In 2010, Kika DuBose went to a gym in New Jersey which attracted a number of promising bodybuilders. Gradually, she noticed that most of them weren't flexible enough to hold their hands behind their backs. Many had only limited mobility in their necks. A few couldn't even sit on the ground with their legs straight ahead.

So DuBose, a former professional dancer, started helping the men stretch. The results were immediate: After stretching one guy’s neck, she says, his daily headaches started to disappear. (She hypothesizes that it was because of the improved blood flow.)

But beyond mere flexibility, the lifters also noticed a strange phenomenon: After being stretched, they could also crank out more reps during their workouts. By becoming more flexible, they apparently became stronger—no extra lifting required. Stretching doesn’t just make your show muscles stronger, either—it could be good for your heart, a recent study in Japan found.

I figured there might be something behind this stretching method. So Men’s Fitness sent me, a dedicated gym-going test subject, to visit DuBose at her studio (she has locations in Manhattan and New Jersey). There, she recommended the following five tips that can help anyone improve their fitness through stretching.