Junk Miles or just Junk Thinking?

I read a lot in the press about junk miles and how bad they are for our training, especially if we are time poor. However, as with a lot of mass market advice, most of what I read has oversimplified the issue to the point of it being just plain Junk Thinking.

So what is the concept of Junk Miles all about?

Simply put, Junk Miles is a concept that has been used to describe training that does not elicit an equivalent or specific physiological response. A specific improvement in fitness.

Training is a game of risk and reward. Every session I plan is considered in the context of the rider concerned, their level of fitness and training history, and their desired outcome in terms of events, races or just an improvement in overall fitness.

Too many training sessions, at too high an intensity, for too long a period time, poses a high risk to the rider’s physical and mental condition. Too few training sessions, at too low an intensity, for too short a period of time, is very low risk, but probably won’t improve anyones fitness.

So what is Junk Miles in the context of this risk reward model of training? Should we all just do medium intensity training a few days a week for 30  minutes at a time?

The most widely vilified training intensity, repeatedly labelled as Junk Miles, is Tempo training. However our risk, reward model would have us do just that. Medium intensity a few days a week for not too long. It’s ‘optimal’ but totally useless as a single mode of training for most people.

Tempo training is highly effective as a first stage strength endurance training intensity, and beyond, if you increase duration to match a specific event demand, such as an Alpine Gran Fondo with many long climbs.

For me Junk Miles cannot be defined by a single mode of training.

Junk Miles is any training that does not address a specific personal limiter to performance or does not improve performance to match a race or event demand. 

Some simplified examples to help illustrate the point.

Club level rider, time poor, who wants to improve times at sportives.

  1. Tempo & Threshold training – not junk
  2. Endurance training – not junk (never junk)
  3. Anaerobic capacity training – junk
  4. Sprint training – junk

CAT 2 Racer, looking to improve dynamic efforts above FTP.

  1. Tempo training – junk
  2. Endurance training – not junk (never junk)
  3. Anaerobic capacity training – not junk
  4. Repeat sprint training – not junk

Ironman Athlete

  1. Tempo & Threshold training – not junk
  2. Endurance training – not junk (never junk)
  3. Anaerobic capacity training – junk
  4. Sprint training – junk

Clearly the model is more complex as we have to factor in where a person is in their training season, but the overall framework and thinking is valid. Assess what you are trying to improve versus the demands of your chosen event or race, and then devise a training plan that maximises the benefit per minute of training. Eliminate Junk Miles by cutting out any training that does not go towards fulfilling a specific objective.

If you have lots of time to train and you want to work on improving your sprint for example, even though you are a sportive rider, then that might be fun, will mix things up and will drive some aerobic gains as well. But if you are tight for training time, why waste your effort and also negatively affect your next specific training session, due to the long recovery time from such an intense sprint session? In this context the sprint session is Junk.

The take away: Ignore everything you read in the press about junk miles but consider what they mean specifically for you as a rider given your abilities and events. Create a ‘Junk Hierarchy’ and prioritise what you need, given the time constraints you have.

I trust that your season is shaping up nicely, and that your fitness and form is where you want it to be coming into the summer? If you have some big events planned for the next few months, and are worried about your training or current condition, then get in touch. We have helped a great number of riders get their training back on track in the final few weeks before a big event, and are here to help you too.