Can our workouts be shaped by what our friends do?

That question is at the heart of an important new study of exercise behavior, one of the first to use so-called big data culled from a large-scale, global social network of workout routines.

The researchers focused on running, because so many of the network participants were runners. And what they found suggests that whether and how much we exercise can depend to a surprising extent on our responses to other people’s training.

The results also offer some practical advice for the runners among us, suggesting that if you wish to improve your performance, you might want to become virtual friends with people who are just a little bit slower than you are.

There have been intimations for some time that aspects of our lifestyles and health can be contagious. Using data from surveys and postings on social media, scientists have reported that obesity, anxiety, weight loss and certain behaviors, including exercise routines, may be shared and intensified among friends.