Lying Straight Leg Raises
You lie on your back with your hands under your glutes, legs straight and heels just clear of the floor. From there you lift both legs to roughly vertical, hold for a beat and lower them slowly until your heels are just clear of the floor again.
The lying straight leg raise is core work on the floor. You lie on your back and lift both straight legs to roughly vertical.
Your hip flexors and rectus femoris do the lifting, with the adductors helping. Your abdominal wall has a different job: it holds the pelvis in place so your lower back stays flat on the floor.
The lower your legs travel, the longer the lever and the bigger the load at the hip. That last hand's width above the floor is where the exercise gets hard.
All you need is the floor. You progress by going further down and by staying in control the whole way.
Starting position
Lie flat on your back. Slide your hands palm-down under your glutes — they support your pelvis and help keep your lower back on the floor. Rest your head on the floor and keep your neck long.
Straighten your legs and lift your heels a hand's width off the floor. That's the starting position, and every rep comes back to it.
Lift both straight legs until they are roughly vertical and hold there for a beat. Then lower them slowly and stop a hand's width above the floor. The next rep starts from there. Your lower back stays flat on the floor throughout.
The three cues
- Hands under your glutes, lower back flat on the floor
- Legs long, heels together
- Stop a hand's width above the floor
Common faults
| Fault | How to fix it |
|---|---|
| Your lower back arches up off the floor | Stop your legs while your back is still flat and work in that shorter range. The range grows as your control improves. |
| Your knees bend on the way down | Keep your legs long and your heels together. Drawing your kneecaps up towards your hips keeps your knees straight. |
| Your heels touch down and the next rep starts with a swing | Stop a hand's width above the floor and start the next rep calmly from there. |
| Your chin pulls towards your chest | Rest your head on the floor, keep your neck long and look at the ceiling. |
Variations
| Variation | When to use it |
|---|---|
| One leg at a time | Keep one foot planted on the floor, lift the other leg straight, then lower it slowly. Move on once your lower back stays flat throughout. |
| Both legs, knees bent | Bend your knees to about 90 degrees and lift and lower both legs together. The shorter lever makes it easier to keep your pelvis steady. |
| Both legs straight | Lower your straight legs from vertical to a hand's width above the floor and lift them back, at a calm tempo with your lower back flat. |
| Lower and slower | Lower further and take longer over it, for as long as your lower back stays flat on the floor. |
Reps and load
Andreas's tempo: two seconds up, a beat at the top, a good two seconds down, then a beat at the bottom before the next rep.
Put this in the core part of the session, after the big lifts. The set is over once your lower back lifts off the floor. That's your cut-off.
Which muscles do the work
| Muscle | Role | What it does here |
|---|---|---|
| Iliacus M. iliacus | Prime mover | Lifts your thigh towards your trunk |
| Rectus femoris M. rectus femoris | Prime mover | Flexes the hip while keeping the knee straight |
| Adductor longus M. adductor longus | Synergist | Helps lift the straight leg and keeps the legs together |
| Rectus abdominis M. rectus abdominis | Synergist | Tilts the pelvis back so your lower back stays on the floor |
| External oblique M. obliquus externus abdominis | Synergist | Holds the abdominal wall firm, especially when your legs are low |
| Internal oblique M. obliquus internus abdominis | Synergist | Tightens the abdominal wall from the inside and keeps the pelvis still |
| Psoas major M. psoas major | Stabiliser | Runs from your lumbar spine to your thigh and keeps your spine steady in this position |
| Vasti Mm. vasti | Stabiliser | Keeps the knee straight through the whole rep |
Your hip flexors and rectus femoris lift your straight legs, with the adductors helping. Your abdominal wall holds your pelvis steady and keeps your lower back down on the floor. The psoas major runs from your lumbar spine to your thigh and keeps your spine steady in this position.
Seeing it done right is not the same as doing it right
Video, cues and variations take you a long way. What they cannot give you is an outside eye at the moment the movement isn't quite there yet. That is what training with me is for — in the studio or in a workshop.
See the workshopsNew exercise pages are added all the time — the newsletter keeps you posted.
