Active Straight Leg Raise Test (aSLR)

Original Editor - Riccardo Ugrin Top Contributors - Riccardo Ugrin and Lucinda hampton

Background[edit | edit source]

The Active Straight Leg Raise (aSLR) is a test used to assess load transference through the pelvis. It is an important test in diagnosing Pelvic Girdle Pain (PGP).[1] PGP can affect; pregnant women; athletes with groin pain; can occur after a trauma.

The aSLR test is considered positive when it elicits pain in the lumbo-pelvic region or it points out a Motor Control (MC) dysfunction.

Some study also suggests that the aSLR test should be used with other functional evolution tests to isolate the cause of Low Back Pain[2].

Clinical observations also show that patients with sacroiliac joint pain have suboptimal MC strategies and alterations in respiratory function when performing low-load tasks such as an active straight leg raise[3].

For more information please see Recognising Pelvic Girdle Pain

Purpose[edit | edit source]

In the past it has been suggest that patients with PGP lack the ability to stabilize the pelvic girdle, probably due to instability or increased movement of the sacroiliac joint.[4] However a more recent study contradict the hypothesis that a forward rotation of the lifted leg's joint occur while performing the aSLR.[5]It is more reasonable that aSLR does not evaluation test the stability of sacoiliac joint but is a stress-test for the capacity to transfer the load between legs and lumbo-pelvic structures. As a matter of fact during testing, assessment of the primary subjective feature of heaviness of the leg (or pain) is complimented by observation of motor control (MC) adaptations such as respiratory disruption and abdominal bracing[6][3]. Furthermore some studies[7] investigated the biomechanical models and their connection with lumbopelvic stability. Accordingly to that, literature supports the hypothesis of aberrant MC patterns providing a mechanism for ongoing pain in specific PGP presentations.

Technique[edit | edit source]

The classic straight leg raise is a complete active test. Each leg is tested individually. Test the uneffected side first.

  • When performing the aSLR test, the patient is positioned in supine without a pillow under his/her head.
  • The starting position is described with a distance of 20cm between feet.
  • The patient must rise the leg 20cm from the starting position maintaning the knee in complete extension.
  • Then patient is asked to rate their fatigue during each aSLR in a score from 0 to 5, without taking into consideration pain.
  • The test is considered positive when the subjective feeling of fatiguq is >3.

Although the aSLR test is also considered positive when it elicits pain in the lumbo-pelvic region or it point out a Motor Control (MC) dysfunction. If the test is positive for pain, it could be effective re-assess the aSLR offering a manual compression through the iliac bones or use a belt to stabilize the pelvis. If the pain is reduced with compression, this can guide the physical examination to the hypothesis of MC deficit instead of a sacroiliac joint assessment.

Active Straight Leg Raise [8]

The elevate position could be maintained for a few seconds if needed. That could be usefull to evaluate the endurance of muscles or the capacity to control the position.

Clincal Considerations[edit | edit source]

  • The ASLR consists of ipsilateral hip flexion, a contralateral hip extension moment, force closure by the lateral abdominal muscles, sagittal plane pelvis stabilization by the abdominal wall, and activity of contralateral transverse plane rotators of the pelvis.
  • It is demonstrate that Internal Abdominal Oblique (IO) has a major activation in EMG ipsilateral [9][10]. Indeed it seems that transversus abdominis (TrA) and rectus abdominis (RA) are more asymmetrically active than obliquus externus.
  • It is shown a major activatin of the contralateral Biceps Femoris (BF) in EMG in opposition to the activation of ipsilateral Rectus Femoris (RF)[11]
  • In patient with LBP, PGP or groin pain the force expressed in hip flexion is considerably less than in healthy subjects. This seems to be in opposition with the greater activation showed in EMG studies for the hip flexors during an aSLR test. In spite of that during lifting of the leg in combination with loss of effort to rise the leg, seem to indicate that LBP and PGP patients try hard to lift a leg but they are less able to do so.[12]
  • Overactivation of the superficial abdominal musculature may be an attempt at the neuro-motor system to make up for the deficit expressed by the IO musculature. Indeed is demonstrated that thickness (and probably the strength expressed) of the TrA is significantly reduced compared to what was found in healthy subjects [13]
  • From the studies considered, it also emerges that high scores on the ASLR test, which indicate a important functional impairment, are related to high scores on disability perception. [14]
  • A study investigated changes in respiratory chinematics, diaphragm movements and the analysis of the pelvic floor during the aSLR test. An altered diaphragmatic function during the aSLR is observed in patients with Sacroiliac Joint Pain and may represents an attempt by the neuromuscular system to compensate the lack of "form closure". In this case, the normal functionality of the diaphragm in the respiratory mechanics is altered, allowing the diaphragm to stabilize the lumbo-pelvic region through the control of the intra abdominal pressure.[3] The same study also shows a greater lowering of the pelvic floor during aSLR. This little drop can represent the mechanism to maintain the intra abdominal pressure constant in respond to the diaphragm.

