Friday, December 18, 2015

Mixed Workouts & Why Single Focus Is Often Better

VO2 Max Repeats

If you are a regular reader of this blog or have read much of the information on my websites, you will know that I believe all training come down to the stress and recover principle.  It is simply the basis behind all physical training.  We must stress our body in a certain way, then allow it to recover and when it does it will be better adapted to that stress.

When we look at the stress workouts we do to cover the stress side of stress and recover, it is important to clearly define what we are after. As you may have read before, here is how I define our goal in doing a stress workout:

Stress Workout:  These are running workouts in which we significantly stress a system or systems of the body in order to produce a targeted adaptation so as to improve certain aspects of our fitness.  Our goal is to do sufficient and specific enough work in order to elicit the adaptation we are seeking, while still being able to recover from that work relatively quickly so that we can quickly target another adaptation.  To accomplish this we want to finish our stress workouts feeling like we have worked very hard, but not having all out raced out efforts.  In order to keep the training process moving forward and to be able to target all necessary systems with adaptation on a regular basis, a stress workout should be able to be recovered from with 1-3 easy/recovery days.

There is 1 specific line in this definition that I want to focus on today:
"Our goal is to do sufficient and specific enough work in order to elicit the adaptation we are seeking"

This means that we must know what adaptation we are seeking, and then know the type of work to do to achieve it and then how much work is sufficient and specific enough to elicit that adaptation. Think about that, that is no small hurdle.

Mixed Workouts

Most of us have seen and done mixed use workouts before.  Those are workouts that consists of work at multiple different intensities and works multiple systems in 1 workout.  An example may be a short tempo run to work our lactate threshold followed by a some speed intervals to work VO2 Max.  Or a pyramid workout that includes some intervals are at lactate threshold, groove, VO2 max and ever fast interval paces.

These mixed use workouts are popular among some coaches because they sound cool and complex and there are countless variations that can be used.  And they are popular among some runners because they are fun and interesting to do with changes in speeds and intensities that change things up several times during the workout.

But the problem with these mixed use workouts is that they often fail to meet the hurdle stated above, they are not "sufficient enough in order to elicit the adaptation we are seeking." They simply don't allow us to do enough specific work in any one system to elicit a desired new adaptation. Rather what they are good at doing is allowing us to do enough work in multiple areas to maintain existing adaptations.

Lets look at an example to help us see what I am talking about.  Here are 3 different workout possibilities for one of our stress days:

Workout #1:  30 minute LT Tempo Run
Workout #2:  8 x 3:00 VO2 Max Repeats
Workout #3:  15 minute LT Tempo Run + 4 x 3:00 VO2 Max Repeats

Workout #1 should provides us with sufficient and specific enough work to elicit a new adaptation which improves our lactate threshold

Workout #2 should provide us with a sufficient and specific enough work to elicit a new adaptation which improves our VO2 Max

Workouts #3 likely does not provide us sufficient and specific enough work to elicit a new adaptation in either lactate threshold or VO2 Max but likely does provide sufficient enough work in each to maintain existing adaptations.

Single Focus vs. Mixed Use - When To Use Each

So the question then is when is it best to use a simple single focus stress workout and when to use a mixed use workout.  Here is what I recommend:

The vast majority of your stress workouts should be single system focused stress workouts, those are the best way to elicit new adaptations and improvements in fitness.  This doesn't mean you can not change up how you attack that system within the workout (such as doing a tempo run followed by tempo intervals all targeting LT or AT or doing a cut-down workout or pyramid intervals all at the same pace/system target) but the focus of the work remains on the same system.  This is simply the best way to consistently improve our fitness by eliciting desired adaptations in targeted systems.

Use mixed use workout in situations in which you need to touch base on several systems in order to maintain existing adaptations and prevent backslide in those areas. Often this will be late in a training cycle (think Specific Phase) when you can not afford to spend entire workouts working systems that aren't primary to the goal race distance but you need to do some work in those areas in order to prevent backslide in those areas which could impact primary focus fitness.  Another time I will often use a mixed use workout is early on race week where I am not after new adaptations but rather just want to touch base on a few areas to make sure existing adaptations are shore up.


As always, in your training carefully plan out what systems you need to work on and improve and then design workouts that are sufficient and specific enough to elicit the adaptations you are seeking.  But never forget that without sufficient recovery afterwards, those adaptations can not and will not happen.  Recovery is just as critical as the stress, be sure to honor each.

Happy Running.

Coach Mark Hadley


  1. Shall look out for your recovery articles.

    How does the body recover. What are the processes involved.

  2. Great post Mark! I had a doubt about the exact thing the other day! I think We could benefit a lot mentally doing the mixed workouts! Cheers!