An easy run is really just that. Reasons can be various depending on your training schedule. In order to finish a full marathon, runners need to put in a certain amount of time running to condition their muscles.
An easy-run is meant to mean running at a comfortable pace which can be maintained for a longer time without much effort. Being able to hold a conversation with a fellow runner is a good measurement. When you're out of breath, huffing and puffing than you're going too fast to call it an easy run. To throw in a few numbers, running 6 to 10 percent slower than your marathon pace or adding 20 to 30 seconds to your marathon race pace will give you your easy run pace.
When to run and easy run
Another word for easy runs could be a conditioning run. The conditioning run can be ran at the same pace as the easy run with the purpose of increasing the blood flow through the body and to the muscles in order to increase the supply of oxygen and other essential nutrition. A conditioning run can be the next day after an interval run, Vo2 max workout, lactate threshold workout, tempo run, Fartlek interval training, and a tempo run. This is just to keep building the amount of weekly mileage without putting MORE strain on the body when it is already exhausted after a hard workout. By running an easy run the body will learn how it can recover faster and that it must recover faster.
Benefits of Easy Runs
A big benefit of easy runs is that they add to the total amount you run during the week. But because of the slow pace there is minimal damage to tissue and muscles so recovery is required on a nutritional level only. Our body is trained to refuel faster in order to be able to handle the next workout. When our body can recover faster from running than we can do a higher volume of training and train harder than if it would take a long time for our body to recovery from every run. In order to prepare for a full marathon race you need to put in many miles to build your aerobic fitness, and your muscular and skeletal strength. Conditioning our body for the long strain of a P.B. marathon race.
Running comfortably at an easy pace trains our body to burn fat more efficiently. Especially at the end of a marathon race we might run out of carbohydrates to burn and our body switches to burning fat. Fat doesn't provide as much energy as carbs do so we might have to slow down. Also, burning fat requires more oxygen so we have to breathe harder to keep the same pace as when burning carbs. For those who are looking to loose a few pounds, running at slow pace will burn more unwanted fat then running hard.
Easy Runs and Long Runs
Long runs are done at the same pace or even little slower than the easy runs. Adding the miles of your easy runs and long runs of one week should give you about 80 to 90 percent of your total weekly mileage. The other 10 to 20 percent can be used for Vo2 max training, lactate threshold training, or speed and form training