Junk Miles: What are they and are they bad for you?
You've probably heard people use the term 'Junk Miles'. It's a term I've used and I've heard the term used in different ways and wanted to try to add some clarification to the definition and discuss whether or not they are bad for you and should be avoided.
Some people have used the term Junk Miles to describe any riding that is done at slow speeds. I don't like this description because there are many reasons why this kind of riding is not 'junky'. More than once I've been criticized for using the term and have had people tell me that all miles are good and there is no such thing as junk miles. If your intent is to ride at your chosen pace and enjoy yourself, I can't disagree. So, here's my definition: "Junk Miles are those miles ridden at a pace fast enough to cause fatigue but not fast enough to cause a training effect" Obviously, from this definition, I am referring to training. If you are not riding your bike to train and to get faster, then the term 'junk miles' does not apply to you. If you are a recreational cyclist and just enjoy riding for the joy of it, then all miles are good.
When I use the term Junk Miles, I am referring to riding that is done which does not help you improve
but makes you more fatigued and gets in the way of recovery. Another way to say it is: Junk miles are recovery miles that are ridden too hard. Let's take an example: Let's say you are training for a race and you have done one day of anaerobic intervals and the next day you did some hill repeats. On the third day you are due for a recovery day. Active recovery is where you get out and spin on your bike so move your legs but do not ride hard enough to do more harm to your already tired legs. You should feel very little resistance on your pedals and spin at a high cadence. This is what coaches refer to as Zone 1. Now here's where junk miles come in. You start out with good intentions of spinning easily in a low gear. Up ahead you see another rider and your competitive juices kick in. You start increasing your speed to see if you can catch that person. Pretty soon you are riding at your endurance (Zone 2) or tempo (Zone 3) pace. You may even stand and charge up a hill. Perhaps you even catch that rider. Now what? You have to save face and not slow down, even though you know you should, so you keep riding hard and put distance between the two of you. Your active recovery ride has just become another training ride. Three things have just happened: 1) You blew your recovery ride and went way beyond a recovery effect 2) You tired your legs out even more instead of letting them recover and 3) You pushed hard, but not hard enough to improve either your leg strength or cardiovascular fitness. The Tempo pace is usually what gets people in trouble. This pace is faster than what you usually ride on longer endurance rides, but slower than what you would do during intervals. It's that in-between zone often called 'No Man's Land'. Riding at tempo pace does have it's place but should not be substituted for recovery rides.
Typically following a recovery day is another hard training day, so if you stick to your plan, the next day you are out there trying to train hard but you probably won't have a very good ride. That's because you didn't recover on your recovery day and still have residual fatigue. So now you've compromised your intense day of training. This is where I apply the term junk miles - when you push hard enough to prevent recovery but not hard enough to stimulate further improvement. Plus you've compromised the following quality workout.
You would have been much better off all the way around if you kept your recovery day easy. Let that rider go up the road.
Know that doing these slow easy recovery miles is just as important as the fast, hard training miles. Don't worry about what others think about you. Maybe you are all decked out in your racing kit and don't want to be seen going slowly by recreational, or worse yet, by other racers. Stick to your guns and ride slowly. By riding slowly you are recovering so you can ride faster tomorrow.
This definition of junk miles goes along with another one of my favorite sayings: "Every ride should have a purpose." Note this doesn't say every ride should be hard or fast. If your purpose is to do hard anaerobic intervals and you do that, you've accomplished your objective. If it is to ride around the neighborhood looking at the changing leaves and you do that, then you've also accomplished your purpose. But pay particular attention to those days where you intentionally want to go easy and allow your legs to recover. If you ride too hard, you've missed your objective and ridden junk miles. So using my definition of Junk Miles, if you ride hard enough to either add fatigue or prevent recovery but not hard enough to improve, then you've done junk miles. It would have been better to ride more easily. There is a time and place for recovery or slow riding. Don't junk them up by overdoing it.
All the best in training!
David Ertl is a USA Cycling Level 1 (Elite) Coach and NSCA Certified Personal Trainer. He coaches individuals interested in improving on their current cycling ability, whatever level that may be. He also provides cycling training plans and ebooks at his website: www.CyclesportCoaching.com
He can be contacted at Coach@CyclesportCoaching.com
Download this article as a .pdf file