For the curious & the clinical

The research behind
the number.

Poise turns your posture into a single score. That number isn't a guess — it's built on peer-reviewed biomechanics and the assessment tools physiotherapists use every day. Here's the thinking, in plain language, with every paper listed at the bottom.

  1. 01

    Your head is a weight on a lever.

    An adult head weighs roughly 4–5 kg. When you hold it upright, it sits balanced over your spine and your neck barely has to work. Tip it forward to look down, and that same weight swings out in front of you — so the muscles at the back of your neck have to pull harder to stop it dropping. Researchers who measured this found the demand on your neck grows to several times its resting level at the angles people naturally hold a laptop or phone. That extra effort, repeated all day, is exactly what Poise is scoring.

    Vasavada et al. 2015 · Straker et al. 2009 · Yoganandan et al. 2009

  2. 02

    We rejected the "27 kg head" myth.

    You've probably seen the viral claim that looking at your phone puts "27 kg" of force on your neck. It comes from a single 2014 note that was never properly peer-reviewed and included no real measurements — and researchers in the field have pushed back on the whole "text neck" panic it started. The direction is real: leaning forward does load your neck more. But the scary number is not. Poise is built on the studies that actually measured things, not the headline.

    Hansraj 2014 (rejected) · Meziat-Filho 2018 · Grasser et al. 2023 · Damasceno et al. 2018 · Correia et al. 2021

  3. 03

    Normal movement isn't a problem.

    Your neck is meant to move. Small, everyday shifts — glancing down, tilting to read — are completely normal and shouldn't count against you. The ergonomic checklists physiotherapists use to assess posture agree: they treat a band of gentle movement near upright as neutral, and lab studies of the spine confirm there's a genuine low-effort zone there. So Poise ignores the small stuff and only starts adding to your score once you're genuinely leaning — which is why it doesn't nag you for being alive.

    RULA — McAtamney & Corlett 1993 · REBA — Hignett & McAtamney 2000 · Wilke et al. 2025

  4. 04

    What matters is how far, times how long.

    A quick glance down is harmless. The same posture held for an hour is not. Occupational-health research consistently finds it's the combination — how awkward the posture is, multiplied by how long you stay in it — that adds up over a working day. That's why a single "you're slouching" alarm misses the point, and why a running total that reflects both how far you lean and how long you hold it is a far more honest picture of your day.

    Ariëns et al. 2001 · occupational exposure–response literature

  5. 05

    Recovery is real — so the score recovers too.

    Give tired neck muscles a rest and they recover over a matter of minutes. Poise reflects that: alongside your all-day total, a live reading rises while you're hunched and eases back down when you sit tall. It means good posture is actually rewarded in the moment, and a gentle reminder only ever appears after you've genuinely been leaning for a while — never for a passing glance.

    Kramer et al. 2007 · Lee et al. 2015

  6. 06

    What we refuse to ship.

    Plenty of apps borrow a fitness-world "injury risk" formula and slap it on your data. We looked hard at that formula and left it out — even in the sports science it came from, it's been widely criticised as unreliable, and it's never been validated for posture at all. We'd rather show you one number we can stand behind than a scary risk score we can't. Being honest about the limits is part of the product.

    Gabbett 2016 (origin) · Lolli et al. 2019 · Impellizzeri et al. 2020 · Wang et al. 2020

THE SHORT VERSION

Leaning forward loads your neck, and it's the dose over a whole day — not any single moment — that counts. Poise measures that dose honestly, ignores normal movement, rewards recovery, and refuses to invent risks the science can't support.

The papers

Full references.

Every source behind the reasoning above. Peer-reviewed unless otherwise noted.

