. Hanging removes the bench's support and adds grip and shoulder demand, which is why it is harder and why most people cheat it with a swing. Earn 12 strict reps here before you take the movement to a bar.
Why do my hip flexors cramp?
The psoas is doing most of the lifting through the first 90 degrees, and it cramps when it is short, weak or already fatigued from squatting. Warm up with a few slow dead bugs, keep the range where the abs are working, and do not schedule this after heavy front squats.
How many should I be able to do?
Ten reps with straight legs, a four-second descent and a back that never leaves the bench is a solid standard for a trained lifter. If you can do 30, you are almost certainly using the bottom bounce; slow it down and the number will collapse to something honest.