The ultracompact, platform-agnostic, user-configurable mobile fitness device that Dr. Michael Joyner showed off at a recent sports technology conference caused a stir. The attendees had gathered to ponder the future of high-tech performance enhancement.

Joyner, an expert in human physiology at the Mayo Clinic, had a jump rope.

Wearable fitness technology has completed its 10,000-step march to ubiquity. More than 13 million fitness trackers, made by companies such as Fitbit and Jawbone, were sold last year, with a total cost of $1.5 billion — more than double the 2014 total. The market is projected to be worth more than $50 billion a year by 2018. Smart watches and mobile phones are adding fitness-tracking abilities, GPS devices and heart-rate monitors keep shrinking, and new sensors promise to analyse your running stride or your sweat as you go.

Of course, like any megatrend, the rise of mobile fitness gadgetry has inspired its share of contrarian views. Joyner’s jump rope was a reminder that the fundamentals of getting fit remain simple — a message he proffers “whenever people start going off the gizmo ledge”.

That’s not the only reason for scepticism. Last year, an editorial in The Journal of the American Medical Association titled ‘Wearable Devices as Facilitators, Not Drivers, of Health Behaviour Change’ cited a survey that found that more than half of people who’d bought a fitness tracker eventually stopped wearing it, and of those, a third quit within six months.

Other critiques range from the technical to the philosophical. Fitbit faces a class-action suit, filed in January, alleging that the wrist-mounted heart-rate monitor in some of its models is inaccurate to a potentially dangerous degree. In February, researchers in Canada reported that most fitness trackers leak personal data via Bluetooth in a form that can easily be captured by hackers.

An initiative at Oral Roberts University requires freshmen to wear a Fitbit and grants school administrators access to the data to ensure that they’re meeting the minimum 10,000 steps a day mandated by the school’s ‘Whole Person Education’ programme — precisely the sort of pseudo-benevolent surveillance that may soon be emulated by employers and insurance companies, according to watchdogs. Florida-based Toonari Corp, for example, promises to guide insurance companies through subpoenaing activity tracker data in fraud cases.

Then there are the philosophical objections. These range from denouncing the overmedicalising of everyday life thanks to nonstop monitoring of vital (and not-so-vital) signs to critiquing the transformation of exercise into unpaid labor and a source of profit for corporations like Nike.

These are all legitimate concerns, but they miss a more fundamental question about our rapid adoption of wearable fitness tech: Is the data we collect with these devices actually useful?

For this to be true, the wearable has to be telling you something you don’t know. Your device’s digital output, with its decimal points and automatically uploaded charts, certainly seems more accurate and richly detailed than the everyday sensory data you collect automatically from your body. But whether it really is remains an open question.

In September, in The British Journal of Sports Medicine, Australian researchers published a review of studies that compared subjective and objective measures of “athlete well-being” during training. The objective measures included state-of-the-art monitoring of heart rate, blood, hormones and more; the subjective measure boiled down to asking the athletes how they felt. The results were striking: The researchers found that as the athletes worked out, their own perception registered changes in training stress with “superior sensitivity and consistency” to the high tech measures.

Outsourcing your self-monitoring to a gadget may have another downside. Steve Magness, a track coach at the University of Houston, recently drew on arguments from Matthew Crawford’s book The World Beyond Your Head to argue that running with a GPS watch “slackens the bond between perception and action”. In other words, when you’re running, instead of speeding up or slowing down based on immediate and intuitive feedback from your body and environment, you’re inserting an unwieldy extra cognitive step that relies on checking your device as you go.

None of this adds up to a case that wearable fitness technology is a waste of time. For many people, the primary purpose of an activity tracker like a Fitbit is motivation. Simply knowing how many steps you take, or how much sleep you get, will spur you to seek more, especially if you’re comparing and competing with your online peers — a big difference from the un-networked $2 (Dh7.35) pedometers that came in cereal boxes a decade ago.

There’s reasonable evidence that this approach has useful effects, at least in the short term. In one study using activity trackers published in February, participants increased their daily step count by 970 after six weeks, an amount that previous studies have linked to improvements in body mass index and insulin sensitivity. Even if it’s true that more than half of users eventually stop wearing their devices, it’s still a laudable outcome that several million people exercised more than they otherwise would have for a year or two.

Ultimately, it is those aggregate numbers that offer the most exciting possibilities: The collective data stream from our devices amounts to by far the largest and most comprehensive observational health trial ever conducted. We have the data; now we just need to figure out what it means.

Technology companies are taking the first steps. Rather than simply tracking your individual heart rate, calories burned and so on, they want to use that flood of data to enable us to make more informed decisions. Under Armour, for example, just announced a partnership with IBM to provide “cognitive coaching” that will crunch all your tracked data, and compare it to data from millions of others like you, in order to offer smarter advice on how to exercise, eat and sleep. Other wearable-tech companies are pursuing similar projects.

Health researchers also want to use your tracked data to figure out what works in the real world to improve health and fitness, rather than testing theories in the artificial conditions of the lab. An analysis of in-the-wild data from 4.2 million MyFitnessPal users, for example, recently yielded unexpected insights into the habits of successful weight-losers compared with unsuccessful ones: They ate nearly a third more fiber, and 11 per cent less meat. And the dietary changes the successful dieters made between 2014 and 2015 bucked broader trends: They consumed more grains, cereal and raw fruit, but fewer eggs.

As prosaic as it sounds, this is the greatest promise of the wearables revolution. Once the novelty of tracking your exercise habits wears off, knowing how many steps you took today or what your resting heart rate was yesterday soon loses its interest. But together, 100 million of us wearing wristbands could uncover some truly valuable insights into what works to make us healthier and fitter.

In the meantime, you could do worse than use the gadget that’s in Mike Joyner’s carry-on bag. That jump rope will push your step count through the roof.

— New York Times News Service

Alex Hutchinson writes the Sweat Science blog for Runner’s World magazine.