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.
Formula
Copy the exact expression or work through it step by step below.
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
2
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
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Sources & References
- Beighton, Solomon & Soskolne (1973). Articular mobility in an African population. — Annals of the Rheumatic Diseases — foundational Beighton score paper
- Cook & Burton (2010). 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