Shoulder Flexibility (Zipper / Back-Scratch) Test
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Reach one hand over the shoulder and the other up the back to see if the fingers meet behind you; the gap (or overlap) indexes shoulder mobility and is scored as a distance.
Detail
The shoulder flexibility test — the "zipper test" (Apley scratch) and the back-scratch test (Senior Fitness Test version) — assesses combined shoulder flexion, extension, internal and external rotation, plus scapular mobility.
Protocol: reach one arm over the same-side shoulder and down the back (shoulder flexion + external rotation), and the other arm behind the back and up (extension + internal rotation), attempting to touch/overlap the fingers between the shoulder blades. Measure the distance between fingertips: overlap = positive, touching = 0, gap = negative (cm/in). Test both sides (the dominant/throwing side often differs). Take the best of 2 trials per side.
Interpretation: asymmetry between sides is informative (common in throwing athletes and after shoulder injury). The back-scratch variant has Senior Fitness Test norms by age/sex for older adults. It is a quick screen, not a substitute for goniometric ROM when precision is needed.
Key facts
- Assesses combined shoulder flexion/extension + internal/external rotation + scapular motion.
- One hand over the shoulder, the other up the back; score the fingertip gap/overlap (cm/in; overlap positive).
- Test both sides; note asymmetry; best of 2 trials/side.
- Senior Fitness Test back-scratch variant has age/sex norms for older adults.
Connections
- Sit-and-Reach Test (and Variants) — lower-body flexibility companion.
- Goniometry & Range-of-Motion Measurement — precise joint-angle alternative.
- Flexibility Test Norms & Interpretation — interpretation context.
- Shoulder / Arm Range of Motion — the joint ROM being assessed.
Sources
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Educational content only — not medical advice. Always consult a qualified professional for individualized guidance, especially around injury, pregnancy, or medical conditions.