The implicit assumption is that all of those mitochondria are created equal. That’s where a new paper by Mikael Flockhart and colleagues at the Swedish School of Sports and Health Science in Stockholm picks up. If not all mitochondria are the same, then what exactly do the bad ones look like, and how do we avoid them?

Super shoes have taken over elite road and tracking running in the decade since they first emerged with Nike’s invention of the Vaporfly 4%. One category of runner that hasn’t gotten the same boost that everyone else got when super shoes appeared: trail runners. Research on trail running can be hard to do. Simulating rock and switchbacks on a treadmill in a laboratory poses some readily apparent challenges. Two recent studies provide some answers though.

Is your training app running the show? “All models are wrong. Some are useful.” -George Box It used to be that we decided for ourselves how we were doing. I still remember my old manual training log where I’d enter my mileage for the day and a quick thought about how it went. But the roles have reversed. If training apps and sports watches are the new training logs, then it seems more like the training log is telling us how we’re doing instead. There’s a common favorite way to do this. It’s...