Others made "push-up battles with strangers" big on TikTok, and an older developer with 120M installs brought it to Android

Pushup Legends: Duel Arena is an app that counts push-ups with your phone camera and lets you compete in real time against other people's 1v1. The mechanic wasn't invented here: this summer several iOS indie devs made it big through TikTok shorts. It only reached Google Play in Sep 29, built by the developer behind AZ Screen Recorder (a phone screen recorder, 120M installs). About 40k installs in five weeks, mostly from cheap markets like Turkey, Nigeria and Indonesia. It's worth a look because it shows a playbook: take a mechanic already validated on iOS and move it quickly to Android. The category itself is already crowded.

A 2.35M-view video

In 2026 July 17, the TikTok account @repchampapp posted a video captioned only "Easy win i guess 😂". It shows two people racing push-ups in split screen, with each side's rep count ticking up live. By Nov 6 it had 2.35M views. Three days later the same account posted "First time losing 😭", which got 2.98M views. That was RepChamp: Fitness Duel, an iOS app by an indie developer. Earlier, Push Up Arena had a level-based video on iOS in May 8 that reached 3.35M views.

By late September, "pick up your phone, find a stranger, and race them for a minute of push-ups" had been watched by millions of people on TikTok. In Sep 29, Pushup Legends went live on Google Play, with "AZ Screen Recorder" listed as the developer.

What it is

The store page is straightforward: prop the phone on the floor with the camera facing you so it can see your arms and hips. Tap "Find opponent" to be matched with a real person within seconds. The camera only counts full reps; shallow ones trigger "Go deeper", and rushed ones trigger "Too fast!". Whoever does more reps wins. Detection runs on-device, and video is not uploaded.

Beyond battles, it bundles the selling points of several similar apps:

• Ranked play: a ladder for each exercise, from Bronze to Legend, reset every season;
• Boss fights: every rep chips away at monsters on the map, with a boss at the end of each zone, very much like the approach of Pushup RPG;
• Guilds and leaderboards: daily, weekly, and all-time rankings, with your reps contributing to your guild;
• Streaks.

It makes money through ads, in-app purchases ($2.99–18.99 for one item, per the Google Play page), and the Legends PRO subscription. Push-ups are free in all modes. PRO removes ads and unlocks squats, sit-ups, pull-ups, and planks, plus the ability to create your own guild (Google Play page, 11-06).

How much it grew

• Installs: cumulative on Google Play worldwide, 10-29 is 14,199,11-06 is 39,850, about 26k added in just over a week.
• Trend: per third-party estimates, it was only getting a few hundred installs a day until mid-October. It jumped to around 1,500 a day in late October. The peak from 10-29 to 11-02 was 3,500–4,300 a day, and it fell back to about 2,100 in early November (estimate).
• Charts: only charted on the free chart in Health & Fitness. Its best rank was #49 in Turkey (10-30), and it later dropped to #78 11-06. It ranked 100–200 in Nigeria, Indonesia, the Philippines, Thailand, Saudi Arabia, Vietnam, and Malaysia. It has never charted in the US, Europe, Japan, or Korea, and never on the Top Grossing chart.
• Ratings: 306 in total, all 5 stars, and only 4 with written reviews (Google Play, 11-06). RepChamp, the same category, has 9,248 ratings, 72 of them 1 stars, which looks far more normal.
• iOS: there is an iOS version (seller Mai Huy Mao) with 0 ratings in the US store and no chart history. It has mostly gotten traction on Android.

Compared with its peers, 40k isn't that big:

Separately, the iOS app Push Up Arena has 4,023 ratings in the US store (App Store, 11-06). Push Up Time, which unlocks your phone by counting push-ups with the camera, is a different approach, with 530k installs on Android.

Where users come from

The answer isn't on TikTok. Searching "pushup legends" only turns up unrelated push-up videos. It has no official account, and no creator carrying it was found. The category's TikTok heat comes from rivals like RepChamp and Push Up Arena, plus @pushduel.app, which appeared in October (one video at 380k views, 10-10).

