A new wave of research is showing what the old gym myths about stretching got wrong—and what you really need to do to reap its benefits.

Editor’s note: Before beginning any new exercise program, consult your doctor. Stop immediately if you experience pain. As you head into the gym, you likely already have a workout plan in mind. Maybe ...

For many people of a certain age, high school gym class began with reaching for their toes. Then, over the years, we were told it was better to stretch after exercise. It turns out, both those things ...