Based on scientific discoveries

Train less. Get stronger. Recover.

Logic Workout recruits your muscles to near-maximal relative mechanical tension, induced by rolling, chaotic deformation and spring forces. Results show more strength than weight training, and users report their chronic pain resolved thanks to a well-balanced body.

All you need is the Logic ball and the app to follow the method.

Free for 14 days

Download on the App Store Get it on Google Play
A man doing push-ups with both hands on Logic balls, and a woman on all fours with one knee on a Logic ball

Read the science

The Logic Workout app

Test your strength

Logic Workout is humbling, making any weakness apparent.

When you know what to solve, you can train it. Start with the two tests that matter most: the Logic Standard, the bar for a body that holds up, and the Logic Athlete, for people who compete. Every result lands on one ladder and colours a body map, so the weak link has nowhere to hide.

You can also train for the NFL Combine events or the Army Fitness Test with Logic Workout exercises, and try to hit their published standards in the app.

Are you fit for it? The Army tests whether you're fit for the job. Do the same for what you love: tennis, surfing, skiing, running and more, each with its own test and the preparation workouts to close the gap. Tests are part of Premium. Free for 14 days.

Logic Standard & Logic Athlete · NFL Combine · Army Fitness Test · Logic Carryover

  1. Injury Risk
  2. Healthy
  3. Strong
  4. Athlete
  5. Legend
See the strength testsAre you fit for these activities?
Body maps in the Logic Workout app, in English and French, each muscle coloured by its strength band

The Logic Workout app

Train less

40-minute sessions are the maximum pros can endure.

Logic Workout is about 3 times more effective than weight training for building strength: 2h of Logic beats 6h of weights.

Workouts run from 10 to 40 minutes. Short on time? Do the 3-minute daily challenges. Activity preparation workouts get you ready for what you are about to do, whether that is skiing, surfing, running or a heavy lift.

A progressive library keeps scaling: the limiter shifts from balance to the prime movers as you get better, so the same exercise keeps working.

English and French.

The Today tab in the Logic Workout app, in English and in French: the weekly goal and the day's workout

What users say

26 ratings on the App Store

  • As an avid gym goer of 20 years this app was a humbling experience. I dove straight in with the hard levels and quickly realised I'd have to start from the entry level.

    Danjamespalner, App Store review

  • I was shocked to feel so many muscles I have NEVER felt before being pushed to the limit. When doing the squats, it felt as difficult as squatting a bunch of weight.

    MadeleineM14, App Store review

  • Great workout progressions, intelligently designed, straight forward and easy to follow, the use of the ball makes it so the muscles work a lot, but it's low stress on the body!!!

    E THE PT, App Store review

The equipment

The Logic ball, a special ball for maximum efficiency

Two 20–22 cm balls (8–8.7 in), non-slip, rated to 200 kg (440 lb), with a carrying bag. The rolling, deformation and spring rebound the method depends on come from the ball itself: small enough that corrections have to be fast, deformable enough that the surface never repeats.

Buy a set of two Logic balls
The Logic ball held up on a beach: grey, with the Logic Workout mark

Get stronger

Strength and muscle without heavy weights?

A heavy set takes you near failure in 5 reps, but only in a few prime movers. On the Logic ball, at the right level, 5 reps is just as hard, and the stabilizers work near failure too: dozens of muscles near their own limit at once, at low load.

Gym-goers and athletes who switched to Logic, or swapped 2 hours of their training for it, all added at least 15% to their PR lifts in one month, in weight or in reps. Olympic athletes included. Established with 1000+ people over 10 years.

Read the first study
A man in a pike with both feet on Logic balls, and a woman in a single-leg glute bridge with one foot on a Logic ball

The mechanism

The Reactive Falling Effect

The ball produces three forces at once, rolling, chaotic deformation, and a spring rebound, so your nervous system can never pre-load a motor pattern. The Logic ball is 18 to 22 cm: it rolls, deforms and springs back about ten times a second, close to human reaction time, so corrections have to be fast. A Swiss ball moves you less than once a second, and even a 30 cm ball gives 30 to 40% less reactive demand.

Accelerometry shows roughly ten times the jerk of a stable, maximally braced push-up, and 17 times the reactive demand of weight training. Reactive demand is our proxy for how many muscle fibers have to work, not a count of them. A university study, built for full peer review, will measure the recruitment directly.

Method: Apple Watch wrist accelerometer, 2–12 Hz band. Push-up: jerk and spectral power, against a stable push-up matched for voluntary tension. Weight training: jerk and Welch power spectral density, 3 axes, our measurements. A demand characterisation, not a recruitment measurement.

