Squatting with a barbell, a Notch sensor strapped to the thigh and another to the upper arm

Learn from every rep you do

with 4 sensors on your body, from your first squat to your heaviest deadlift

Your own weight or any equipment
dumbbells, barbells, machines
Watch the rep back
3D replay of every set
Backed by research
80+ published studies

As seen on

Forbes, Smithsonian, TechCrunch, Digital Trends, Wired, Ars Technica, Yahoo

From a single rep to months of training

Seen from below against the sky, a man lifting a heavy dumbbell from behind his head with both hands, a sensor strapped to his left upper arm
The 3D replay of a rep, with the weight, the target reps and the reps counted so far

See your form from the outside

Watch the rep back in 3D and see where depth, setup or lockout slipped

A braided woman midway through a dumbbell Romanian deadlift at home, seen close from behind, sensors on her upper arm and lower back
The set list logging itself: weight, reps, RPE and a score on each set

Leave the notebook at home

The sensors count your reps and start the next set when rest is over

Seen from above, a woman on an exercise mat reaching for the heavier of two dumbbells
Rep max table: the weight and the percentage of your max for 1 rep through to 6

Lift the right weight

Notch reads how fast the weight moves and picks the load for the next set

A curly-haired woman with a gym bag on her shoulder, walking past palm trees and smiling at her phone
Volume, strength and form scores, and the paragraph naming the squat, the deadlift and the drop in speed

Get a coach's note when you finish

What held up, what slipped and what to do next time, in one paragraph, read aloud if you like

A tattooed man midway through a weight-plate halo in a gym, with a sensor strapped to his upper arm
Overall progress by week, with volume, weight, range of motion and speed under the chart

Watch your records add up

Personal records, the load on each muscle group and how your lifts move, week by week

A woman moving into a half-kneeling lunge at home, with sensors on her arm and thigh
A 12-week program in 4 blocks, with the week's days and their exercise counts

Follow a program built in blocks

12 weeks in 4 blocks, hypertrophy to strength, each day listed with its exercises and minutes

A woman resting on a red running track after a set, sensors on her upper arm and chest
Set scores falling from 95 to 55 as the bar slows, and the app calling it severe fatigue

Know when the set is done

Rep speed drops before you feel tired, and the app shows by how much

Each NotchThe Notch sensor holds a cluster
of motion A Notch sensor opened up: board, battery and housingsensors. They take
150+ measurements of each lift
and fold them into 4 numbers
that tell you what to change

  • Range of motion

    How far you actually moved, reported as a percentage of the full range

  • Bar speed

    How fast the weight moved, in meters per second, and it drops before you feel tired

  • Time under tension

    How long the muscle was actually working, counted across the whole set

  • Rep score

    150+ measurements folded into a single answer: was that a good rep or not

A hand pressing the strap snug on the upper arm, the sensor on the outside

Train the way you already do

Put the sensors on. 4 sensors go on the upper arm, the thigh, the chest and the back of the hip. The straps are mesh, and the chest sensor sits in the t-shirt.

  1. 4 sensors go on the upper arm, the thigh, the chest and the back of the hip. The straps are mesh, and the chest sensor sits in the t-shirt.

A few months in, three things change

  • Lift heavier

    The next weight comes from how fast the last set moved, so the load rises the moment you are ready.

  • Catch the rep that hurts

    Form is checked every rep, and a slowing bar is caught before the rep that costs a back or an elbow.

  • Make good form a habit

    The same correction on every rep until the good rep is the one you do without thinking.

Notch is built on nine years of research with labs and clinics

A hand holding the Notch sensor against the light
80+

peer-reviewed papers in biomechanics and healthcare

150+

motion parameters read on a single rep, every rep

3

patents pending, with 3 more now in the pipeline

4k+

Notch kits at work in clinics, labs and companies

3

generations of the sensor with the shape unchanged

10k+

recorded reps that taught the app each exercise

Published in

  • Stepan Boltalin

    Stepan Boltalin

    Co-founder and CEO. Developer and producer, NYU

  • Eszter Ozsvald

    Eszter Ozsvald

    Co-founder and CTO. Biorobotics and industrial engineer, NYU and BME

Everything in the Kit laid out: charging station, 4 sensors, straps, t-shirt, pouch and cable

The Notch Kit

Comes with your first year of the app

$400/ first year

About $1.10 a day. Shipping is free.

  • 4 Notch sensors upper arm, thigh, chest and the back of the hip
  • Breathable mesh straps for the arm, the thigh and the hip, washable
  • Sensor t-shirt holds the chest sensor through the fabric
  • Fast charging station charges all 4 at once, USB cord included
  • Carrying pouch takes the sensors and the straps together
  • 1 year of the app scores, feedback, replay and full history

After the first year the app continues on a yearly or monthly plan.

Free to join, no card needed. How we use your email

Used by

Mount Sinai, Zimmer Biomet, Stryker, John Deere, Vodafone, Lockheed Martin, Ars Technica