Run easily for 10 to 15 minutes, follow with 6 x 20-second strides.
Run for 20-40 minutes (or 3-6 miles) at your half marathon race pace (If you don’t have a half marathon time to base this off, add 15-20-seconds per mile to your current 10K race pace). Every fifth minute throw in a 30-second “burst” at 5K-10K effort followed by an immediate return to half marathon pace.
Mario Fraioli is a senior editor at Competitor magazine. A cross-country All-American at Stonehill College in 2003, he now coaches the Prado Women's Racing Team in San Diego and was the men's marathon coach for Costa Rica's 2012 Olympic team. His first book, The Official Rock 'n' Roll Guide To Marathon & Half-Marathon Training (VeloPress, 2013) is available in bookstores, running shops and online.