Formula, in mobility

Flexibility Score Formula

Flexibility assessment combines two validated screens: the Beighton hypermobility score (9-point joint laxity test) and a FMS Deep Squat score (3-point movement quality). High Beighton scores (≥5) indicate connective-tissue laxity associated with EDS or BJHS; low FMS scores (≤1) indicate movement dysfunction at the squat pattern. Together they distinguish 'mobile but stable' from 'mobile but unstable' — the second carries injury risk that targeted mobility work won't fix.

6 variables. Published May 14, 2026. By AI Fit Hub.

Education, not medical advice. The result comes only from the published formula and your inputs. How we check our formulas.

Formula

beighton_score = thumb_R + thumb_L + pinky_R + pinky_L
                  + elbow_R + elbow_L + knee_R + knee_L
                  + spine_forward_fold
   each scored 0 or 1 (max 9)

FMS_deep_squat = {0, 1, 2, 3} per FMS rubric
   3 = perfect form, 2 = compensation, 1 = partial range, 0 = pain

flexibility_class:
   Beighton ≥5: hypermobile (refer if symptomatic)
   Beighton ≤2 AND FMS ≤1: stiff + dysfunctional → targeted mobility
   Beighton 3-4 AND FMS 2-3: normal range
   Beighton ≥5 AND FMS ≤1: hypermobile but uncontrolled → stability work, not stretching

Variables

thumb_R/L

Passive thumb-to-forearm

Can passively flex the thumb to touch the volar forearm. Score 1 if it touches, 0 if not. Per side.

pinky_R/L

Pinky hyperextension >90°

Passively bend pinky finger backward past 90° at the MCP joint. Score 1 per side if achieved.

elbow_R/L

Elbow hyperextension >10°

Elbow extends past 180° (negative angle) by 10° or more. Score 1 per side if achieved.

knee_R/L

Knee hyperextension >10°

Standing or supine, knee extends backward past 180° by 10° or more. Score 1 per side if achieved.

spine_forward_fold

Palms flat on floor in forward fold

Knees straight, palms flat on floor with bent forward — score 1 if achieved, 0 if not.

FMS_deep_squat

FMS Deep Squat score

Functional Movement Screen deep squat: 3 = perfect form (upper body parallel to tibia, arms overhead, thighs below horizontal, knees over feet); 2 = same with heels elevated; 1 = cannot achieve even elevated; 0 = pain during attempt.

Step by step

1

Perform the 9 Beighton tests (4 paired + 1 single). Score 0 or 1 each.

Thumb R 1, Thumb L 1, Pinky R 1, Pinky L 1, Elbow R 0, Elbow L 0, Knee R 1, Knee L 1, Forward fold 1 = Beighton 7.
2

Perform FMS Deep Squat: stand, hold dowel overhead with elbows extended, squat to depth.

Heels stay flat, thighs reach parallel, arms remain overhead, slight knee valgus → FMS score 2.
3

Classify based on combined score.

Beighton 7 + FMS 2 = hypermobile but functionally adequate. Continue normal training, monitor for joint instability symptoms.
4

Translate to training prescription.

Hypermobile (≥5): emphasize stability — controlled-tempo lifting, anti-extension core work, avoid loaded end-ROM (deep yoga, ballistic stretching). Stiff + low FMS: targeted mobility before strength — hip mobility, T-spine extension, ankle dorsiflexion.
5

Refer if Beighton ≥5 + symptoms (chronic joint pain, frequent dislocations, fatigue) — possible BJHS / hEDS. Beighton alone is screening, not diagnostic.

Patient: Beighton 7, recurrent shoulder subluxation, joint pain — refer to rheumatology for EDS workup.

