A San Francisco gym went viral for a sign about vibe coding. The gym says it's an AI-generated fake.

• A sign instructing San Francisco gym-goers not to vibe code between sets went viral.
• The sign was an "AI-generated fake," according to the gym.
• Amid tech's vibe-coding obsession and fitness boom, it's no surprise the image has gotten heat.

Don't hog the leg press while prompting Claude.

A screen with the logo of Fitness SF, a Bay Area chain of gyms, went viral among techies on X and Instagram on Monday. The image instructed gym-goers to refrain from writing code or prompting AI during their workouts. "Be present. Lift harder. Ship later," the image reads.

Troy Macfarland, Fitness SF's director of marketing, said, however, that the image was an "AI-generated fake." The gym does have etiquette signs that mention phone usage and being courteous, he wrote, but none mention vibe coding.

"This person altered our actual images displayed on the screen," Macfarland wrote. "I will give an 'A' for creativity to him."

It's not clear whether the image was generated with AI, Photoshop, or some other tool. Ian Brash, whose post with the image got almost 7,000 likes, did not respond to a request for comment.

In San Francisco's AI mania, it's no surprise a sign like that blew up on X. Techies weighed in, cracking their own jokes about how tied they were to their coding agents.

One X user told Fitness SF to give their copywriter a raise. A Cognition engineer said that vibe coding between sets was encouraged at his company's gym.

"Vibe coding at the gym?" one X user wrote. "You're worried about the wrong weights."

One reaction image often appears in the comment sections of posts like this one. It shows a muscled man, holding a giant nuclear bomb in his hands, jumping into the city of San Francisco. One VC posted it with the message: "Even I have limits."

Claude Code and cardio

The sign tapped into two of the buzziest subcultures in tech.

First, there's AI coding. Ever since the launch of Claude Code and OpenAI's Codex, engineers have been tied to their phones (or walking around with half-open laptops) to continue building. Some techies told Business Insider that their love of vibe coding created distance between them and their girlfriends.

Then there's the gym. Tech bros are getting fit, pumping themselves full of peptides and getting shredded at early-morning Equinox sessions. A developer at the gym used to be an anomaly; now, it's the norm.

Some techies seemed skeptical from the start. One X user quoted the post, writing that there was "no way this is real."

Another user responded that they didn't know about that specific sign, but they did know about the underlying issue. "This is a real problem at the Equinox in San Francisco," they wrote.