Slump Test: how to detect neural tension in the lumbar spine

When a client describes pain that "runs down the leg" from the back, one of the first questions you need to ask is: is this muscular, joint-related, or neural? The Slump Test is exactly the tool to start answering that question, by assessing how the nervous system behaves when it's progressively put under tension.

It's a test widely used in physical therapy to differentiate pain of neural origin (sciatica, radiculopathy) from other types of mechanical low back pain.

What does this test measure?

The Slump Test assesses the mechanical sensitivity of the nervous system (particularly the sciatic nerve and dura mater) by combining several positions that progressively place tension on the spine and lower limb: trunk flexion, cervical flexion, knee extension, and ankle dorsiflexion.

If the reproduction of the client's symptoms changes when the position of the neck is altered (without touching the leg), it's a strong indication that a neural component is involved.

Equipment needed

• A treatment table or bench where the client can sit with their legs hanging
• Nothing else, though it helps to have paper to record the degree of knee extension if you want to quantify it

Step-by-step protocol

1. The client sits on the edge of the table, hands behind their back (or clasped) and back straight
2. Ask them to flex the entire spine (cervical, thoracic, and lumbar), letting the head drop toward the chest
3. While maintaining that flexion, ask them to actively extend one knee as far as possible
4. With the knee extended, ask for ankle dorsiflexion (bringing the toes toward the shin)
5. Note whether any symptoms appear (pain, tingling, tightness) and where
6. If symptoms appear, ask the client to extend their neck (lift their head) without changing the rest of the position
7. Observe whether the symptoms decrease or disappear when the neck is extended — this is what confirms the neural component

Common mistakes

• Not maintaining spinal flexion throughout the rest of the sequence
• Confusing the normal sensation of hamstring tension (which appears in almost everyone) with the reproduction of specific neural symptoms
• Forcing knee extension when intense pain is already present (the test should be progressive, stopping if clear symptoms appear)

How to interpret the result

Result	Interpretation
Positive: client's symptoms are reproduced and improve when the neck is extended	Suggests nervous system involvement (sciatica, radicular irritation, dural tension)
Positive only with generalized hamstring tension, no change when moving the neck	Likely a muscular, not neural, component — less specific
Negative: no symptoms reproduced at any stage	Doesn't rule out the problem, but reduces the likelihood of a significant neural component at that time

A positive Slump with associated neurological signs (loss of strength, altered reflexes or sensation) should be referred for medical assessment to rule out a significant radicular compression.

Related tests

The Slump Test is part of the family of lumbar spine neurodynamic tests. It pairs well with:

• Straight leg raise test (Lasègue) — another classic neurodynamic test, more focused on the leg in supine position
• Bragard's test — to confirm the neural component of a positive Lasègue

Track progress with Movalytics

Neural tension can improve (or worsen) quite a bit from one week to the next with appropriate treatment. In Movalytics you can record whether the Slump was positive or negative, at which stage the symptoms appeared, and whether they improved with cervical extension, and compare that progression assessment after assessment without relying on memory.

Frequently asked questions

Is the Slump Test painful? It can cause discomfort or tension, especially if there's neural irritation, but it shouldn't cause intense pain. If that happens, the progression is stopped immediately. Is it the same as the Lasègue test? No, although they're related. The Slump is done seated and adds cervical and trunk flexion, making it somewhat more sensitive for detecting overall neural tension. Does a negative Slump rule out sciatica? Not entirely, but it does reduce the likelihood that a neural component is the main driver of symptoms at that time.