If you’ve been a regular reader of Master Class over the years, you’re familiar with my affinity for core training as a method of strengthening “from the inside out.” Core training is an umbrella term ...

The core gets a lot of attention when it comes to aesthetics. But your torso muscles—which include your abs, back, glutes, and hip flexors—play a crucial role in running that goes way beyond looks.

Core training has become a consistent pillar in the worlds of fitness and strength training. While health care professionals agree on its importance, there is little consensus on what truly ...