Step 1
Draw a line about a yard long on the pavement. Walk 30 feet forward and draw a similar line on the ground. Set up two markers -- which can be small blocks of wood -- behind the furthest drawn line.
Step 2
Crouch down in the middle of the line without markers. Have a friend say, "Go." Run to the opposite line as fast as you can..
Step 3
Pick up one of the markers when you reach the line 30 feet away.
Step 4
Turn and sprint back to your original line and drop the marker behind the line.
Step 5
Run again to the opposite line and after picking up the second marker, sprint back to the original line. Drop the marker. This constitutes one repetition.