Accel-Decel-Re-accel (ADR) Test

Why it matters

Go, stop, go again. VueMotion measures every phase.

Every ADR run gives you three phases, each with its own metrics.

ACC

Acceleration

Acceleration, speed at 10 m, first six stride lengths relative to height, step frequency and flight time.

DEC

Deceleration

Distance from top speed to zero, deceleration, contact times, step length and touchdown distance to the centre of mass.

Re-acceleration

Acceleration, top speed, step length, frequency, contact and flight time after the step back.

Performance monitoring

Are all three phases improving?

Phase by phase Acceleration, deceleration and re-acceleration metrics vs baseline.
Speed at 10 m Shows whether the athlete is reaching top speed before braking.
Trend Re-test every few weeks.

Performance improvement

Is speed lost in the stop or the restart?

Deceleration Long stopping distances point to braking capacity or technique.
Re-acceleration Slow re-acceleration points to poor force production from a stop.
Kinematics Trunk, hip, knee, ankle angles and foot strike show how each phase is produced.

Injury risk reduction

Who struggles to control repeated braking?

Braking mechanics Large touchdown distances and stiff knees concentrate load.
Swing leg Swing-leg angular velocity shows how the leg recovers between contacts.
Foot strike Full, mid or rear foot strike in each phase.

Safer, faster return to play

Can the athlete stop and go again with confidence?

Progression Add ADR after straight-line speed and ADA are back to baseline.
Baseline Compare each phase with pre-injury results.
Quality Check braking and restart mechanics, not just times.

Benchmarking

How does the athlete compare?

Normative range Each phase against sport and cohort.
Profiles Group athletes by where they lose speed.
Squad view Set standards by position.

Scouting & talent ID

Who changes pace best?

Objective Calibrated metrics from one iPhone.
Repeatable speed Strong re-acceleration marks game-ready athletes.
Complete Speed, braking and restart in one test.

These metrics describe movement patterns linked to performance and injury risk in research. They support coaching and clinical judgement; they do not diagnose or predict an individual injury.

01 · Setup

The 20 m lane and camera

Use the standard 20 m, 5-cone lane (as for the 20 m Acceleration and Fly tests), 1.22 m wide. Braking starts after the 10 m cone.

ConesSide camera viewFront camera view (optional)Decel zone

Sagittal camera

On a tripod, perpendicular to the lane at the 10 m cone, about 19 m back (as for the 20 m Acceleration test). Landscape, 1× lens, whole lane in frame.

Front camera (optional add-on)

About 5 m beyond the nearest exit (end) cones, in line with the lane and facing the athlete, at the same height as the sagittal camera (1.5 m), portrait, 3× zoom on the athlete. Record both phones in sync with Controller-Capture. The front view adds coronal (frontal-plane) angles at the synchronised touchdown and toe-off events, such as knee alignment (FPPA), pelvic drop, trunk side lean and step width. Safety first: the athlete must be able to slow down well before reaching the camera; move it further back if needed.

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The step back

After stopping, the athlete takes one step backwards, then re-accelerates forwards through the 20 m cones.

Camera distance follows the 20 m lane setup. iPhone 11 or newer.

02 · Capture

Record in about five minutes

Equipment

1 or 2 iPhones, tripods, five 9-inch cones and a measuring tape.

Lane

Lay out the 20 m, 5-cone lane, 1.22 m wide.

Cameras

Side camera ≈ 19 m back at the 10 m cone; optional front camera ≈ 5 m past the end cones (portrait, 3×, Controller-Capture).

Tag + record

Choose the athlete and the ADR test tag, then record.

Upload

Upload the original files and submit the AI request.

Athlete

Warm up, finishing with build-up runs and a few practice efforts
Accelerate to the highest speed possible by 10 m
After the 10 m cone (not before), stop as quickly as possible
Take one step back, then re-accelerate past the 20 m cones

Camera settings

4K at 60 fps on iPhone (or 4K 120 fps on GoPro)
Auto-FPS off (Settings → Camera → Record Video)
Side camera: landscape, 1× lens; front camera: portrait, 3× zoom, same height (1.5 m)
Do Not Disturb on, Auto-Lock never

Scene & upload tips

Start recording before the athlete moves; stop after they have stopped or crossed the last line
Other athletes queue outside the camera's view
Runs can go in either direction; move the front camera to the finish end
Upload original files from the app; avoid AirDrop or messaging apps

03 · Outputs

What you get after upload

Acceleration

Acceleration, speed at 10 m, first six stride lengths (% of height), step frequency, flight time, horizontal centre-of-mass displacement.

