All in your mind, even with weights.....

I've previously pointed to the research of Dr Marcora with his psychobiological theories of fatigue.  I also highlighted Noakes paper on the role of the brain in fatigue. 

All that research seemed to focus on endurance exercise but it was interesting to see Alex point to new research that indicates that there are similar ideas at play with respect to lifting weights. 

What I thought was neat about the study was the distinction between "peripheral" and "central" fatigue: the former is the reduced ability of your muscle itself to contract, and the latter is a reduction in the signal from your brain to your muscle demanding contraction. If you pick up a heavy (above critical torque) dumbbell and lift it until you can't anymore, the limiting factor appears to be peripheral fatigue. Your muscles are simply no longer capable of contracting powerfully enough to lift the weight. In contrast, if you lift a lighter (below critical torque) dumbbell to failure, your muscles themselves fatigue to a much lesser extent, suggesting that fatigue somewhere in your brain or central nervous system is the problem.

The study is Distinct profiles of neuromuscular fatigue during muscle contractions below and above the critical torque in humans.

Noakes on Fatigue - it is all in the brain....

A few weeks ago I pointed to the ideas of Samuele Marcora and his psycholbiological model of fatigue.  I also recently had an articule published in a UK hillwalking magazine which looked at his ideas.

I just noticed an review paper - the whole pdf is available - by the prominent Exercise Scientist Tim Noakes around these ideas:

Fatigue is a Brain-Derived Emotion that Regulates the Exercise Behavior to Ensure the Protection of Whole Body Homeostasis

The ideas are somewhat different from those of Marcora, who sees motivation as much more important, but the key is still the brain, not the muscles or cardiovascular system:

The model predicts that attempts to understand fatigue and to explain superior human athletic performance purely on the basis of the body's known physiological and metabolic responses to exercise must fail since subconscious and conscious mental decisions made by winners and losers, in both training and competition, are the ultimate determinants of both fatigue and athletic performance.

Worth reading.

The nature of fatigue

I've been doing some reading for an article that I am writing on the nature of fatigue and the Brain's role in exhaustion.

Once the article has been published I'll post some of it here, but for now I just wanted to point to the work of Samuele Marcora

There is a good interview with him here - Perception is everything

and his key studies are 

·      The limit to - Marcora SM, Staiano W. Eur J Appl Physiol. 2010 Jul;109(4):763-70. Epub 2010 Mar 11.

·      Mental fatigueMarcora SM, Staiano W, Manning V. J Appl Physiol. 2009 Mar;106(3):857-64. Epub 2009 Jan 8.

·      The face of fatigue de Morree HM, Marcora SM. Biol Psychol. 2010 Dec;85(3):377-82. Epub 2010 Sep 9.

In his model, fatigue is a psychological issue, not a physical one.  When the perception of effort excedes the reward from that effort we give up.  The key is in modifying our perceptions.

Fatigue and Coordination

Yesterday I pointed to a study that said that muscular fatigue impairs coordination.  As usual I just did a hit and run post - highlighting the study and then letting you make your own conclusions.

Todd Hargrove picked it up and made some excellent points  (Todd always makes excellent points!)

1. To optimize motor learning, minimize fatigue

2. Skill under fatigue may be a skill in itself

3. To avoid skill deterioration from fatigue, work on your fitness



  Read the detail in his post.

Skills - practice when you are not tired

The Effect of Muscle Fatigue on Position Sense in an Upper Limb Multi-joint Task

When your muscles are tired you are less able to sense where your limbs are in space.  Think of the implications of this for complex skills.  Trying to use complex skills as strengthening moves is risky.

That is why I favour big simple movements with low skill levels.  Skill conditioning is something different.  I apply this in Hillfit

Using Lasers to benefit muscle recovery?

I saw this abstract and had to do some Google -fu to find out what was going on!  

Apparently you can reduce post exercise muscle fatigue but exposing the tissue to low intensity lasers......