In terms of heart rate, lactate threshold typically occurs at 82 to 91 percent of maximal heart rate or 77 to 88 percent of heart rate reserve in well-trained runners. (Heart rate reserve is your maximal heart rate minus your resting heart rate.) Instructions on finding your maximal heart rate can be found later in this chapter.
Your ability to store glycogen and use fat for fuel tends to improve with the same types of training. Pure endurance training stimulates these adaptations and increases the capillarization of your muscles. For marathoners, the primary type of training to stimulate these adaptations is runs of 90 minutes or longer. Your total training volume, however, also contributes. That’s one reason to include two-a-day workouts and relatively high weekly mileage in your training program.
Long runs are the bread and butter of marathoners. For all marathoners, including the elite, the marathon distance is a formidable challenge. To prepare to race 26.2 miles (42.2 km) at a strong pace, train your body and mind to handle the distance by doing long runs at a reasonable pace.
A long run also provides psychological benefits. By running long, you simulate what your legs and body will go through in the marathon. When your hamstrings tighten 23 miles (37 km) into the race, for example, it helps to have experienced a similar feeling in training – you’ll know you can shorten your stride a few inches, concentrate on maintaining your leg turnover, and keep going. More generally, you’ll have experienced overcoming the sometimes overwhelming desire to do anything but continue to run.
During your long runs, you encounter many of the experiences – good and bad – that await you in the marathon.
No scientific evidence will tell you the best distance for your long runs as you train. However, a clear trade-off exists between running far enough to stimulate physiological adaptations and remaining uninjured. If you regularly do runs longer than 24 miles (39 km), you’ll become strong but slow because you won’t be able to run your other hard workouts at as high a level of quality. You’ll also increase your risk of injury because when your muscles are very fatigued, they lose their ability to absorb impact forces, greatly increasing your risk of muscle strain or tendinitis.
Experience suggests that steadily building your long runs to 21 or 22 miles (34 or 35 km) will maximize your chances of reaching the marathon in top shape while remaining healthy. Experienced marathoners who are not highly injury prone should include one run of 24 miles (39 km) in their preparation.
Long runs shouldn’t be slow jogs during which you just accumulate time on your feet. The appropriate pace for a specific long run depends on the purpose of that run within your training program. The most beneficial intensity range for most of your long runs is 10 to 20 percent slower than your goal marathon race pace. (A few of your long runs should be done at your goal marathon pace – the rationale for these sessions is explained later in this chapter.) If you use a heart monitor, your long-run pace should be roughly in the range of 74 to 84 percent of maximal heart rate or 65 to 78 percent of your heart rate reserve. This will ensure that you’re running with a similar posture and are using similar muscle patterns as when you run at marathon pace.
My experience as a runner and coach indicates that long runs greater than 22 miles (35 km) take much more out of the body than do runs in the range of 20 to 22 miles (32 to 35 km). I occasionally included runs of 27 to 30 miles (43 to 48 km) in my marathon preparations and believe that I ran slower in my marathons because of those efforts.
The only time I really got carried away with long runs was in preparing for the 1985 World Cup Marathon in Hiroshima. The previous year, I had won the Olympic marathon trials in 2:11:43; 3 months later, I placed 11th at the Olympics. I figured that training even harder would bring even greater success. During a 4-week period, I did two very hilly 27-milers and a 30-miler in New Zealand, and I ran them hard, trying to drop my training partners, Kevin Ryan and Chris Pilone.
The World Cup Marathon was on a lightning-fast course. I was very strong but had little speed, and I finished 18th. Although my time of 2:12:28 was satisfactory, the conditions were excellent, and I blew my best opportunity to run 2:10.
– Pete Pfitzinger
If you do long runs much slower than this, you risk being unprepared for the marathon. Slow long runs reinforce poor running style and do a poor job of simulating the demands of the marathon. If you run long runs too fast, of course, you risk leaving your marathon performance out on your training loops because you’ll be too tired for your other important training sessions. Using the suggested intensity range of 10 to 20 percent slower than marathon goal pace, table 1.1 lists suggested long-run paces for a wide range of marathoners.
The first few miles of your long runs can be done slowly, but by 5 miles (8 km) into your long run, your pace should be no more than 20 percent slower than marathon race pace. Gradually increase your pace until you’re running approximately 10 percent slower than marathon race pace during the last 5 miles (8 km) of your long runs. In terms of heart rate, run the first few miles at the low end of the recommended intensity range, and gradually increase your effort until you reach the high end of the range during the last 5 miles (8 km). This makes for an excellent workout and provides a strong stimulus for physiological adaptations. These workouts are difficult enough that you should schedule a recovery day the day before and 1 or 2 days after your long runs.
If you do long runs in this intensity range, a 22-mile (35 km) run will take approximately the same amount of time as your marathon. By running for the length of time you hope to run the marathon, you also provide psychological reinforcement that you can run at a steady pace for that amount of time.
Where the training schedules call for a long run the day after a tune-up race, you should run at a more casual pace. After a Saturday race, your Sunday long run should be at a relaxed pace because you will be tired and have stiff muscles, which increases your likelihood of injury. Start these long runs like a recovery run. If your muscles loosen up as the run progresses, increase the training stimulus by increasing your pace to about 15 to 20 percent slower than marathon race pace.
The total volume of your training also improves your ability to store glycogen and use fat, and it reinforces some of the other positive training adaptations, such as increased capillarization. There is some benefit, therefore, in doing relatively high mileage. The best marathoners in the world train from 110 to 170 miles (177 to 274 km) per week.
More is only better to a point, however. You have a unique individual current mileage limit that is dictated by your biomechanics, past training, injury history, shoes, running surface, diet, and various other life stressors. (For starters, most of those people running 150 miles [241 km] a week don’t commute to a 50-hour-per-week job.) The challenge in pursuing marathoning excellence is to find the mileage range that you can handle without breaking down.
Also, although racing performance improves with increased mileage, the incremental improvement decreases the more mileage you do. In Daniels’ Running Formula (2005), renowned coach and physiologist Jack Daniels, PhD, explains the principle of diminishing return: “Adding more and more mileage to your weekly training does not produce equal percentages of improvement in competitive fitness” (page 13). Increasing from 70 to 90 miles (113 to 145 km) per week, therefore, will not improve performance as much as increasing from 50 to 70 miles (80 to 113 km) per week, but it may produce a benefit nonetheless.