Your next fitness coach could be a robot, but can it really help you?

Hiring a personal trainer is one of the best ways to stay consistent with your workout, push your limits and try new things. But it often costs more than US$100 a session, and getting to and from the gym can be time-consuming.

Over the past decade, fitness apps have been attempting to replicate the personal training experience, and in recent years many have incorporated artificial intelligence, or AI, to generate workouts.

A widening array of products offer custom workouts based on your abilities, goals and available equipment, for much less than a personal trainer (costing typically around US$100 a year instead).

However, some experts warn that, while AI fitness apps are useful for many exercisers, they’re not appropriate for everyone.

WHAT IS AN AI FITNESS COACH?

AI fitness coaching apps create personalised training programmes based on your goals, the type of workouts you want and your equipment.

Unlike ChatGPT, which uses enormous amounts of existing data to predict the next word in a sentence, these apps take an individual user’s data and employ algorithms to create personalised workouts, based on other users’ experiences.

As you complete workouts, the app customises your next training sessions, incorporating feedback you provide about how you felt and your performance – how long it took, how much work you did or how much weight you lifted.

Many of the apps also integrate data from fitness wearables or smartwatches. In the last couple of years, fitness apps have been incorporating more complicated blends of heart rate, mileage and calories burned to create new workouts.

One of the oldest and most popular of these, with more than 55 million subscribers, is Freeletics, which incorporated a form of AI into its program in 2017.

One benefit of such a large subscriber base is that it has an extensive data pool from which to create workouts, helping the AI predict what training would work best for you based on how others performed, said Confidence Udegbue, an executive who directs the development of new products at Freeletics. The app costs about US$100 per year.

A host of other apps have recently launched or incorporated AI into their programs and now offer similar services. Fitness AI, Aaptiv (which is launching a new coach product in May) and FitBod all cost slightly less than US$100 a year. JuggernautAI, which has a strength-training focus, costs US$350.

Some smart home gyms, like Tonal and Tempo, include proprietary equipment with motion sensors that use AI and cameras designed to track your movements and offer feedback on form. Those cost thousands of dollars, plus subscription costs.

In the future, training apps could collect even more data to measure effort – in addition to heart rate and respiration, perhaps eye dilation or oxygenation – and integrate it with what we know about exercise science to give ever more personalised feedback, said futurist and astrophysicist David Brin.

But, he added, more data doesn’t always lead to better advice.

“What’s at issue – as always,” he said, “is whether the output advice will actually be good for you, over the long run.”

CAN AI TRAINERS REPLACE THE REAL THING?

If you’re familiar with the movements an app might suggest, and you’re self-motivated, AI trainers are a cost-effective way to get a customised training plan and shake up your workout routine.

A part of personal training, especially strength training, is thinking through formulas about how many times you perform an exercise (the reps), how many groups of those reps you complete (sets) and how those numbers should change as you progress.

“What AI does exceptionally well is determine sets and reps,” said Cooper Mitchell, the owner and founder of Garage Gym Reviews, who has spent the last 10 years reviewing home gym equipment and technology, including AI-powered fitness apps.

But if you’ve never squatted or bench pressed before, he said, it’s best to learn these movements under the watchful eye of an experienced personal trainer.

Furthermore, computers can learn a lot about different fitness regimens, but they can’t yet replicate the social interactions that make training effective, said Nikola Banovic, an assistant professor of computer science and engineering at the Artificial Intelligence Laboratory at the University of Michigan who specialises in human-computer interaction

“Just because the AI is saying you need to run more,” he said, doesn’t mean you’re “actually motivated to do it”.

This is especially true for veteran athletes, who often say the toughest battles in fitness are psychological, not physical.

“The coach becomes a little bit of a therapist. I text my coach just as often to complain to him as I do to give him the results from training,” said David Tao, co-founder of BarBend, a website about strength training and strength sports.

The existing AI apps can’t provide encouragement or comfort you on an off day. However, Dr Banovic said, in the near future they may use programs like ChatGPT to talk about your workout or offer motivation. Even then, it will be important to consider the value of personal interaction, Mitchell said.

“As humans, we need more than just the workouts that will get us to our goals,” he said. “We need to be inspired and encouraged – that’s something only a real trainer can do right now. I think it will be some time before AI. training does this well.”

By Hilary Achauer © The New York Times Company

The article originally appeared in The New York Times.