All athletes question the easy workout days. In my opinion they are just as important as your hard stuff! But unfortunately they are brushed off and not given the respect they deserve. There are both mental and physical benefits from these workouts. They’re all the other miles–not the tempos or track repeats or long runs. They’re the entries in your training log that make up a large percentage of your weekly mileage total, but with which you don’t bother to record much data: Simply an “8” or a “20” or “1000” or “around the hood” suffice to remind you what you did that day.
The easy day is the Rodney Dangerfield of distance training: It receives precious little respect. Some athletes might even use the term “junk miles”. Why do we do them? This is why plain and simple: easy training, provides fundamental adaptations.
Here are the physical benefits, the facts. On easy days, you’re using mostly slow-twitch muscle fibers. They have a higher density of mitochondria, high levels of aerobic enzymes and greater capillary density than fast-twitch fibers, which are more involved in higher-intensity training. On easy days, you increase mitochondria and capillaries and blood flow to those muscles, so they’re better able to utilize oxygen. Without that, you can’t do the intense training.
All athletes, and especially beginners and those coming back from injury, benefit from the cardiovascular and muscular-structural development that easy training promotes. The base fitness an athlete puts down through a preponderance of easy workouts enables the athlete to safely progress to other types of training.
Seasoned athletes also need easy days in order to maintain hard-earned aerobic fitness and make continual gains in all areas of training. Of course, competitive athletes are interested in moving efficiently at race paces, this is the primary reason for training at a variety of intensities. Slow training allows for modest gains in efficiency of movement.
Here’s what I consider to be the most important factor in the easy workout. All athletes need to recover from the hard days. An athlete should be able to achieve a training effect every day, to me recovery is a training effect. It may not feel like it but the underlying mental rest needed to keep improving is essential to success. It’s during recovery that adaptations from the hard training take place. If an athlete doesn’t recover, the body is not going to adapt, and you’ll either continue digging a hole for yourself or get injured. So take your easy day and your rest days, they may not be registered on your garmin or the fastest recorded on Strava, but they count!