A Weird Tip Helped Me Master My Arm Swing—and Run Faster. You Can Use It to Unleash Your Speed, Too.

The key to faster running may not be in your legs, but in your arms.

Here’s How to Tell If You’re More Aerobically or Anaerobically Fit—and Ways to Get Better at Both

To test aerobic fitness, Matlock suggests running a one-mile time trial, which means doing a mile at an all-out effort.