Although Lycra-clad runners have been taking to streets and parks for decades, they’ve become ubiquitous in recent years. There are now 10.5 million runners in the UK, and the growth in related apparel and apps shows how mainstream it’s become. Why exactly has running gotten so big?

Why does a beer taste better after a hard day's work? Why do we feel less guilty eating cake after a workout? The answer lies in the balance of effort and reward, and brands often play on the emotions formed by this dynamic. But does the amount we value something just depend on the effort we put in?

Strava, the socially focused, GPS-powered activity tracker, has taken the fitness world by storm. It’s had an especially profound impact on the world of cycling, with thousands of riders going to extreme lengths to claim the virtual prizes it offers. But what makes the platform so addictive?

Extreme sports have long been associated with risky behaviour, yet you’re fifty times more likely to pick up an injury playing rugby than rock climbing. Now, some of these supposedly perilous pursuits may be making their way into the 2020 Olympics. So is ‘extreme’ about to go mainstream?