Waist left/right training

Each photo shows one side of a person’s waist, the area between the lower ribs and the top of the hips. Decide whether it is their own left side or right side. Answer as quickly as you comfortably can.

What this exercise asks

This is a body-side recognition task: the same kind of question as deciding whether a picture shows a left hand or a right hand. You are not judging which way the person is turned, leaning or looking. You are identifying which side of their body you can see. The direction of the head, the eyes or any movement doesn’t change the answer.

How to do it

1. Find the waist, the band between the bottom of the ribs and the top of the hips, and decide whether you are looking at the person’s own left or right side.
2. Keep sets short. A set of 20 takes about a minute. Rest between sets if you need to.

This kind of exercise is also called left/right discrimination, laterality training or implicit motor imagery. New to this? Start with no time limit and feedback on. The beginner’s guide explains how to build up slowly and what your scores mean.

Who might find this useful

You don’t need a diagnosis to try this. If your lower back, sides, hips or pelvis have been sore, stiff or “guarded” for three months or more, that counts as long-term (chronic) pain, even if no one has called it that. Most research on left/right judgements of the trunk has been done in people with back pain. For the other groups below, studies show that the brain’s sense of that area or the way it is controlled can change, but left/right training itself hasn’t been tested there. Treat this as a reasonable, low-effort thing to try, not a proven treatment.

• Chronic low back pain. People with back pain were less accurate at judging pictures of the trunk, but not pictures of hands, and those with pain on both sides were the least accurate.¹ A study of 150 people with chronic low back pain also found them slower and less accurate than people who had never had back pain.² One smaller study found no difference,³ so the results are mixed.
• Back pain that keeps coming back. In an online study of 1,008 people, those with a history of back pain who were in a flare-up at the time were the least accurate.⁴ Another study found that people who had back pain in the past, but were pain-free when tested, performed about as well as people with chronic back pain, which suggests the changes may outlast the pain.²
• Muscle imbalances and left–right asymmetry, such as one side feeling tighter, weaker, “switched off” or harder to sense. People with pain on one side of the back were less accurate at trunk judgements than people without pain.¹ In a small study, people with chronic back pain could not clearly sense the outline of their back where it hurt, and their sense of touch was less sharp in the same area.⁵ Practising telling the two sides apart is a natural fit for this, but it hasn’t been tested as a treatment for asymmetry.
• Sacroiliac (SI) joint and pelvic girdle pain, including pain that started during or after pregnancy. People with SI joint pain used different bracing and breathing strategies during a simple leg lift,⁶ and women with long-lasting pregnancy-related pelvic and low back pain reported a more disturbed sense of their back and pelvis.^7,8 No studies have tested left/right training for this group yet.
• Tense or held breathing. The waist sits over the lower ribs and the diaphragm, the main breathing muscle. In one small study, half the people with chronic low back pain changed their breathing pattern, for example by holding their breath, during simple movement-control tests, whatever their pain level.⁹ Left/right training hasn’t been tested for breathing, but noticing whether you brace or hold your breath during a set is useful in itself.
• Scoliosis. One small study of 25 people with scoliosis found that the direction of the curve may be linked with how quickly they judged some left/right pictures, but it had no comparison group.¹⁰ The evidence here is very limited.
• Fibromyalgia and widespread pain. People with fibromyalgia were slower and less accurate at left/right judgements.¹¹

No trial has tested trunk left/right training on its own. The largest related trial, in 276 people with chronic low back pain, tested a 12-week programme combining pain education, training to sharpen the sense of the back, mentally rehearsing movement and graded exercise. Pain improved by a small amount (about 1 point on a 0–10 scale) more than with a fake treatment.¹² That programme didn’t use left/right photos, so it can’t tell us how much this exercise adds on its own.

If your pain is mainly in your neck or head, try the neck exercise; for the jaw or face, try the jaw exercise. Tools for the hands, feet and other areas are planned.

About the photos

There are 60 photos of adults of different ages and backgrounds, seen from the front, the side and behind, standing, sitting and kneeling. Half show the left side of the waist and half the right. With mirrored photos switched on, each photo can also appear flipped, which reverses the answer, so there are 120 possible images. Each set is drawn at random, never shows the same photo twice, and favours photos you haven’t seen recently. Every photo has been checked against its answer.