Whiteboard Talks: Understanding the ASLR [15]

  • However the aSLR test is not sufficient to keep diagnosis of inefficient MC. Other tests are available to confirm, or falsify, the clinical hypothesis that the patient is having problems with force closure.

Evidence[edit | edit source]

The aSLR test has a good sensibility and reliability. Studies investigate the clinical reliability and validity of the the aSLR test in patients with persistent pelvic girdle pain related to pregnancy[16]. They performed a cross-sectional analysis of the aSLR compared to the posterior thigh thrust and found the sensitivity to be 0.87 and specificity to be 0.94.[17]

Resources[edit | edit source]

  1. Hu H, Meijer OG, Hodges PW, Bruijn SM, Strijers RL, Nanayakkara PWB, van Royen BJ, Wu W, Xia C, van Dieën JH. Understanding the Active Straight Leg Raise (ASLR): An electromyographic study in healthy subjects. Manual Therapy, 2012; 17(6):531–537.
  2. Krkeljas Z, Kovac D. . Relationship between ASLR and motor control impairment tests in physically active individuals with and without low back pain. (2018); 8: 5-15.
  3. 3.0 3.1 3.2 O'Sullivan PB, Beales DJ, Beetham JA, Cripps J, Graf F, Lin IB, Tucker B, Avery A. Altered motor control strategies in subjects with sacroiliac joint pain during the active straight-leg-raise test. Spine (Phila Pa 1976). 2002 Jan 1;27(1):E1-8
  4. Mens JM, Vleeming A, Snijders CJ, Stam HJ, Ginai AZ. The active straight leg raising test and mobility of the pelvic joints. Eur Spine J. 1999;8(6):468-73.
  5. Kibsgård TJ, Röhrl SM, Røise O, Sturesson B, Stuge B. Movement of the sacroiliac joint during the Active Straight Leg Raise test in patients with long-lasting severe sacroiliac joint pain. Clin Biomech (Bristol, Avon). 2017 Aug;47:40-45
  6. Beales DJ, O'Sullivan PB, Briffa NK. Motor control patterns during an active straight leg raise in chronic pelvic girdle pain subjects. Spine (Phila Pa 1976). 2009 Apr 20;34(9):861-70.
  7. Snijders C, Vleeming A, Stoeckart R. Transfer of lumbosacral load to iliac bones and legs, part 1: biomechanics of self-bracing of the sacroiliac joints and its significance for treatment and exercise. Clin Biomech 1993;8:285–94
  8. Active Straight Leg Raise. Available from:
  9. Teyhen DS, Williamson JN, Carlson NH, Suttles ST, O'Laughlin SJ, Whittaker JL, Goffar SL, Childs JD. Ultrasound characteristics of the deep abdominal muscles during the active straight leg raise test. Arch Phys Med Rehabil. 2009 May;90(5):761-7.
  10. Linek P, Saulicz E, Wolny T, Myśliwiec A. Intra-rater reliability of B-mode ultrasound imaging of the abdominal muscles in healthy adolescents during the active straight leg raise test. PM R. 2015 Jan;7(1):53-9
  11. Beales DJ, O’Sullivan PB, Briffa NK. “The effect of increased physical load during an active straight leg raise in pain free subjects”, Journal of Electromyography and Kinesiology 20 (2010) 710–718.
  12. Jansen J, Weir A, Dénis R, Mens JMA, Backx F, Stam HJ. “Resting thickness of transversus abdominis is decreased with longstanding adduction-related groin pain”, Man Ther, 2010; 15: 200-205.
  13. De Groot M, Pool-Goudzwaard AL, Spoor CW, Snijders CJ. “ The active straight leg raising test (ASLR) in pregnant women: differences in muscle activity and force between patients and healthy subjects”, Man Ther, 2008; 13: 68-74.
  14. Ronchetti I, Vleeming A, van Wingerden JP. “Physical characteristics of women with severe pelvic girdle pain after pregnancy”, Spine 2008; 33: E145-E151.
  15. Whiteboard Talks: Understanding the ASLR. Available from:
  16. Mens, J. M., Vleeming, A., Snijders, C. J., Koes, B. W., & Stam, H. J. (2001). Reliability and validity of the active straight leg raise test in posterior pelvic pain since pregnancy. Spine, 26(10), 1167-1171.
  17. Mens JM, Pool-Goudzwaard A, Beekmans RE, Tijhuis MT. Relation between subjective and objective scores on the active straight leg raising test. Spine (Phila Pa 1976). 2010 Feb 1;35(3):336-9