Marathon training does, indeed, require a lot of running, but you should not run every day!
Before I get into some of the specific running workouts for marathon training, I want to talk a bit about cross-training.
There is no magic to cross-training. Cross-training is simply doing some exercise other than running.
Swimming, biking, Pilates, yoga, situps, pushups, planks, squats, upper-body weight lifting, etc, are all great examples of cross-training.
The purpose of cross-training is two-fold. First, it gives your legs and feet a chance to rest and recover.
The marathon training schedule I use, the YCGTD Marathon Training Plan, only has 3 runs per week, but they are very intense and specific types of running workouts (which I will cover in later chapters), and my 50-year-old body needs the recovery time in between runs. Cross-training on the non-running days has been a huge help to me while I recover.
What most beginner athletes do not understand is that strength is actually created during the rest/recovery period rather than the actual training. Recovery is crucial to building strength. This is why you do not want to run every day. You need to give your feet and legs time to recover. Plus, you need to strengthen other parts of your body—marathon run requires your entire body to be in shape, not just your legs!
The second purpose of cross-training is to strengthen other muscle groups that indirectly support your running. For example, swimming helps improve cardio and upper body strength, both of which are important to running. Pilates, yoga, planks, and simple push-ups and sit-ups improve your core strength which you will need for endurance and posture on those long runs.
While I have mentioned biking as a great cross-training exercise, I want you to be careful if you use a bike. Remember that the primary goal of cross-training is to give your legs a break while they recover from running. Biking, whether on a real bike or on a stationary bike, should be done lightly, not as an aggressive workout.
Let me say a word about treadmills. Treadmills can be great as a way to get in a run if the weather is bad, but there is a temptation to use treadmills too often out of convenience, especially in extra cold or extra hot weather conditions. There is, however, no substitute for road running. Your marathon will not be run on a treadmill; it will be run on the road!
The other problem is that people do not use treadmills properly. They think that if they set the treadmill to the same pace they would be running on the road that they are training at that pace. That is just not true. You need to set a treadmill at a 1.5% incline just to simulate the equivalent effort of running on perfectly flat ground. Running on the road has hills, uneven surfaces, varying wind and other conditions that you do not get on a treadmill. So, while a treadmill can be helpful, only use it as a very rare substitute for running outside on the road.
As I talked about in the previous chapter, you might need to change our training schedule around if the weather is bad. Instead of just skipping a workout day altogether, cross-training is a great way to stay on schedule and maintain the momentum of your training, which is all part of the mental conditioning.
Cross-training is also a great way to stay in shape and try to stay on your training schedule if you suffer an injury. If you twist an ankle or develop shin splints or some other kind of injury, do not just drop out of training completely. Use cross-training and other low-impact leg exercises to maintain conditioning while you recover.