Run 90' on a flat to rolling course or treadmill.
WU: Keep HR in Zone 1-2 for the first 15' which is a warm-up.
MS: Next 30' is 15 x (1' hard - 5K pace, 1' easy - marathon pace). Return to Zone 1-2 for cool down. Think about form and running pretty. Concentrate on keeping turnover high, don't overstride - run efficiently.