A physical therapist explains how a modified side plank with a clamshell strengthens runners’ core and hips to improve efficiency and reduce injury risk.

There’s no shortage of glute-boosting training sessions online – but most overlook the smaller accessory moves that build real strength and balance. One of the most underrated? The clamshell exercise.

I love the clamshell exercise, too. I do this simple movement on the floor, from the comfort of my yoga mat (or carpet), and it's done more for my hip mobility, core stability, and glute (buttock) ...