Perhaps the most basic Principle of Training is “Specificity” which simply states that your body responds very specifically to the types of training that you do. If you do not prepare your body for the demands of racing, then you cannot expect it to be ready to handle those demands. For marathoners, if you do not train for the specific conditions your next marathon will throw at you, then it is very likely that you will have problems on marathon day.
Among the important aspects that are easy to overlook in your marathon preparation are the unforgiving hardness of the road, the marathon’s terrain, and the appropriateness of the shoes you will wear on race day. Let’s look at each of these factors:
26.2 Miles of Pavement
The major marathons in the world are run exclusively on paved roads. That means 26.2 miles of repetitive pounding on a hard, uniform surface. A marathon represents over 25,000 steps landing with a force of three to four times your bodyweight. To successfully run the marathon, your body must be prepared to handle this abuse.
Anecdotally, it appears that too little road training makes it more likely that you will get in trouble during the second half of the marathon. For example, in discussing an Olympic 10K runner’s relatively poor performance in the 2002 Chicago Marathon, he revealed that he does 90% of his running off-road, and that his legs felt progressively more beat up with each successive mile of the marathon. Despite putting in high mileage and doing a respectable number of long runs, his legs just weren’t up to the task. After running the first 20 miles at 2:13 pace, this world-class runner’s sore muscles forced him to slow dramatically over the last few miles of the course.
Why do You Need to Hit the Roads?
Although the differences between running on trails or a treadmill versus the roads have not been studied extensively, the scientific literature provides insight into why it may be beneficial to prepare your legs for the specific task of running 26.2 miles on the road. Studies have shown that when you run on a hard surface your achilles tendon and foot work together to conserve energy by returning stored elastic energy into your next stride. When you run on soft surfaces, however, the re-utilization of stored elastic energy from your achilles tendon is reduced because the softer surface absorbs more of the energy. Biomechanist Liz Bradshaw, PhD, explains, “This difference in the action of the achilles tendon and calf muscles makes running on soft surfaces less specific to the requirements of road racing.”
Clearly, you need to do a portion of your training on the road. Yet you must also get to the starting line uninjured, and as you increase your mileage on the roads (or worse yet, sidewalks), your risk of injuries to your feet, legs and back also increases. What is the optimal balance between doing enough road mileage to be ready for the marathon while keeping your injury risk at an acceptable level?
To toughen your legs for the pavement, you should do at least 30 miles per week on the road during the last 10 weeks before the marathon. Depending on your weekly mileage, this may represent as little as 25 percent or as much as 75 percent of your total running. That should be enough to prepare your legs for the marathon. Ideally, you would do most of your other training on softer surfaces to reduce your likelihood of injury.
I also recommend that you do a minimum of five long runs primarily on the road during the last 10 weeks of training to ensure your body is primed to handle the repetitive stress of the marathon. At least two of those runs should be over 20 miles. If you are an off-road fanatic, you could do the first hour of your long runs on softer surfaces, and then hit the road for the last hour or so. The objective is for your muscles and tendons to get used to the pounding of the road when they are becoming fatigued.
While some courses, like the New York City Marathon, include significant uphills and downhills, others are almost dead flat. Both types of courses require specific preparation. A pancake flat marathon uses your muscles in exactly the same way over the same range of motion for thousands of strides. This lack of variety enhances fatigue as your hamstrings and calf muscles and quadriceps repeat the same cycle over and over again. To prepare optimally for a flat marathon, you should do most of your long runs over similarly flat terrain.
While running uphill may slow you down a bit it is the downhills in courses like the Boston Marathon that can destroy you. When running downhill, your muscles work eccentrically to resist the force of gravity, which causes microscopic muscle damage, inflammation and our old friend delayed-onset muscle soreness. The good news is that training on downhills has a protective effect that reduces subsequent damage and muscle soreness.
Rather than doing hill repeats in which the downhills will make you incredibly sore and could leave you injured, practice hill running by training over rolling terrain. The best simulation for a hilly marathon course is to incorporate a similar sequence of hills into your long runs. This was one of Bill Rodgers’ secrets for winning both the Boston and New York City Marathons year-after-year-he designed his training to prepare for the ups and downs on those courses.
Marathon Shoe Selection
Finally, if you plan on wearing racing shoes in the marathon, make sure you know in advance whether they will provide the support you need over 26.2 miles. To try out your shoes for both sustained speed and long distance, you should wear them in a half-marathon and a long run before the marathon. One factor to consider is that racing shoes almost always have a substantially lower heel lift than training shoes. If your calf muscles are not used to the lower heel lift you can be pretty sure they will rebel when you ask them to work over an increased range of motion for 26.2 miles. Generally, a more supportive, but still reasonably lightweight shoe will be well worth the extra couple of ounces during the second half of your marathon.
(This column originally appeared in Running Times Magazine.)