Researchers have built an AI system called Log2Motion that takes the physical motions of smartphone interaction—the taps, the swipes, the scrolls—and thoroughly analyzes every minute muscle stretch and twitch that makes those actions happen. They’re doing this to better understand how our muscles are engaging with our phones and how much physical effort it actually takes to use them.

In all my time doing this, I don’t think I’ve ever encountered a longer scientific journal name than the Proceedings of the 2026 CHI Conference on Human Factors in Computing Systems. Buried inside that tome of a title is a new way to measure the physical effects our smartphones are having on our bodies.

For all the data tech companies take from us with these things, they don’t seem especially interested in data on the physicality of smartphone use. All they know is that you tapped a button. They don’t often know or even care whether reaching that button required a weird stretch of your thumb that slowly develops a muscle strain.

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Log2Motion simulates a digital human body using a detailed AI arm model with 63 muscle-tendon units. The system takes a series of educated guesses on how a real person would have moved to produce the recorded inputs. The AI even accounts for tiny human inconsistencies since human movements aren’t naturally perfect. The researchers call this “motor noise.”

The real breakthrough here is something called “screen mirror,” which lets this simulated AI body interact with real Android apps in real time. That interface between a physics-based body simulation and actual software didn’t exist before now. Because of this, a virtual finger tap or a virtual swirl of a polka ball in Pokémon Go can generate meaningful physical data that researchers can study.

To make sure they hadn’t created a nice illusion of human movements, the researchers tested the system against real human movements, and the results were well aligned. The simulated gestures fell within the natural variation you’d expect if you had a variety of people perform the same physical task.

All of this is an effort to help app developers better understand how real flesh-and-blood people physically interact with software. Instead of waiting for a flood of complaints to come in, app developers may one day be able to identify, say, when a certain button is too far out of reach. Or when certain gestures require unnecessary effort, before the app is ever officially released or even physically tested.  

We spent so much time studying the effects of apps and smartphones on our brains, yet the physical actions required to make all that happen have been woefully ignored for years… until now.