An extreme HIIT study protocol. Courtesy Flockart

Note : The lead author of the paper Dr. Mikael Flockhart and I had a conversation regarding some of the open questions surrounding the study design. I’ve paraphrased his comments in the “Appendix” section at the bottom of the post for those interested.

When looked at the extremes, too little exercise and too much exercise are both known to be problematic. Its easy to show what happens with lack of exercise. But at the upper end of that scale, the waters are murkier.

Its an open question “how much” intensity and volume is tolerable before the body simply shuts down…

I reviewed a new paper in Redox Biology which provide several arguments why mitochondrial health is crucial for the general anti-viral host defense. Endurance athletes and coaches will recognize mitochondria as the main center of cellular energy generation during aerobic exercise.

The salient points highlighted by these researchers from Institute of Sport Sciences at University of Lausanne are the following :

1. The center piece of the mitochondrial anti-viral machinery has been demonstrated to depend on mitochondrial membrane potential which is responsible for ATP production. If the virus modulates that potential, mitochondria is less capable in antiviral defense.

2. Defects…

Athletes know what fatigue is. We seem to have an intrinsically built antenna for sensing how we feel before and after a workout.

But ask anyone to give a short elevator speech explanation of fatigue, and even the mighty coach will wince.

Western sports science came up with a simple mathematical relation from the so-called impulse-response model :

Form = Fitness — Fatigue

This black-box idea of “fatigue” looks even simpler than applying Einstein’s E = Mc², as everything is nicely linear here, calculable and attributable to one thing — exercise activity.

But whereas E= Mc² has an accuracy of…

As more people train and compete virtually indoors , all the nasty stuff is the air around you could interfere with getting a good workout.

Now we know that open flame cooking, small congested interiors, lack of ventilation and high ambient air pollution outdoors can all cause carbon dioxide buildup. What most of us don’t realize is the extent of the problem.

In discussing this with someone who uses a highly accurate and expensive fixed monitoring station at home that samples the air every minute, I have come to understand that CO2 levels near the spot where he has set…

Confusion exists among athletes when it comes to training changes when sports events are postponed due to on-going pandemic. The new race dates can be several months into the future. This is the state of affairs now in many parts of the world.

The story is a bit like this. You’ve given blood and sweat for more than 10–12 weeks on the knowledge that event will be on X date, but with 1week to go, you’re notified that X date is moved to Y date, only 5 months away.

Its a catch-22. If you stop training altogether, you slowly but…

“Easy Days Hard, Hard Days Easy”

Tired all the time

An often committed mistake of endurance athletes in training is going hard on easy days and as a consequence, unable to go hard on hard days when the plan calls for it.

In other words, nearly every workout in the week becomes hard with little to no differentiation. High monotony.

This is a classic training error that just piles on a bunch of stress and offers little room for adaptation. Even a study published just recently this month (which I will review soon) reveals that “excessive exercise intensity” does not bode well for mitochondrial function in healthy volunteers.

The issue…

What’s the best way to pace a race effort? “It depends”.

Theory postulates that attempting a course with the highest steady state effort one can sustain without dipping too much into the extreme regions of the physiological intensity spectrum is the “optimal” way to pace.

But with that end in mind, all pacing profiles should divert to a mindless run at constant speed. The issue is that mathematically derived optimal pacing is still “open-loop”. Theory and practice differ and real world athletes tend to differ in their pacing approaches because humans are “closed loop” organisms.

Wouldn’t it be nice to inspect some real world data to see how people pace?


A unique research study published this month looked into 41 marathon veterans who ran sub3hr performances for 5 straight decades. This is a rare population of athletes, since only around 4% of marathoners achieve sub-3 hour timings according to years of data from worldwide marathon statistics (

The statistical findings are startling. Despite advancing age, performance degradation in these runners was only +1 min 29s per year, OR an average decrease in running speed of 0.67% per year.

What is the significance of this finding?

Commonly it’s held in the running community that an age related performance decline of 7–8%…

Ron George

Independently reviewing the curious science behind endurance performance since the late 2000s. Find me on Twitter

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