"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." High-intensity interval training (otherwise known as HIIT) may sound, well, intense. And it can be. But ...

As women enter their 40s and beyond, hormonal changes can make it harder to build muscle, maintain energy, and manage body composition. High-intensity training is one of the most powerful tools for ...

I recently decided to completely switch up my half marathon training. I swapped miles for time-based training runs, and because I’ve never been much for speedwork outside my high school cross-country ...