Lockin

Build → 100 pushups a day

100 pushups a day, every day, with money on the line.

Spread 100 reps across the day in submaximal sets. Lockin's on-device pose detection counts every rep. Hit your daily target and your money returns. Miss and your stake funds the charity you chose. The hardest part is showing up for the last 20.

Download on iOS Download on Android

Suggested starting contract

$5/day against missing your daily target of 100 pushups.

Why willpower fails to start this

The 100-pushups-a-day target sounds simple and fails for a specific reason: most people attempt all 100 in a single session, run into fatigue around rep 35, and declare the method too hard before they have given the actual strategy a trial. The actual strategy is grease-the-groove, a method Pavel Tsatsouline formalized in "The Naked Warrior" (Dragon Door, 2003). Tsatsouline's central argument is that strength is partly a skill — a pattern of neural recruitment — and that frequent submaximal practice builds that pattern more efficiently than grinding to failure once a day. Ten sets of ten, distributed across waking hours, leaves no single set hard enough to create crippling fatigue. Each set reinforces the motor pattern. By evening, 100 reps have accumulated without a single set that felt punishing. The strength-science literature supports this structure. Eric Helms, PhD, co-founder of the MASS (Monthly Applications in Strength Sport) research review and Research Fellow at Auckland University of Technology, and Brad Schoenfeld, whose 2016 and 2017 meta-analyses examined volume and frequency effects on hypertrophy, both point to a consistent finding: distributing training volume across multiple sessions per week — or per day — produces adaptation at least as efficiently as concentrating it, and often more so for novice and intermediate trainees. Borge Fagerli's myo-reps framework, developed over decades of applied coaching, formalizes a related principle: submaximal "activation" sets followed by short-rest clusters maximize the stimulus-to-fatigue ratio, extracting hypertrophic signal without the systemic cost of grinding to failure. The behavioral failure mode, however, is not biomechanical. It is motivational. Greasing the groove requires completing small sets at odd moments — before a meeting, before lunch, before bed — none of which feel urgent or satisfying in isolation. The gap between 80 reps and 100 reps at 9pm feels irrelevant after a long day. Kahneman and Tversky's prospect theory (Econometrica, 1979) identified loss aversion as the mechanism that closes exactly this gap: the psychological weight of a potential loss registers roughly twice as intensely as an equivalent gain. A $5 stake on today's contract is not $5 of motivation — it behaves closer to $10 of aversion pressure. That pressure is present at the moment the rationalization happens, which is the only moment it needs to be.

How Lockin verifies it

Lockin verifies pushup completions using on-device pose detection. You lay your phone face-up on the floor below you and select the Pushup challenge type before starting a set. The front camera feeds into a real-time pose-estimation model that runs locally on the device — no video is uploaded or stored. The model tracks key body landmarks, primarily shoulder, elbow, and wrist positions, and registers a valid rep when your chest descends within a defined distance of the floor and your elbows reach the required angle on the way down, followed by full extension on the way up. Partial reps do not count. The rep counter displays on screen as you move so you can see the live tally. Each completed set appends to your daily total. You can do sets across the day in as many batches as you like — the app accumulates the count toward your daily target. Reps performed without the camera-tracked session running do not count toward your Lockin contract. The system is designed to capture distributed grease-the-groove style training: you open the app, knock out a set, and move on. A camera-tracked session that brings your verified rep count to your target before your daily deadline marks the day done. The verified count provides an honest record of what was actually completed.

Set up a 100 pushups a day contract in 5 minutes

  1. 1

    Install Lockin

    Free download on the App Store and Google Play. Account creation takes under a minute using email or Apple/Google sign-in.

  2. 2

    Choose the Workout Pose challenge type

    Select Workout Pose from the challenge picker, then select Pushups as your exercise. This activates on-device pose detection for rep counting.

  3. 3

    Set your daily target

    The default is 100 pushups per day. You can lower the target for your first contract if you are building from a lower base — 50 or 60 reps per day is a legitimate starting point.

  4. 4

    Set your daily deadline

    By default the deadline is end-of-day — 23:59 in your local timezone — so your verified reps need to be logged before midnight. Tap Set deadline in the wizard to pick an earlier time on a 24-hour picker; 9:00pm is a strong default for the pushup challenge because it forces the last set out of the bedtime zone, where most missed sets actually die. An earlier deadline raises both the difficulty and the reward: tighter deadlines unlock higher Locks and XP rewards. The deadline is set once during contract creation and applies to every scheduled day for the life of the contract — it cannot be edited mid-contract.

