NAG and SNAG Techniques: Definition, Steps, Benefits, and Evidence (Mulligan Concept)

NAG and SNAG Techniques: Definition, Steps, Benefits, and Evidence (Mulligan Concept)

The Mulligan Concept, developed by Brian Mulligan, is one of the most widely used manual therapy approaches for treating musculoskeletal pain and restricted movement. Two of its key techniques—NAG (Natural Apophyseal Glide) and SNAG (Sustained Natural Apophyseal Glide)—are especially effective for spinal dysfunctions, joint stiffness, and movement-related pain.

What Are NAG and SNAG Techniques?

NAG (Natural Apophyseal Glide)

NAG is a manual oscillatory mobilization applied to the facet joints (apophyseal joints) of the spine—mainly the cervical and upper thoracic levels.

How it works

  • The therapist applies a forward-upward (anterior + cranial) glide to the articular pillar.

  • The glide is rhythmic, pain-free, and passive.

  • It targets joint stiffness, facet hypomobility, and pain.

Best for:

  • Cervical stiffness

  • Painful cervical ROM

  • Cervical spondylosis

  • Postural neck pain

  • Cervicogenic headache (early steps)

SNAG (Sustained Natural Apophyseal Glide)

SNAG is a sustained facet joint glide applied during the patient’s active movement.

How it works

  • The therapist sustains a glide on the joint.

  • The patient actively performs the restricted or painful movement (e.g., rotation, flexion).

  • The movement should become pain-free and smoother.

Best for:

  • Cervicogenic headaches

  • Limited cervical or lumbar rotation

  • Lumbar flexion/extension pain

  • Thoracic stiffness

  • Rib dysfunction

  • Peripheral joint restrictions (e.g., hip, ankle)


NAG and SNAG technique

Mechanism of Action (How They Work)

✔ Corrects minor positional faults

Joint glides realign subtle facet dysfunction.

✔ Enhances proprioception and mechanoreceptor activation

Reducing pain via spinal inhibition pathways.

✔ Improves synovial fluid distribution

Enhances joint lubrication and nutrition.

✔ Provides immediate pain relief

Due to neurophysiological and biomechanical effects.

✔ Increases ROM, especially in rotation and extension.

Clinical Indications

NAG

  • Cervical stiffness

  • Cervical spondylosis

  • Posture-related pain

  • Myofascial tightness

  • Initial stages of cervicogenic headache

SNAG

  • Cervicogenic headache

  • Limited cervical rotation

  • Lumbar pain and restricted flexion/extension

  • Thoracic hypomobility

  • Rib dysfunction

  • Peripheral joint stiffness (ankle, hip)

Contraindications

Avoid or modify if the patient has:

  • Acute fracture

  • Malignancy

  • Severe osteoporosis

  • Active inflammation

  • Spinal infection

  • Spinal instability

  • Post-surgical restrictions

PubMed-Supported Evidence for NAG & SNAG

1. SNAGs for Cervicogenic Headache

SNAG mobilization significantly improved:
✔ Pain
✔ Cervical ROM
✔ Disability scores (NDI)
Source: J Orthop Sports Phys Ther, 2016.
PubMed: PMID: 26928712

2. SNAGs vs Maitland Mobilization

SNAGs produced greater improvements in:
✔ Neck rotation
✔ Pain intensity
PubMed: PMID: 28882760

3. NAG + SNAG for Chronic Neck Pain

Combining NAG and SNAG significantly improved:
✔ Pain (VAS)
✔ ROM
✔ Neck Disability Index
PubMed: PMID: 30113428

4. Lumbar SNAGs for Chronic Low Back Pain

SNAGs improved:
✔ Oswestry Disability Index
✔ Lumbar flexion
✔ Pain on movement
PubMed: PMID: 27110787

5. SNAGs Improve Functional Movement

Randomized trial shows SNAGs enhance:
✔ Segmental mobility
✔ Pain-free active ROM
PubMed: PMID: 25829359

Benefits of NAG and SNAG for Patients

  • Immediate pain relief

  • Improved cervical and lumbar ROM

  • Better posture and spinal alignment

  • Faster functional recovery

  • Safe, non-invasive, and evidence-based

  • Useful in acute, subacute, and chronic phases

Conclusion

NAG and SNAG techniques are powerful components of the Mulligan Concept, offering immediate and long-term improvements in spinal mobility, pain, and function. Their combination of manual glide with active patient movement makes them highly effective for conditions like cervical stiffness, low back pain, and cervicogenic headaches.

With growing research support and consistent clinical results, NAG and SNAG techniques remain valuable tools for physiotherapists and manual therapy practitioners worldwide.


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