Its traction looks bought or transferred from its own app. The following are inferences, with no direct evidence:

• The curve opened up abruptly in mid-October, in a step shape rather than a slow word-of-mouth spread.
• The countries where it charted are all cheap markets like Turkey, Nigeria, Indonesia, and the Philippines, exactly the group where Google app ads are most commonly run. There are none in the US or Europe.
• The app contains ads, and the iOS version's privacy labels say it collects location, identifiers, and usage data "used to track you", which suggests ad and attribution tools are installed.
• The same developer also runs AZ Screen Recorder (121M installs) and Reverse Audio (up 475k in a week). Cross-promoting a new app from an existing one costs almost nothing.

There are also two supporting tactics. The first is store search: the title is stuffed with Pushup, Duel, and Arena, and the description repeats push-up 1v1, push-up PvP, and fitness battle game over a dozen times, so anyone who sees an opponent's video and searches "push up duel" in the store has a chance to find it. The second is ratings: all 306 ratings are 5 stars, likely because the rating prompt only appears after a user wins a match. It could also be manipulated (inference). Either way, it lifts store-page conversion.

Why it could take off

Nothing about the product is unique. Battles come from RepChamp and Push Up Arena, boss fights from Pushup RPG and Push Up Boss, and guilds and multiple exercises are add-ons. What really sets it apart is who built it and where:

1. The demand was created by others at their expense. From 7 to August, RepChamp's six videos added up to about 7.8M views (TikTok, 11-06). The idea of "push-up battles with strangers" was already known and wanted.
2. The originators were all on iOS. RepChamp's Android version only came out at the end of August, and Push Up Arena is iOS-only. Android and emerging markets were not seriously pursued at first.
3. The veteran developer moved fast. Three weeks after launch, two versions shipped in October 23 and 30 days apart, adding guilds, fixing counting fairness, and adding win-streak reminders.
4. They had distribution ready. Ads, in-app purchases, and subscriptions were already set up, so they could buy installs in cheap countries, and they had an app with 120M installs on hand to cross-promote.

Crowded or not

Very crowded. The category is already hot, with lots of copycats. From 5 to October alone, iOS and Android saw more than a dozen rivals appear, including Clash of Pushups, PushDuel, Push Up PvP, RepStrike, PushRush, PushRank (a Show HN that reached Hacker News), Repborne, Rep Battle, and PushOff. Most have single-digit to a few dozen ratings. On Nov 6, new TikTok accounts were still posting "App name: RepStrike - push up battle".

Interest is also declining. RepChamp's July videos regularly hit one to two million views, while October's ones got only tens of thousands (TikTok, 11-06). Pushup Legends' own daily installs also fell from a peak of about 4,000 to about 2,000.

If it were you

C: you can learn from it, but following this app isn't worth it. It took off because of a developer with 120M installs and distribution power that followers don't have. Anyone can build the format, but a dozen people had already done so by 5 to October.

• Who it suits: small teams that already have a few Android apps, existing traffic to cross-promote, and experience running Google app ads. What you should take is the playbook, not this product.
• Who it doesn't suit: indie developers who want to build "yet another push-up battle". There's no product barrier, RepChamp and its peers already hold the TikTok spot, and you won't get cheap emerging-market traffic. For someone who can code but can't buy traffic, this is basically zero.
• How to do it: each week, search TikTok for "app" plus a category keyword and look for indie apps that had a million views in the past 4 to 8 weeks but only exist on iOS. Ship an Android version in 4 to 6 weeks: copy the core mechanic, add the selling points of other rivals in the category, stuff the title and description with the terms users search for, keep the core free, sell advanced content through a subscription, and add ads. If you still want to work in camera-based fitness, stop building push-up battles and find a movement or audience nobody has covered yet, such as seated exercises for seniors, jump rope for kids, or Chinese, Japanese, and Korean markets.
• How to get users: start by driving traffic from your own app. Without one, run small test budgets on Google app ads in cheap emerging markets. Only prompt for ratings after a user wins. Ride the buzz of rivals on TikTok instead of trying to create your own.
• Timing: this playbook's window is the 1 to 2 months after the originators blow up, before their Android versions stabilize. The push-up battle wave was already past by October.
• What would mean this read is wrong: ① if after December Pushup Legends still holds several thousand installs a day, or charts in any country's Top Grossing, that means the bought traffic pays back and the category still makes money on Android; ② if a big company (Google Fit, Apple Fitness+, Keep, or similar) launches camera-counted battles, small teams should stay away from this area; ③ if RepChamp or Push Up Arena publicly discloses monthly revenue and the figures are sizable, the "category already packed" judgment needs revisiting, since the high-spend end may still have room.