The Art of the Long Run
by Matt Fitzgerald
Incorporating long runs into marathon training is not difficult, yet it's not completely intuitive, either - and mistakes happen. However, decades of evolution in marathon training have yielded a very reliable set of guidelines for the process with universal applicability. The long run is the most important workout in any runner's marathon training regimen. Whether you're a first-timer looking just to finish or an elite runner aiming to win, you must incorporate long runs into your program in a sensible way in order to achieve your goal. Running long maximizes certain physiological adaptations that you need for an optimal marathon performance. The most important function of long runs is to increase your body's ability to conserve muscle and liver glycogen by enhancing its ability to draw energy from fat and blood glucose at marathon pace. Glycogen depletion is nearly always the ultimate performance limiter in a marathon. Long runs also enhance your body's oxygen consumption capacity, which helps to increase your marathon pace. Along with these physiological adaptations, long runs also prepare you mentally for marathons by increasing confidence, developing your feel for pace and getting you used to the feeling of running out of gas!
Your long runs should be bunched toward the end of your training program - for two reasons. First, you have to build up to them. Second, if you stop doing them too long before your marathon, your ability to conserve glycogen will decrease from its peak by race day. This is known as detraining, and it's not good. Begin doing long runs about 18 weeks before race day, if you're training for a peak performance (i.e., a first marathon or a personal best). Then do them every other week, increasing the duration each time, until four weeks before race day, when you will do your longest run. Two weeks before your marathon, do a last long run of about 15 miles. These guidelines apply to beginners and veterans alike.
If you're a first-time marathoner just looking to cover the distance, your longest run should not exceed 20 or 22 miles. If you're an experienced marathoner with a time goal, the duration of your longest run should roughly match your target marathon time, up to a maximum duration of 3:30. In either case, each long run should be a little longer than the last. For veteran runners, each run should be very slightly longer than the preceding one; the length of the first long run in the training program should not be less than about 15 miles. Beginners are better off following the 10% rule: each long run should be approximately 10% longer than the previous one. First-timers who perform their first long run 18 weeks out and build up to 20 miles should cover about 8.5 miles in that initial long run. For beginners and veterans alike, the first long run should be only slightly longer than the longest run completed in recent training. (In other words, there's a fine line between a short long run and a long regular run!)
Here again, runners looking just to finish a marathon should proceed differently than those chasing time goals. The former are best advised to perform their long runs at about the pace they expect to maintain through the marathon itself. You really want to "groove" that pace if you've never completed 26.2. Experienced marathoners should run between 45 and 75 seconds per mile slower than marathon pace. Feel free to play around with pace, sometimes starting slow and finishing fast, sometimes working the hills, and so forth. Time-goal runners should do some marathon-pace running, too, but probably not in the context of long runs. Instead, such runners might do two or three marathon-pace runs of 10-15 miles on alternate weeks (that is, non-long run weeks) during the peak portion of the training cycle
Runners should make the conditions of their long runs as race-specific as possible. I'm talking about terrain, primarily. For example, the Boston Marathon features long, gradual downhill stretches that can subtly destroy a runner's quadriceps. In training for Boston, you should try to incorporate similar stretches into your long runs. Indeed, if you have the opportunity, do at least one long run on the course itself. A possible exception to this specificity rule is pavement. If you can do a large portion of your long-run mileage on accessible dirt trails, by all means do it, for the sake of injury prevention. You should also perform at least some of your long runs at the same time of day as you'll be running your marathon. This will teach your brain, your metabolism and your gastro-intestinal system to perform as you'll want them to do on race day. Duplicating anticipated weather conditions is often less practicable, but still worth an effort. For example, if you train in a cool-weather climate but will be racing in a warm one, you might wish to do some running indoors on a treadmill (as Christy Gaines did through an Alaskan winter before winning the 2000 U.S. Olympic Trials Marathon in 70-degree heat).
It is very important that you consume a sports drink throughout your long runs. Replenishing lost water, electrolytes and carbohydrate with a sports drink, you will greatly increase your endurance, have a better workout and achieve a more pronounced training effect. Because you will be taking in fluids throughout your marathon, you need to get used to the same practice in your training, just as you need to get used to everything your body will experience in your coming marathon. Wear a fluid belt for all of your long runs, and either carry enough fluid with you to last the entire workout or arrange a brief stop for a fresh bottle halfway through. Drink 4-8 ounces every ten minutes or so (depending on your size, your pace, and the temperature). There are many drinks to choose from. Make sure yours tastes good, does not upset your stomach, and contains 6-8 grams of carbohydrate per ounce. Consider trying one of the newer sports drinks, such as Accelerade, that contain carbohydrate and protein in a 4 to 1 ratio, which has been proven to stimulate a stronger insulin response and deliver glucose to the muscles more quickly, conserve more glycogen, and increase endurance.