  5. 5

    Set your stake and choose your charity

    The default stake is $5 per day — enough that skipping the last set at 9pm feels like an actual cost, not a rounding error. Then select from Lockin's vetted charity list across categories including climate, mental health, animal welfare, and digital literacy; if you miss your daily target, your stake funds that cause. Lockin charges a small platform fee to cover payment processing and operations.

  6. 6

    Plan your sets before day one

    Decide in advance when your sets will happen — 10 reps before each of ten natural stopping points in your day works well. The grease-the-groove method only works if the sets are scheduled, not spontaneous.

  7. 7

    Confirm and lock in

    Your stake is held securely by Stripe. Complete your 100 verified reps before your daily deadline in your local timezone each day for your contract to clear.

From Lockin's data

In the Lockin beta, workout-pose contract users who distributed their reps across four or more separate sessions showed meaningfully stronger completion rates in weeks two and three compared to those attempting large single-session sets. The grease-the-groove structure — small sets at natural breaks — appears to reduce the perceived effort of any individual session to the point where avoidance behavior decreases sharply.

"I failed the 100-pushup thing twice before because I kept trying to bang them all out before bed and always stopped at 60 something. With Lockin I do 10 reps maybe eight or nine times through the day. By dinner I usually only need 20 more and those feel easy. The $5 is what gets me off the couch for that last set."

— Anonymous beta user, pushup challenge, 5 weeks active

Common questions

Do I have to do all 100 pushups at once, or can I split them across the day? +

Splitting across the day is the intended approach. When you configure the contract you pick how many sets you will do and how many reps each set should be — sets from one up to ten, and reps per set from a fixed list that includes 5, 8, 10, 12, 15, 20, 25, and 30. Ten sets of ten is the canonical structure for a 100-a-day target, drawn from Pavel Tsatsouline's grease-the-groove method: no single set is hard enough to cause significant fatigue, which means you can maintain form and frequency across the full day. The app accumulates your completed sets across as many separate sessions as you run through the day. The day clears once you have completed the sets you committed to, before midnight in your local timezone.

What if my form breaks down — does Lockin still count the rep? +

Lockin's pose-detection model registers a valid rep when your body passes specific position thresholds: elbows at the required angle at the bottom of the movement and full extension at the top, with your body in a recognizable plank alignment. A rep where your hips sag significantly, your range of motion is partial, or your body position does not register the required landmarks will not count. This is intentional. Counting only valid reps gives you honest data on what you actually completed and removes the temptation to rush through low-quality reps to hit the number faster.

Where does the forfeited money actually go? +

Forfeited stakes go to a registered charity from Lockin's vetted list. You choose the charity from categories including climate, mental health, animal welfare, and digital literacy when you set up the contract. Lockin charges a small platform fee to cover payment processing and operations. Refer to the transparency page inside the app for charity-by-charity tallies.

Does Lockin count pushups in real time, or do I submit at the end of the day? +

Lockin counts in real time. Each time you open the app and run a set with your phone's front camera, on-device pose detection registers each rep as you complete it and adds it to your daily total immediately. You can check your running count at any point during the day. Most users complete their daily target across multiple short sessions, with the app accumulating each verified set. Your total must reach the target by your daily deadline in your local timezone for the contract to clear. There is no end-of-day manual submission — only verified reps counted through on-device pose detection count toward your contract.

How does the daily deadline work, and can I change it? +

Every contract has a per-day deadline by which your prescribed reps must be completed in a camera-tracked session. The default is end-of-day — 23:59 in your local timezone — so the day clears any time your verified count crosses 100 before midnight. During the 7-step contract wizard you can tap Set deadline and pick any earlier time on a 24-hour picker; 9:00pm is a popular choice for the pushup challenge because it forces the final set out of the pre-bed window where late evenings tend to swallow exercise plans. The deadline you set applies to every scheduled day for the life of the contract. Tighter deadlines unlock higher Locks and XP rewards, since an earlier cutoff is meaningfully harder than midnight. The deadline is locked in at contract creation and cannot be edited mid-contract — that immutability is what makes it function as a precommitment rather than a movable goalpost.

Other habits people build

Stop deciding. Start staking.

Free to download. You set the target, the stake, and the charity.

Download on iOS Download on Android

Author

The Lockin Team — Lockin Editorial

Last verified