This summer, I went on one of the most visually stunning runs of my life. My path took me to the top of a 16th-century fort in Siena, Italy, as the rising sun lit the surrounding rooftops a brilliant yellow. But as much as I enjoyed the experience, I couldn’t shake the feeling that it somehow didn’t count, that it was less legitimate than my usual runs.

The reason: I wasn’t connected to wi-fi, which meant I couldn’t track myself with my Runkeeper app the way I usually did. Without it, I had no way of knowing if I was running as fast or as long as my marathon training plan dictated. I also worried that the friends who followed me on Runkeeper would see that I hadn’t logged anything all week and assume I’d been slacking—both silly things to worry about while enjoying such beautiful scenery, I know. But I also know I’m not the only one who has these anxieties.

Anybody who’s noticed the surge of sweaty Sunday-morning photos on their Facebook feed can likely vouch for the fact that marathons have recently exploded in popularity. To put it in perspective, during the first “running boom” in the 1970s, around 25,000 people in the U.S. ran marathons each year. Nearly twice that number ran in the New York City Marathon on November 1—and that’s just one of 1,200-plus marathons that now take place in the country annually. According to Running USA, an organization that tracks the sport’s growth, a record 550,637 people finished the 26.2 mile distance in 2014.

Running USA has also found that 52 percent of runners today track themselves with some sort of GPS-enabled device, like a smartphone, a fitness tracker, or a specially designed running watch. This statistic has likely played a role in running’s growing appeal—the influx of easily available tracking information has lured people to the sport, and kept them going, by making it possible for anyone to see in real time how it’s affecting their bodies. These apps and gadgets allow people of all skill levels to run more strategically—and to stay motivated, which is very likely the biggest hurdle to becoming an after-work endurance athlete.

It’s a change that’s happened fairly quickly. The first GPS-enabled watch aimed at runners is just over a decade old; it was introduced in 2003 by Garmin, a GPS-technology company that initially developed products for the military. In 2006, Nike launched the Nike+iPod Sports Kit, which tracked runners’ distance and pace through a sensor inside a Nike shoe, connected to a receiver plugged into an iPod. It was a hit, but was quickly eclipsed by the iPhone: When the App Store launched in 2008, with MapMyRun as one of its first apps, just about anyone had access to the type of data previously only available to elite athletes.

“Run-tracking technology has traveled light-years in the past 25 years,” says Bryan Boyle, the gear editor at Runner’s World magazine. “Back then, to track distance, we either used the track or a pre-determined route using the car’s odometer. Maybe we used a Swatch to measure time.” Today, free smartphone apps give runners information on pace, distance, and elevation. If they upgrade to a top-tier watch, they can find out things like the number and length of their steps, their heart rate, even the estimated volume of oxygen they consume per minute and their vertical oscillation (the amount they bounce up and down on each stride).

All this information can act as a reward and a motivator for the runner. “It’s one thing to hear encouragement from a coach,” Boyle explains. “It’s quite another, however, to digest and appreciate—at a glance—progress made during weeks and months of running. Miles logged piling up. Pace per mile improving.”

In some cases, these reminders can make the difference between new runners pushing forward through an exhausting marathon-training program and simply giving up. “It has a self-reinforcing function,” says the sports psychologist and Temple University professor Michael Sachs. “You have charts and graphs to show your progress. When you’re meeting your metrics, it builds self-esteem, making you feel more competent and motivated to keep running.” Knowing that I’ll be able to see evidence of my improving distance and pace—and that other people will be able to see those numbers, too—has often been the thing that pushes me out the door. I doubt I’m the only one who’ll dash up and down the same block a few extra times to record exactly five miles rather than calling it in at 4.6.

But run-tracking technology doesn’t just help runners train harder. It also gives them the power to train more intelligently, doing what a coach might do for professional athletes. Recreational runners today no longer have to guess how far or how fast they’ve run, or what their body is doing and how it’s adapting. If they can monitor their heart rate, they can make sure they’re hitting the most strategic pace on each run, which can significantly increases their odds of having a positive experience on the course during race day.

Many apps are specifically designed to win over the ever-growing market of new runners: The average pace among Runkeeper’s 50 million users is over 11 minutes per mile, which in a marathon would make for a time just under five hours. “It’s about taking the sport that the hardcore [runners] know and love and packaging that in a way that’s really approachable,” says Jason Jacobs, the CEO of Runkeeper. Along with tracking data, the app offers training plans, tips, reminders to work out, and rewards for accomplishing personal records. It takes advantage of the data runners gather to keep them running—and, of course, using the app more often. “It’s about patting them on a back when they do well, giving them a gentle kick in the butt if they’re slacking,” Jacobs says.

This year, the San Francisco Marathon partnered with Runkeeper, as well as the popular step-tracker Fitbit and fitness-app FitStar. “We see wearable and mobile technology as one of the most exciting things happening in the sport right now,” says Michelle LaFrance, the SF Marathon’s marketing director. “It’s driving the democratization of running.” She argues that the social element of this technology—like my ability to see friends’ activity on Runkeeper, and to display my own for their consumption—is driving more runners to the sport. “When you track yourself and then you share that on social media, you become a force of inspiration in your network,” she says. “We see a huge correlation between the volume that runners share and the number of runners that they get to come run with them.” According to Running USA, almost 80 percent of runners have posted race photos and 62 percent have shared results on social media.

No matter how much technology can enhance the experience of running, though, many veteran runners argue that the biggest allure of the sport remains the chance to go off the grid for a little bit. Race training offers a rare chance to get outdoors, away from the computer, for an hour or four. “There’s so much more to the experience than metrics,” adds Boyle. “Fresh air. Camaraderie. Travel. Shoot, just overall feeling better.”

Like any good trend, run-tracking has already experienced its backlash— the term “running naked,” without any tech. Many runners now deliberately leave their watches and phones at home in order to better tune into their bodies—or say, enjoy the Tuscan scenery. There’s no app for that.