The long run is one of the most crucial parts of your training preparation for a marathon, as it will ensure you can run the distance on race day. But crucially, the importance is on the quality of your training not the quantity.
SO HOW FAR SHOULD YOU RUN IN TRAINING?
At Mbition we believe you shouldn’t run for longer than 20 miles in your marathon training. A 21 mile run (or longer) can be a great confidence booster, but from a coach’s perspective they don’t make much sense!
Most runners training for the marathon are averaging anywhere from 9 minutes to 13 minutes per mile on their long runs (3:45 to 5:30 hour finishing time). At a pace of 10 mins per mile, a runner will take roughly 3 hours and 30 mins to finish a 21 mile run.
The majority of the physiological stimuli of a long run occurs between 1 hour 30 minutes and 2 hours 30 mins. In fact, running for 3 hours plus starts to have a negative affect as your muscles will start to break down and fatigue will set in, which in turn leads to a significant delay in recovery time. This delay will affect your ability to complete other important workouts in your plan, and the quality of your training will start to diminish.
Running long distances are tiring, repetitive and will place a significant amount of load on your body - two and a half times your bodyweight to be exact. So it’s not surprising that the chance of injury also increases as your mileage ramps up.
To sum up, it’s not really about the mileage, it’s about the time you run for as you’re not going to get many training benefits after running for 3 hours. It’s best to bolster shorter long runs with other quality training sessions such as tempo, steady and speed workouts throughout your training week. This will simulate the fatigue you’ll experience at the end of the race, but significantly reduce your risk of injury and stress you place on your body.