Worked example

30-year-old recreational lifter wonders why mobility work doesn't improve their squat depth

Beighton tests

Thumbs 2, Pinkies 0, Elbows 0, Knees 0, Forward fold 0

Beighton total

FMS Deep Squat

1 (cannot reach parallel even with heel lift)

Beighton 2 (low-normal) + FMS 1 (poor) Classification: stiff + dysfunctional

This profile indicates true mobility restriction, not just weakness. Targeted intervention: ankle dorsiflexion (banded mobilization, calf eccentric work 4×/week), hip mobility (90/90 rotations, deep squat hold), T-spine extension (foam roll, prone Y-T-W raises). Re-test FMS at 6 weeks. If still ≤1, consider PT referral. Heavy back-squat training contraindicated until pattern improves.

Common variations

Modified Beighton: some research adds shoulder-internal-rotation + ankle-dorsiflexion tests (11-point). The original 9-point remains the most validated in EDS/BJHS literature.

Brighton 1998 criteria: combines Beighton ≥4 with joint symptoms to clinically diagnose BJHS. Beighton alone is sensitivity, not specificity.

FMS complete: 7 movement screens (deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability push-up, rotary stability). Composite 0-21. Cook & Burton 2010 cited threshold ≤14 as elevated injury risk.

Sit-and-reach test: alternative to Beighton + FMS for general flexibility. Less informative because doesn't distinguish hip from hamstring from spine flexibility.

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Questions people ask next

What is the Beighton score and how is it calculated?

The Beighton score is a 9-point joint-laxity test for hypermobility. You score 1 point per side (left and right) for four paired maneuvers: passively touching the thumb to the forearm, bending the pinky past 90 degrees, hyperextending the elbow past 10 degrees, and hyperextending the knee past 10 degrees. The 9th point is for placing both palms flat on the floor in a standing forward fold with straight knees. The maximum is 9.

What Beighton score counts as hypermobile?

A Beighton score of 5 or higher suggests joint hypermobility (connective-tissue laxity associated with conditions like EDS or BJHS). A score of 3-4 is treated as normal range on this page, and 2 or below is low-normal or stiff. Beighton is a screen, not a diagnosis, so a high score with symptoms such as chronic joint pain or frequent dislocations warrants a referral rather than self-diagnosis.

How does the flexibility score combine Beighton with the deep squat?

The page pairs the Beighton hypermobility score with the FMS Deep Squat score (0-3, where 3 is perfect form and 0 is pain). Together they separate 'mobile but stable' from 'mobile but unstable': a high Beighton with a low squat score (5 or more plus FMS 1 or less) signals hypermobile-but-uncontrolled, which calls for stability work rather than more stretching, while a low Beighton plus a low squat score points to true stiffness that needs targeted mobility.

What is the difference between the Beighton score and a hypermobility diagnosis?

The Beighton score is a screening tool that measures sensitivity to joint laxity, not a clinical diagnosis. The Brighton 1998 criteria combine a Beighton of 4 or more with joint symptoms to clinically diagnose benign joint hypermobility syndrome. So a high Beighton alone flags who to look at more closely; diagnosis requires the symptom criteria and, where indicated, a specialist workup.

If I am hypermobile, should I stretch more?

No. For a hypermobile profile (Beighton 5 or higher), the page recommends emphasizing stability over stretching: controlled-tempo lifting, anti-extension core work, and avoiding loaded end-range positions like deep yoga or ballistic stretching. Added mobility work does not fix instability and can increase joint risk. Targeted stretching is for the stiff, low-squat-score profile instead.

Sources

Beighton, Solomon & Soskolne (1973). Articular mobility in an African population. , Annals of the Rheumatic Diseases — foundational Beighton score paper
Teyhen et al. (2012). The Functional Movement Screen: A Reliability Study. , JOSPT — FMS validity + reliability
Beighton, Grahame & Bird (2012). Hypermobility of joints (4th ed.). , Springer — clinical reference for hypermobility assessment
Malfait et al. (2017). The 2017 international classification of the Ehlers-Danlos syndromes. , American Journal of Medical Genetics — modern EDS classification