Push-up with both fists on a Logic ball
Rolling
Pressing a Logic ball into the ground
Deformation
Squeezing a Logic ball between the hands
Spring effect

The Logic Workout app

Recover

Pain is not normal.

People live with it, thinking it is normal or just age. It often comes from training too much or too little. Some muscle fibers atrophy, others hypertrophy, and the imbalance pulls on your ligaments. Your natural posture shifts, and chronic pain and weakness follow.

Logic Workout helps you recover. It makes the weak fibers work first. Your body rebalances, blood flow improves, and it has what it needs to repair. Unlike other physio and rehab methods, that is a long-term fix.

Users report their pain resolved even when they didn't come for it. In the recovery cohort of our first open-access preprint, peer review pending, participants reported their pain resolved and their strength and function regained.

Read the recovery cohort
The Recovery tab in the Logic Workout app: the Reduced Mobility Test, then recovery workouts by body area

World champions, gym-goers, young mothers, longevity seekers: all switching to Logic Workout

Training less, they report better results than years of their old programs.

  • Nathalie Moellhausen training with the Logic ball

    Olympic fencing

    Nathalie Moellhausen

    Cut her training from 10 hours a week to 3 and reported better performance: faster recovery, more time on fencing skill.

    Athlete-reported.

  • Soop training with the Logic ball

    Strength & mass

    Soop

    His physique fronted the Expendables poster. He added Logic Workout to push his strength and mass further, without ever touching a weight.

  • David training with the Logic ball

    Weightlifting

    David

    Added 25 pounds to his squat after years of plateau, on one hour of Logic a week.

    User-reported result.

  • Two photos of Didier. May 2023: the stapled scar on his shoulder after the operation. 2025: a push-up with one hand on a Logic ball, beside a pool

    Longevity

    Didier, 69

    Our co-founder. After a heavy shoulder and elbow operation and a physiotherapy plateau, he took up Logic Workout: 15 minutes every morning. He reports full range of movement, stronger than before, and he is back kitesurfing.

    User-reported result.

Why Logic is different

Measured, not guessed.

Apple Watch integration gives you a real-time Logic Effort Score, so you can see the effort a session actually demanded rather than guessing from how it felt. Stability and consistency are tracked alongside it, and every workout is logged against a weekly goal.

Logic was built by a physicist and an engineer, and it runs like a lab: a named mechanism, measured numbers, a result established with 1000+ people over 10 years, and a first study that confirmed it. Next, a university study built for full peer review. No number without its method.

The Logic Effort Score and session metrics in the app

  • 17×

    the reactive demand of weight training

    Our measurements, Pilates = 1×: Logic Workout 50×, weight training 3×. Wrist accelerometry (Apple Watch): jerk and Welch power spectral density, 3 axes, 2 to 12 Hz. Reactive demand is our proxy for how many muscle fibers have to work.

  • +15%

    minimum on PRs, in one month

    Gym-goers and athletes who switched to Logic, or swapped 2 hours of their training for it. All of them, in weight or in reps.

  • First

    study confirmed it

    Open-access preprint on arXiv (2506.13959), peer review pending. Next: a university study, built for full peer review.

  • 2 h

    a week. The whole program.

Logic vs other methods

6 ways to get strong. Compared.

Muscle grows from effort near failure. Weights take a few prime movers there in 5 reps. Unstable tools let you do lots of reps, so you rarely get there. On the Logic ball, at the right level, 5 reps take every muscle near failure.

#1 · Logic Workout

5 reps near failure. Every muscle.

What we found

Gym-goers and athletes who switched to Logic, or swapped 2 hours of their training for it, all added at least 15% to their PR lifts in one month, in weight or in reps. Olympic athletes included. Established with 1000+ people over 10 years. A first study confirmed it.

First study: Sornette & Sornette, 2025. Open-access preprint on arXiv (2506.13959), peer review pending.

What's next

A new study with a university, built for full peer review: independent confirmation, and exactly how it works. To take part or support it, contact us.

#2 · Weights

The reference for max strength.

What the research says

Heavy, stable, predictable. Ground-based free weights are what sports science recommends to build strength in athletes.

Canadian Society for Exercise Physiology, position stand (Behm et al., 2010)

The difference with Logic

A heavy set takes you near failure in 5 reps, but only in a few prime movers. On the Logic ball, at the right level, 5 reps is just as hard, and the stabilizers work near failure too: dozens of muscles at once, at low load. Yes, this is strength training. 2h of Logic beats 6h of weights.

