reckonerSliding leg curl
Lie on your back with your heels on something that slides, lift your hips, then push the heels out and drag them back in. No machine, no weight. Your hamstrings are holding your hips up and bending your knees at the same time, which is why it gets hard so quickly.
Heels slide out. Hips stay up.
- Pattern
- Knee isolation
- Trains
- Hamstrings
- Kit
- Bodyweight, floor
- Loading
- Your own bodyweight
- Reckoner prescribes
- 3 sets of 10 to 15 reps at RPE 8
- Progression step
- Nothing to add, so the sets climb instead
- Skill
- Some technique
- Recovery cost
- Low
Muscles worked
How to do it
Find a surface and something to slide on
Furniture sliders, a towel on a hard floor, socks on laminate. It has to slide freely. On carpet this movement does not work and forcing it just grinds your heels.
Lie on your back with your heels on the sliders
Knees bent, arms flat at your sides for balance. Push your hips up until your body makes a straight line from knee to shoulder.
Heels slide out. Hips stay up
That is the cue on your wrist and both sentences are the exercise. Push the heels away until the legs are nearly straight, and do not let your backside sink toward the floor while they travel.
Drag the heels back in
Pull them back under your knees, keeping the hips high the whole time. Then go again without resting on the floor between reps.
What goes wrong
Letting the hips drop as the heels go out
This is the whole difficulty and the whole point. When the hips sink, the hamstrings have stopped holding hip extension and the movement becomes a slow knee bend with nothing much resisting it. Shorten how far the heels travel until you can keep the hips up for every rep.
Going fast on the way out
Sliding out quickly means the hamstrings never controlled the lengthening part, which is the half of the rep that is hardest to fake and most worth having. Push out slowly enough that you could stop anywhere.
Trying it on carpet
It is not a technique problem. On a surface that grips, the heels stick and release rather than sliding, and the movement turns into a series of small jerks. Find a hard floor or a different exercise.
How Reckoner progresses this lift
Six weeks of this lift, run through the real engine. Nothing below was typed in: the prescription, the decision and the sentence beside it all come from the same code that writes your week.
| Week | Prescribed | What it did |
|---|---|---|
| 1 | 3 x 10 | More reps 10 → 11 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does. |
| 2 | 3 x 11 | More reps 11 → 12 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does. |
| 3 | 3 x 12 | More reps 12 → 13 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does. |
| 4 | 3 x 13 | More reps 13 → 14 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does. |
| 5 | 3 x 14 | Deload 40% of sets offFive weeks of building, then one week lighter. About 40% of the sets come off. The load holds and your reps stay where you earned them, so you keep the strength and lose the fatigue. |
| 6 | 2 x 14 | More reps 14 → 15 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does. The lighter week is over, so this is back to three sets. |
Real engine output, not an illustration. Every row was produced by running the engine itself when this page was generated.
The full rule, and why the reps move before the load does, is in how Reckoner decides to add weight.
Questions people ask
How do I make this easier or harder?
How far the heels travel is the dial. A short slide is much easier than a long one, so shorten it until you can hold the hips up for every rep and let the range grow from there. Slowing the outward half down is how you make it harder without any kit.
Is this a substitute for a leg curl machine?
It is a real knee bending hamstring exercise for somebody with no machine, and it also asks the hips to stay extended, which a machine curl does not. What it cannot do is load progressively: there is no weight to add, so it has a ceiling.
Will Reckoner take this out of my plan for an injury?
No. The library records no restrictions against it, unlike the Nordic curl, which records a knee restriction.
Similar movements
There is no load to ease on this lift, so Reckoner offers one of these the first time it stalls. Each of them has a page.