All photos are AI-generated. They don’t show real people.

Common questions

What counts as a good score?

There are no published averages for this exact exercise. In studies that used pictures of the trunk turning or bending, people without back pain got about 84% to 87% right.^1,4 That was a different task, so treat it as a rough guide. Comparing your own results over time, and your left with your right, is more useful.

Why judge the side of the body rather than which way it is turned?

Most published trunk exercises ask which way the body is turned or bent. This one asks which side of the body you are looking at, like telling a left hand from a right hand. The two are closely related, and both rely on your brain matching the picture to your own body. Some researchers have questioned whether trunk pictures work in quite the same way as hand pictures,¹³ and this exact version hasn’t been tested in its own study.

Why is one side harder for me?

Many people are a little better at one side. A clear, steady gap between your left and right results is worth mentioning to your clinician. Small differences from day to day are normal.

Does this work on a phone?

Yes. Tap the Left or Right button under the photo. Each set loads only the photos it needs, about 1 MB for 20.

Where are my results stored?

Only in your browser, on this device. Nothing is sent to us. Clearing your browser data removes them. Your results for each exercise are kept separately.

References

1. Bray H, Moseley GL. Disrupted working body schema of the trunk in people with back pain. British Journal of Sports Medicine. 2011;45(3):168–173. Link
2. Matheve T, Janssens L, Timmermans A, Goossens N, Danneels L, Meirezonne H, Brandt M, De Baets L. Trunk laterality judgement in chronic low back pain: influence of low back pain history, task complexity, and clinical correlates. Journal of Clinical Medicine. 2025;14(15):5328. Link
3. Linder M, Michaelson P, Röijezon U. Laterality judgments in people with low back pain – a cross-sectional observational and test-retest reliability study. Manual Therapy. 2016;21:128–133. Link
4. Bowering KJ, Butler DS, Fulton IJ, Moseley GL. Motor imagery in people with a history of back pain, current back pain, both, or neither. The Clinical Journal of Pain. 2014;30(12):1070–1075. Link
5. Moseley GL. I can’t find it! Distorted body image and tactile dysfunction in patients with chronic back pain. Pain. 2008;140(1):239–243. Link
6. O’Sullivan PB, Beales DJ, Beetham JA, et al. Altered motor control strategies in subjects with sacroiliac joint pain during the active straight-leg-raise test. Spine. 2002;27(1):E1–E8. Link
7. Beales D, Lutz A, Thompson J, Wand BM, O’Sullivan P. Disturbed body perception, reduced sleep, and kinesiophobia in subjects with pregnancy-related persistent lumbopelvic pain and moderate levels of disability: an exploratory study. Manual Therapy. 2016;21:69–75. Link
8. Wand BM, Elliott RL, Sawyer AE, et al. Disrupted body-image and pregnancy-related lumbopelvic pain. A preliminary investigation. Musculoskeletal Science and Practice. 2017;30:49–55. Link
9. Roussel N, Nijs J, Truijen S, Vervecken L, Mottram S, Stassijns G. Altered breathing patterns during lumbopelvic motor control tests in chronic low back pain: a case–control study. European Spine Journal. 2009;18(7):1066–1073. Link
10. Candiri B, Ramazanoğlu E, Adlı H, Talu B, Çoban İ, Aslantürk O, Ceylan MF. Right left discrimination performance of body parts in individuals with scoliosis. İnönü Üniversitesi Sağlık Hizmetleri Meslek Yüksekokulu Dergisi. 2024;12(2):436–448. Link
11. Martínez E, Guillén V, Buesa I, Azkue JJ. A distorted body schema and susceptibility to experiencing anomalous somatosensory sensations in fibromyalgia syndrome. The Clinical Journal of Pain. 2019;35(11). Link
12. Bagg MK, Wand BM, Cashin AG, et al. Effect of graded sensorimotor retraining on pain intensity in patients with chronic low back pain: a randomized clinical trial. JAMA. 2022;328(5):430–439. Link
13. Alazmi L, Gadsby GE, Heneghan NR, Punt TD. Do trunk-based left/right judgment tasks elicit motor imagery? Musculoskeletal Science and Practice. 2018;35:55–60. Link