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.

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

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