Episode Details

Modern, elite endurance athletes perform ~80% of their training at low intensity and ~20% at high-intensity.

It has not always been this way. This training intensity distribution appears to have increased in popularity each decade. The % of training at low intensity has increased.

In the offseason, there’s almost no Zone 3 or above training.
Pre-competition it’s a little more.
Competition it’s a little more.
But even during the competition period, on average, it’s still 80% low intensity. 

Defining the terms

Low Intensity = Zone 1, e.g. <2 mM blood lactate, long slow distance, stable blood lactate, physiologically sustainable, primarily aerobic energy production

Moderate Intensity = Zone 2, right below lactate threshold, e.g. 4 mM blood lactate, “threshold training,” can be continuous or intervals

High Intensity = Zone 3+, e.g. >4 mM blood lactate, intervals, physiologically unsustainable, greater contribution of anaerobic energy production

Two high intensity training sessions per week suffice to induce adaptations for performance.
 
CrossFit is supramaximal in intensity – nearly every task you do is physiologically unsustainable.

~50/50 anaerobic and aerobic energy production

The % 1RM of the contractions you have to repeat is very, very high compared to endurance sports. This is why strength is so important. So before you even think about how to best condition for CrossFit, you’ve got to be really, really strong. 

Once you are really, really strong, then you have to train extensively because the competition is extensive.

That’s where this sort of approach comes into play.

1) Lots of direct Zone 1 work that is concentric-based and targets the quads

2) 2 high intensity (Zone 3+ training, >4 mmol lactate) sessions per week suffice to induce adaptations for performance. Mixed or cyclical.

3) Reduce the RPE with which you do your conditioning.

4) Use machines to replicate the patterns of movement but remove all eccentric loading. Too much eccentrics will result in too much tissue damage. Has to be concentric based.

These 4 machines cover each movement pattern for CrossFit:

Rowing – knee extension, shoulder extension, scapular retraction, hip extension (squat, bend, pull)
Biking – knee extension – (squat, push)
Skiing – shoulder extension, elbow extension, core and hip flexion (core, push)
Stairmaster – knee and hip extension (lunge)

Final thought:

The CrossFit experiment is, what if we just do high intensity every day?

We don’t really know what happens. Other than that people quit after 5 years.

There must be something going on psychologically and/or physiologically with higher intensity training that makes it unsustainable.

https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2015.00295/full