#3 · TRX

Fine for beginners. Much worse for advanced.

What the research says

In older adults, 12 weeks of suspension training built about as much strength as weights. In trained athletes, studies on unstable training like TRX show much smaller gains than weights. We found no TRX trial in advanced lifters.

Randomized trial, Eur J Appl Physiol, 2020 · Cressey et al., J Strength Cond Res, 2007 · Behm et al., Sports Medicine, 2015

What we found

For advanced lifters it falls far behind weights: the load tops out at your bodyweight, and the anchor carries part of the job. The Logic ball has no anchor and no fixed pivot: it moves under you in every direction, about ten times a second.

#4 · Pilates

Great for control. Not for strength.

What the research says

Strong evidence for flexibility and dynamic balance, moderate for muscular endurance. Strength gains: not established.

Cruz-Ferreira et al., Archives of Physical Medicine and Rehabilitation, 2011 (systematic review, 16 studies)

The difference with Logic

It looks like Pilates. It's almost the opposite. Pilates is slow, controlled and predictable. Logic is fast and reactive, and it builds the strength. You keep the control.

#5 · BOSU

A wobble that steals force.

What the research says

Trained athletes who trained on unstable surfaces gained less power and speed than with the same training on solid ground. A meta-analysis of 22 studies does not recommend unstable surfaces for young, healthy athletes who want to perform on stable ground.

Cressey et al., J Strength Cond Res, 2007 · Behm et al., Sports Medicine, 2015

The difference with Logic

A BOSU only tilts slowly and deforms mildly, so the body learns it fast. There is no Reactive Falling Effect. The Logic ball rolls, deforms and springs back at once, too fast to plan.

#6 · Swiss ball

Too big. Too slow.

What the research says

A chest press on a Swiss ball produces about 60% less force than on a bench. The muscles steady you instead of pushing.

Anderson & Behm, J Strength Cond Res, 2004

What we measured

A Swiss ball moves you less than once a second. The Logic ball is 18 to 22 cm and moves you about ten times a second. Even a 30 cm ball gives 30 to 40% less reactive demand.

Our measurements: wrist accelerometry (Apple Watch), jerk and Welch power spectral density, 3 axes, 2 to 12 Hz. Reactive demand is our proxy for how many muscle fibers have to work, not a count of them.

See the full comparison

Common questions

How can Logic Workout outperform weight training for strength?

By taking every muscle near failure, not just a few. A heavy set gets a few prime movers there in 5 reps. On the Logic ball, at the right level, 5 reps is just as hard, and the stabilizers work near failure too. Gym-goers and athletes who switched or swapped 2 hours of their training to Logic all added at least 15% to their PRs in one month.

Isn't this just instability training?

No. Instability training puts a wobble under a lift, and the wobble steals force from the lift. The studies agree it loses to weights, and so do we. Logic Workout is built around the fall itself: catching it is the load. At the right level, 5 reps on the Logic ball is as hard as a heavy set, with every stabilizer near failure too.

Is this Pilates with a ball?

It looks like Pilates. It's almost the opposite. Pilates is slow, controlled and predictable: it builds flexibility and control. Logic is fast, reactive and unpredictable: the 18 to 22 cm ball rolls, deforms and springs back about ten times a second, for 50 times the reactive demand of Pilates in our measurements. You keep the control, and you get the strength.

How much time does the program take?

From ten minutes a day to four hours a week, depending on your goal. Short on time? Do the 3-minute daily challenges. The method's creator advocates two hours a week, four sessions of 30 minutes, for an athlete-level body.

Will it replace heavy lifting?

Unless you are a bodybuilder chasing hypertrophy in one specific muscle, or competing in a lift where the exact movement under load is the event, yes. A heavy set takes a few prime movers near failure in 5 reps. On the Logic ball, 5 reps is just as hard, with every stabilizer working too: 17 times the reactive demand of weight training, in our measurements.

Gym-goers and athletes who switched or swapped 2 hours of their training to Logic all added at least 15% to their PRs in one month. Yes, this is strength training. 2h of Logic beats 6h of weights.

Two hours a week

Hard to believe our results? We get that a lot. Try it yourself.

Note your max today. Swap 2 hours a week for Logic. Check it in a month.

Free for 14 days

Download on the App Store Get it on Google Play

The other Logic apps

Same method, applied to sleep and to breath.

  • The Logic Dreaming app on two phones

    Also from Logic

    Logic Dreaming

    Work with your sleep, not against it.

  • The Logic Breathing app on two phones

    Also from Logic

    Logic Breathing

    Train the breath that carries everything else.