Lacking a clear scientific path, I poked around a little to uncover the best long-run pacing strategy. The contenders included these pace acronyms: EZ (easy, relaxed), MP (marathon pace), LT (lactate threshold, otherwise known as tempo pace), and RTYP, which I made up. It stands for "Run Till You Puke."
Take It EZ
Your EZ pace is about one minute per mile slower than your marathon pace. The many fans of easy-paced long efforts contend that these runs allow you to get in your miles, with all the desired physical and mental benefits, while limiting your risk of injury. To increase your speed, you can enter races, or do faster workouts on other days of the week.
This kind of training worked wonders for Bill Rodgers when he was king of the roads. Rodgers would often race on weekends, and do his long runs on Monday. "I was usually tired from a weekend of travel and racing," he says, "so most of my long runs were at a pretty moderate pace."
Critics point out, however, that slow running makes you slow, which is true if it's all you do. And two-time U.S. Olympic marathoner Pete Pfitzinger cautions that slow running can also become sloppy running after 15 miles or so, which could lead to injuries.
Target Your MP
In recent years, more coaches and runners have turned to marathon pace as the foundation of their long-run strategy. Here's a common approach, supported by many experts, including Jack Daniels, Ph.D., author of Daniels Running Formula, and popular online coach Greg McMillan: Run the first 10 miles of your long run at an easy pace, then gradually accelerate to marathon pace over the last eight to 10 miles. A number of coaches believe in alternating your weekend long runs. That is, do an EZ-all-the-way long run one week, and an MP-based long run the next.
In training for her sensational 2:19:30 marathon in London this past April, Deena Kastor did up to 14 miles of long runs around her MP. "These workouts made her stronger over the last half of the marathon," says her coach Terrence Mahon.
MP long runs also form a cornerstone of the Furman FIRST program, a popular three-day-a-week marathon-training plan. Its 18-week schedule asks runners to increase their long-run pace from marathon goal pace + 45 seconds, to +30, to +15, and then MP itself. "We suggest doing progressively longer segments of the long run at marathon pace until approximately 15 of the 20 miles are at MP," says Bill Pierce, FIRST founder. "Our runners often report that the long runs are faster than they were accustomed to, but with the ample rest days in our program, they are able to maintain pace."
Find Your Tempo
Leave it to Daniels, the master of tempo training, to figure a way to introduce lactate-threshold workouts into a marathon plan. "I favor a variety of long runs," Daniels says. "You just have to be careful that your long run doesn't affect another quality workout that's coming up."
Here's a particularly clever Daniels-endorsed way to do tempo training on a 20-miler. Start with two miles at EZ pace, then do 4 x 2 miles at LT pace, about marathon pace minus 30 to 50 seconds per mile. Between the two-milers, jog easily for two minutes. Finish your run with 10 miles at EZ pace.
Jason Karp likes to use LT pace for the last three to four miles of a long run. "It's a key physiological variable," he says. "If we can improve someone's LT, they'll run a faster marathon."
Run Till You Puke
A few years back, Khalid Khannouchi noted that he took his long runs so seriously that he couldn't sleep for a night or two beforehand, and would sometimes get sick to his stomach after. Since Khannouchi is the only marathoner ever to break 2:06 three times, it seems that there's something to his approach.
According to his wife and training advisor, Sandra, Khannouchi always runs negative-split long runs, warming up for several miles, and then running just 15 to 20 seconds slower than his marathon pace. The last three miles, he goes for broke. "He tries to run them at about his 10-K race pace [4:30 to 4:40]," she says.
Greg McMillan says many of the great Kenyan marathoners do the same. He learned this a few years ago when he was an apprentice to Italian coach Dr. Gabriele Rosa. Rosa encourages his runners, including marathon world record holder Paul Tergat, to start their long runs at a relaxed pace before picking it up to MP pace for the midrun miles. "Then they'll run the last 10 to 30 minutes of the workout like it's a race," says McMillan. He calls this the "fast-finish long run."
So what should you do? If you want to go for the gold, then by all means train like Khannouchi and Tergat. Just be sure to take a Tums before every long run. Otherwise, I'd say that a simple marathon-pace long-run strategy makes the most sense for the most runners. After all, it obeys the essential training precept: the specificity-of-training rule.
I'm going to try this simple pace-progression for my next marathon: Start with five EZ miles and five marathon-pace miles (or whatever distance is appropriate for your fitness). On each subsequent long run, add a mile until you get to nine EZ plus nine MP. At that point, you can either step up to a nice round 20-miler or start tapering for your marathon PR.