Moving the arms forward and backward in line with the direction of movement. The arms should not swing across the body and the elbows should point backwards, not outwards.
Swing the arms from the shoulders, not the elbows. Keep the elbows bent and focus on driving them backward.
Hold the elbows at about a 90-degree angle. Allow the elbow angle to fluctuate slightly during the arm swing, but don’t stray too far from 90 degrees (70 to 120 degrees is a good range.)
Have the hands pass the body at about hip height. Avoid holding the arms so high that they pass above the waist or so low that they pass below the hips.
Swing the arms powerfully through a full range of motion. Distance runner’s hands should move from their hip or a bit further back to their chest. When sprinting or running uphill, the hands should move from the back pocket, or a bit further back to the chin.
Keep the shoulders and hands relaxed. The shoulders should be down, not tight, and the hands should be relaxed but stable, not clenched in a fist, hyper-extended, or flopping around.