  1. Ariëns GAM, Bongers PM, Douwes M, et al. (2001). Are neck flexion, neck rotation, and sitting at work risk factors for neck pain? Occupational and Environmental Medicine 58(3):200–207.
  2. Correia IMT, Ferreira AS, Fernandez J, et al. (2021). Association Between Text Neck and Neck Pain in Adults. Spine 46(9):571–578.
  3. Damasceno GM, Ferreira AS, Nogueira LAC, et al. (2018). Text neck and neck pain in 18–21-year-old young adults. European Spine Journal 27:1249–1254.
  4. Gabbett TJ (2016). The training–injury prevention paradox: should athletes be training smarter and harder? British Journal of Sports Medicine 50:273–280.
  5. Grasser T, Borges Dario A, Parreira PCS, Correia IMT, Meziat-Filho N (2023). Defining text neck: a scoping review. European Spine Journal 32(10):3463–3484.
  6. Hansraj KK (2014). Assessment of Stresses in the Cervical Spine Caused by Posture and Position of the Head. Surgical Technology International 25:277–279. Not peer-reviewed to Q1/Q2 standard; single-author model with no methods or measured data — cited here only as the source of the "27 kg" claim we reject.
  7. Hignett S, McAtamney L (2000). Rapid Entire Body Assessment (REBA). Applied Ergonomics 31:201–205.
  8. Impellizzeri FM, Woodcock S, Coutts AJ, et al. (2020). What Role Do Chronic Workloads Play in the Acute:Chronic Workload Ratio? Sports Medicine 50:1613–1618.
  9. Kramer M, Ebert-Durret V, et al. (2007). Electromyogram and perceived fatigue changes in the trapezius muscle during typewriting and recovery. European Journal of Applied Physiology 100(1):89–96.
  10. Lee S, Lee D, Park J (2015). Effect of the cervical flexion angle during smartphone use on muscle fatigue of the cervical erector spinae and upper trapezius. Journal of Physical Therapy Science 27(6):1847–1849.
  11. Lolli L, Batterham AM, Hawkins R, et al. (2019). Mathematical coupling causes spurious correlation within the conventional acute-to-chronic workload ratio. British Journal of Sports Medicine 53:921–922; 53:1510–1512.
  12. McAtamney L, Corlett EN (1993). RULA: a survey method for the investigation of work-related upper limb disorders. Applied Ergonomics 24(2):91–99.
  13. Meziat-Filho N, Ferreira AS, Nogueira LAC, Reis FJJ (2018). "Text-neck": an epidemic of the modern era of cell phones? The Spine Journal 18(3):714–715.
  14. Mousavi-Khatir R, Talebian S, Toosizadeh N, et al. (2018). The effect of static neck flexion on mechanical and neuromuscular behaviors of the cervical spine. Journal of Biomechanics 72:152–158.
  15. Straker LM, Skoss R, Burnett AF, Burgess-Limerick R (2009). Effect of visual display height on modelled upper and lower cervical gravitational moment, muscle capacity and relative strain. Ergonomics 52(2):204–221.
  16. Tapanya W, Puntumetakul R, Neubert MS, Boucaut R (2021). Influence of neck flexion angle on gravitational moment and neck muscle activity when using a smartphone while standing. Ergonomics 64(7):900–911.
  17. Vasavada AN, Nevins DD, Monda SM, Hughes E, Lin DC (2015). Gravitational demand on the neck musculature during tablet computer use. Ergonomics 58(6):990–1004.
  18. Wang C, Vargas JT, Stokes T, Steele R, Shrier I (2020). Analyzing Activity and Injury: A Review of the Acute:Chronic Workload Ratio. Sports Medicine – Open 6:45.
  19. Wilke HJ, et al. (2025). Range of Motion and Neutral Zone of All Human Spinal Motion Segments. JOR Spine.
  20. Yoganandan N, Pintar FA, Zhang J, Baisden JL (2009). Physical properties of the human head: mass, center of gravity and moment of inertia. Journal of Biomechanics 42(9):1177–1192.

Poise is a consumer measurement tool, not a medical device or a diagnosis.

Honest by design.
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