Deceleration

Distance from top speed to zero, deceleration, final speed, contact time, step length and frequency, flight time, touchdown distance to centre of mass.

Re-acceleration

Acceleration, top speed, step length and frequency, contact and flight time, centre-of-mass displacement.

Kinematics

Trunk, hip, knee and ankle angles, swing-leg angular velocity and foot-strike type.

Speed curve

Speed through all three phases.

Front view (optional)

Coronal angles at synchronised touchdown and toe-off: knee alignment, pelvic drop, trunk side lean, step width.

CSV / API

CSV/Excel for Enterprise and Academy; API for Enterprise.

Linking acceleration, braking and restart to performance and injury

Metric	Link to performance or injury	Evidence

Performance linked to performance Prospective linked to future injury in a cohort study Mechanistic linked to tissue loading in lab studies Practice coaching rationale

Metric definitions

Acceleration

Acceleration (m/s²): Rate of speed gain to 10 m.
Speed at 10 m (m/s): Speed at the 10 m cone, close to braking onset.
Initial 6-stride length (% height): Average length of the first six strides relative to height.
Step frequency (steps/s), flight time (s): Rate of steps and time in the air between steps.
Horizontal CoM displacement (m): Forward movement of the centre of mass per step.

Deceleration

Distance from max speed to zero (m): How far the athlete travels while stopping.
Deceleration (m/s²): Rate of slowing down.
Final speed (m/s): Speed at the end of the braking phase.
GCT, step length, frequency, flight time: Step metrics during braking.
Touchdown to CoM distance (m): How far ahead of the centre of mass each foot lands.

Re-acceleration & kinematics

Acceleration, max speed: Speed gain after the step back.
Step metrics: Step length, frequency, contact and flight time.
Trunk, hip, knee, ankle angles: Joint angles through each phase.
Swing-leg angular velocity: How fast the swing leg moves from toe-off to touchdown.
Foot strike: Full, mid or rear foot contact.

04 · Practitioner value

Three phases, one test

Game-like

Mirrors the speed-up, stop and go-again pattern of field sports.

Find the weak phase

See whether speed is lost in the brake or the restart.

Rich kinematics

Joint angles, swing-leg speed and foot strike in each phase.

Standard lane

Uses the same 20 m setup as Acc and Fly.

Return to play

A final straight-line step before full multi-directional work.

One iPhone

No radar or timing gates needed.

05 · Support

FAQs

Is it a timed test?

Not mainly. The aim is to rise to speed and come down from it; the phase metrics matter more than the time to 20 m.

Why the step back?

It forces a full stop and a true restart from zero, like pressing and recovering in a game.

Do I need the front camera?

No. The side camera gives every metric; the front camera adds a second view.

Are CSV exports and APIs available?

CSV/Excel export for Enterprise and Academy users, and API access for Enterprise users.

Harper DJ, Carling C, Kiely J. High-intensity acceleration and deceleration demands in elite team sports competitive match play: a systematic review and meta-analysis of observational studies. Sports Medicine. 2019;49(12):1923–1947.
Harper DJ, McBurnie AJ, Dos'Santos T, et al. Biomechanical and neuromuscular performance requirements of horizontal deceleration: a review with implications for random intermittent multi-directional sports. Sports Medicine. 2022;52(10):2321–2354.
Harper DJ, Morin JB, Carling C, Kiely J. Measuring maximal horizontal deceleration ability using radar technology: reliability and sensitivity of kinematic and kinetic variables. Sports Biomechanics. 2023;22(9):1192–1208.
McBurnie AJ, Harper DJ, Jones PA, Dos'Santos T. Deceleration training in team sports: another potential 'vaccine' for sports-related injury? Sports Medicine. 2022;52(1):1–12.
Haugen T, Buchheit M. Sprint running performance monitoring: methodological and practical considerations. Sports Medicine. 2016;46(5):641–656.