Sources
Hu H, Meijer OG, van Dieën JH, Hodges PW, Bruijn SM, Strijers RL, Nanayakkara PW, van Royen BJ, Wu WH, Xia C. (2011). Is the psoas a hip flexor in the active straight leg raise? Eur Spine J 20(5):759–765. DOI: 10.1007/s00586-010-1508-5 — Measures which muscles lift the straight leg in 17 healthy women aged 20 to 40, using fine-wire electrodes in psoas and iliacus and surface electrodes on rectus femoris and adductor longus. Iliacus and rectus femoris behaved like hip flexors, and adductor longus was involved and switched on early — the basis for the roles in the muscle table. Psoas behaved bilaterally and the authors read it as a stabiliser of the lumbar spine rather than a hip flexor, which is why it sits under stabiliser here. The single-leg raise was tested, not the two-legged version. Young women only, training status not reported, no data for people aged 40 to 60. (Evidence type: EMG)
Shields RK, Heiss DG. (1997). An electromyographic comparison of abdominal muscle synergies during curl and double straight leg lowering exercises with control of the pelvic position. Spine 22(16):1873–1879. DOI: 10.1097/00007632-199708150-00012 — Compares rectus abdominis and both obliques in 15 healthy men during a curl and during double straight leg lowering, with pelvic position held by an electrogoniometer. With the pelvis held, abdominal activity during leg lowering was clearly higher than during the curl. The basis for saying the abdominal wall works here without the trunk curling up. Young healthy men only, no age range given, no bearing on the Academy's target group. Surface EMG, a snapshot that says nothing about muscle growth. (Evidence type: EMG)
Workman JC, Docherty D, Parfrey KC, Behm DG. (2008). Influence of pelvis position on the activation of abdominal and hip flexor muscles. J Strength Cond Res 22(5):1563–1569. DOI: 10.1519/JSC.0b013e3181739981 — Measures how pelvic position changes things in 16 men holding both straight legs isometrically about five centimetres above the board. With the pelvis tilted back, upper and lower rectus abdominis activity was higher than with it tilted forward. The basis for putting the flat lower back and the hands under the glutes on the page as a condition. Rectus femoris activity did not change with pelvic position, so pelvic control shifts the abdominal share rather than the hip flexor share. No age reported, men only, no bearing on the target group. (Evidence type: EMG)
Haladay DE, Denegar CR, Miller SJ, Challis J. (2015). Electromyographic and kinetic analysis of two abdominal muscle performance tests. Physiother Theory Pract 31(8):587–593. DOI: 10.3109/09593985.2015.1062945 — Combines surface EMG with a calculation of hip joint moment during double leg lowering in 10 healthy people. The hip moment was very closely related to how far the legs had been lowered: the nearer the floor, the larger it was. The basis for saying that the last hand's width above the floor sets the difficulty. A very small sample, with sex and age not reported in the abstract. What was calculated is the moment at the hip, not a load on the lumbar spine. (Evidence type: EMG und Kinetik)
Filho RF, de Brito Silva P, Ito MA, Alves N, Padovan CR, Mícolis de Azevedo F. (2006). Stabilization of lumbo-pelvic region and electromyography of the abdominal muscles. Electromyogr Clin Neurophysiol 46(1):51–57. PMID 16607867. — Measures abdominal activity, hip angle and the pressure under the lumbar spine in 18 men (19.3 ± 3.5 years) with no complaints, during double straight leg lowering. None of the 18 held the lower back flat through the whole movement, even though all had passed the pelvic tilt test beforehand. The basis for making the flat back the gate and ending the set there rather than at a rep count. The observation that the external oblique works harder between 70 and 20 degrees of hip flexion is reported as a tendency, not as a tested difference. Very young men, no bearing on the target group. No DOI is registered for this paper; verified via PubMed. (Evidence type: EMG)
Dostal WF, Soderberg GL, Andrews JG. (1986). Actions of hip muscles. Phys Ther 66(3):351–359. DOI: 10.1093/ptj/66.3.351 — Calculates moment arms for 27 hip muscle segments in three planes at 0, 40 and 90 degrees of hip flexion, using a skeletal specimen. With the leg straight the adductors carry a flexion component that changes with hip angle — the basis for listing adductor longus as a synergist in the table. A model built on a single bone specimen, with no living subjects and no measurement of whether the muscle is actually recruited in this exercise; Hu 2011 sits alongside it for that. (Evidence type: Biomechanisches Modell)
Guimaraes AC, Vaz MA, De Campos MI, Marantes R. (1991). The contribution of the rectus abdominis and rectus femoris in twelve selected abdominal exercises. An electromyographic study. J Sports Med Phys Fitness 31(2):222–230. PMID 1836517. — Compares twelve abdominal exercises in 20 physical education students. Leg raising from a supine position produced clearly less upper rectus abdominis activity than every other exercise tested, and whether the knees were bent or straight did not change rectus abdominis activity. The basis for presenting the bent-knee version on this page as a change of lever, and the abdominal wall as what holds the pelvis rather than as the prime mover. A young, physically active sample, surface EMG. No DOI is registered for this paper; verified via PubMed. (Evidence type: EMG)
Youdas JW, Garrett TR, Egan KS, Therneau TM. (2000). Lumbar lordosis and pelvic inclination in adults with chronic low back pain. Phys Ther 80(3):261–275. DOI: 10.1093/ptj/80.3.261 — Looks at 60 adults (30 men, 30 women, mean age 54.9, range 40.4 to 69.8) with long-standing back complaints, plus a comparison group. Those who lost control beyond 50 degrees (men) or 60 degrees (women) during double leg lowering more often had long-standing back complaints. The only paper in this block whose age group matches the Academy's readership; the basis for treating this exercise as a step with a prerequisite and for offering the earlier stages. An observation at one point in time, not proof of cause and effect, and no evidence that an earlier stage changes the complaints. (Evidence type: Querschnitt)
A note on context: EMG studies show which muscles an exercise recruits — that is a good reason to pick it, but it does not replace adjusting things to the person in front of you. See a doctor for persistent or severe pain.