This exercise reinforces the arm swing motion you want to have while running, Ashley said. "This is where you get the most power out of your arms."
- Grab your light pair of dumbbells, three to five pounds.
- Sit on the ground with your legs extended and core engaged.
- Swing your arms in a running motion without lifting the dumbbell above your chin. Keep a 90-degree bend in your elbows, and avoid crossing your arms in front of your body. On the backswing, drive your elbow back and up.
- Continue for 30 seconds.