Mobility
Flexibility Score Calculator
Rate your sit-and-reach score against the Canadian (CPAFLA) norms for your age and sex, with an approximate percentile and how far you are from Very good.
Result
4 cm past your toes. Around the middle for your age. 10 minutes of stretching most days typically adds a few centimetres within 4 to 8 weeks.
Where you sit in your age group
The CPAFLA categories, each about a fifth of people your age and sex.
How to use it
- Do the sit-and-reach on the CPAFLA box scale: feet flat against the box at the 26 cm (about 10¼ in) mark, legs straight, reach forward slowly with both hands and take the best of two. With a ruler at home, add 26 cm to how far past your toes you reach, or subtract if you fall short. Test at the same time of day after the same brief warm-up each time.
- Enter the score, your age and sex. The rating comes from the CPAFLA norms for your age group and sex, so a 45-year-old rated Good is doing as well for their age as a 20-year-old rated Good.
- Below-average scores for your age indicate posterior chain tightness (hamstrings, hip flexors, lower back) — a significant risk factor for lower back pain and compensatory movement patterns.
- Evidence-based flexibility improvement: 30-second static stretches, 4+ times per week, produces measurable range-of-motion gains within 4–8 weeks. Dynamic warm-up before training is more effective than static stretching for pre-workout preparation.
- Flexibility gains reverse quickly — 2–3 weeks without stretching can undo 4 weeks of gains. Maintenance requires 1–2 dedicated flexibility sessions per week indefinitely.
Questions people usually ask
What is a sit-and-reach test?
A sit-and-reach test measures hamstring and lower-back flexibility. You sit with legs straight and feet against a box and reach forward as far as possible. On the CPAFLA box scale this tool uses, the feet sit at the 26 cm mark, so the score is 26 plus how far past your toes you reach.
Why can my score be negative?
On the box scale it is not: falling short of your toes gives a score below 26 cm, not below zero. If you measure from your toes with a ruler, a negative number just means you fell short; add 26 to it to get the box score, so 8 cm short scores 18.
How accurate is this flexibility assessment?
The ratings use the Canadian (CPAFLA, CSEP 2003) sit-and-reach norms by age and sex, and the percentile is interpolated within those categories, so it is an approximation. Warm-up, technique and body proportions move a score by a few centimetres.
How long does it take to improve flexibility?
Most people see measurable flexibility gains within 4–8 weeks of consistent daily stretching. Dynamic warm-up and static cool-down stretching work best together.
Is this tool free and private?
Yes. AI Fit Hub tools are free, browser-based, and no-signup. Your inputs stay in your browser.
Does this replace medical or fitness assessment?
No. This is a general estimate based on population norms — not a medical assessment. Consult a physiotherapist for a full flexibility evaluation.
The formula, worked through
- Formula Flexibility Score Formula
Flexibility score: Beighton hypermobility (0-9) + FMS Deep Squat (0-3). Beighton ≥5 suggests hypermobility; FMS ≤2 flags movement dysfunction.
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Background on the Flexibility Score Calculator
- Guide How to Improve Mobility for Better Lifts
How to improve mobility for bigger lifts. Targeted drills and corrective work to expand range of motion, prevent injury, and add kilos to squat and press.
- Comparison Foam Rolling vs Stretching for Recovery
Foam rolling vs stretching for recovery: foam rolling targets myofascial release, stretching extends muscle length. Direct side-by-side with citations.
- Examples Flexibility Score Examples
Discover real-world scenarios illustrating how flexibility scores impact recovery, performance, and daily life. Learn non-obvious insights on improving.
- Checklist Daily Mobility Routine Checklist
Build better movement with this daily mobility routine checklist. Improve flexibility, reduce stiffness, and enhance overall joint health in just minutes.
- Statistics Flexibility Statistics: Norms, Methods & Effects
Evidence-based flexibility statistics: range-of-motion norms, stretching method comparisons, age-related changes, and performance-injury implications.
- Learn What Is Mobility? Simply Explained
Discover the true meaning of mobility in fitness. Learn how active joint control and strength enhance movement, prevent injury, and boost performance.
Articles
- 10 min read Mobility Assessment: How to Test and Improve It
What mobility tests like sit-and-reach and the Functional Movement Screen actually measure, plus the stretching dose-response and a 6-week ROM protocol.
By goal
Use it from code
The same calculation as a JavaScript module you can import. It runs where you import it, with no request, key or rate limit.
import { compute } from "https://aifithub.io/engines/flexibility-score-calculator.js";Input and output contract, TypeScript types and the guide for agents.