Balance tells you what's coming.

Know where
you stand.

Balance is a leading indicator. It declines measurably, predictably, and trackably long before it produces consequences. Most people never measure it. Stela makes it possible to.

8balance tests
5 minper full session
0equipment needed
Session Results
BalanceAge™
48
Chronological age: 53
↑ 5 yrs younger
Bipedal EO
87
Narrow EC
68
Semi tandem EC
62
Head turn
74
Dual task
55
iOS — Health & Fitness
No equipment required
Peer-reviewed metric class · ICC 0.62–0.97
BalanceAge™

Balance,
expressed in years.

Like VO₂ max or bone density age, BalanceAge™ translates your results into years — the age at which a typical person balances exactly the way you do.

Two people. Both 52. Different balance age.
Person A41
Person B64
Actual age52
Same age. Meaningfully different balance. Stela tells you which one you are — and gives you a number you can actually track and act on.

Your balance system is aging. The question is how fast.

Your balance age compares your results across all 8 tests against how people your age and sex typically perform. The result is a single number that places your balance system on a biological timeline.

It stabilizes after 3 sessions and updates with each new assessment, so you can track whether your training, your habits, or the passage of time is moving it in the right direction.

Like VO₂ max age Like bone density age BalanceAge™ Like grip strength age

How it works

Your phone is already
a measurement device.

The accelerometer and gyroscope in a modern smartphone sample motion at 60–100 Hz. Sufficient to detect the postural micro-corrections that define balance stability. No wearables. No force plates. No appointment.

1

Position your phone

Hold your phone flat with one or both hands, arms comfortably against body. Screen faces up. No calibration required.

2

Complete the 8-test battery

Eight stances, 20–30 seconds each. Each isolates a different subsystem: vestibular, proprioceptive, visual, reactive, and cognitive-motor. The app guides you through every position.

3

See your BalanceAge™

After each stance, you get a score from 0 to 100 showing how you performed at that position. When all 8 are done, your balance age computes, a single number telling you where your balance system sits relative to people your age.


The 8-test battery

Every subsystem,
measured individually.

Your balance age gives you the headline number. The per-test scores — 0 to 100 for each stance — tell you exactly where your balance system is strong and where it needs work.

Standing — Eyes Open

Your baseline. Feet shoulder-width apart, eyes open. Establishes how much your balance depends on vision.

Visual system

Standing — Eyes Closed

Same stance, eyes closed. Without visual input, your inner ear and body position sensing carry the full load. The gap between this score and the previous one is diagnostically meaningful.

Inner ear · Body position

Narrow Stance — Eyes Closed

Feet together, eyes closed. A narrower base makes your body's position sensing work harder — the closest you can get to a balance challenge without any equipment.

Body position

Head Turn — Reactive

Rhythmic head rotation on cue. Measures how well your inner ear and vision coordinate to keep you stable while moving.

Inner ear · Reactive

Unexpected — Eyes Closed

Feet shoulder-width apart, eyes open. At an unexpected moment, an audio cue prompts you to close your eyes. Measures reactive postural control.

Reactive balance

Forward Head Posture

Head pitched 30° forward. Measures how neck position affects your overall balance — relevant to anyone who spends time at a desk or screen.

Neck · Dynamic

Dual Task — Arithmetic

Serial subtraction while standing. Measures how cognitive effort affects your stability — a well-established signal of fall risk.

Dual-task · Cognitive

Dual Task — Verbal Fluency

Category word naming while standing. A second cognitive challenge that cross-checks the arithmetic result — two different types of thinking, same question about stability.

Dual-task · Cognitive
The science

Balance doesn't just decline.
It accelerates.

Most health measurement is retrospective, a record of what already happened. Balance is different. It declines measurably years before consequences appear, and at predictable inflection points where the rate of change shifts sharply. Most people have no measurement of where they sit at any of them.

~40

First inflection

Muscle mass and proprioceptive sensitivity begin declining. Gradual, easy to miss — and the highest-leverage window for prevention.

~60

Acceleration

Inner ear function declines and reflexes slow, compounding the losses that began at 40. Fall risk begins rising steeply.

~75

Critical zone

Steep decline. Falls become the leading cause of injury-related mortality. Intervention shifts from performance to fall prevention.

4–6×
Elevated fall risk for adults in the bottom 10th percentile of their age cohort. Most people in that group have no measurement of it. Stela tells you exactly where you stand.
Features

The full battery.
Always free.

All 8 tests and trend tracking are free. Clinical deployment, with per-test percentile ranks, raw sway data, and multi-patient management is available to organizations via provisioning.

Clinical
Org / provisioned

For physical therapists, coordinators, and research teams.

  • Per-test percentile ranks (1–99)
  • Raw sway velocity (m/s³)
  • Multi-subject profile management
  • PDF export for clinical records
  • Coordinator sleeve placement protocol
  • Group overview and aggregate trends
  • Audit log

Privacy & data

Stated
plainly.

Your account details are stored securely and never shared. Session data syncs to encrypted cloud infrastructure for backup and cross-device access. Your anonymized sway measurements contribute to the population normative dataset that makes it meaningful. A longitudinal dataset that does not currently exist at this scale.

Account details stay private

Your name, date of birth, and account information are stored securely. They are never shared with third parties, sold to advertisers, or used for purposes other than your account.

Session data: encrypted, not sold

Sessions sync to encrypted, HIPAA-compliant cloud infrastructure. Your anonymized sway measurements contribute to the population normative dataset. They are never sold or licensed to third parties.


FAQ

Questions worth
answering directly.

No. Stela is a measurement and tracking tool, not a diagnostic instrument. It gives you longitudinal data about your postural stability — data worth taking to a clinician. If you have a known fall history, vestibular disorder, or neurological condition, consult a clinician before using Stela unsupervised.
Each test produces a movement measurement. That value is compared against how people your age and sex typically perform on that stance. Your balance age for each test is computed independently, then combined into a single number. The displayed value is a rolling median of your last 3 complete sessions, which smooths out natural day-to-day variation.
The test battery runs fully offline — scoring and session storage happen on your device. An internet connection is required to sync your results and contribute to the population dataset. If you're offline, sessions queue locally and sync when connectivity is restored.
Your balance age stabilizes after 3 sessions. If you're monitoring the impact of a training program, monthly sessions are typically sufficient to detect meaningful shifts. Once a week gives you enough data if you are working with a clinician.
Your personal details are stored securely on your account and never shared with third parties. Your anonymized sway measurements contribute to the population normative dataset that powers BalanceAge™.
Yes, with our clinical tier. The clinical version includes per-test percentile ranks, raw sway velocity, PDF export, audit logging, and multi-patient management built on HIPAA-aligned AWS infrastructure. Contact us to discuss clinical or research deployment.
Apple Health integration is on the roadmap. The current version stores all data locally within the app. When HealthKit integration ships it will be optional — Stela will not read from or write to Apple Health without an explicit permission grant from you.
Know your BalanceAge™

Your BalanceAge™ is a
number worth knowing.

Five minutes. Your phone. No equipment. Free. Most people never measure this. Stela makes it possible.