What is meant by Effort or Exertion?

October 15th, 2012 by Phil Weiser No comments »

A sudden flash of insight has challenged my notion of Perceived Effort. For weeks, I had been trying to get ‘my head around’ the role of the motor cortex in the effort required for maintaining running pace, versus no role for a cortex required for the decorticate cat who can still trot once startled into flight. 1, 2

Locomotor signal processing (2008)

Locomotor signal processing Model (2008)

And recently, while I was out running, I started tracking, well, paying attention to, my “Go” signal (see Figure to left from http://www.endurance-education.com/what-limits-endurance/limiting-mechanisms/). Was it there or not?

What I noticed was surprising! While jogging on the level at a slow pace for me, I was doing more thoughts about “Where is the next patch of thick grass for my sore feet?”  than “Push on each stride”; “What is my Rating of Perceived Exertion” was not anywhere in my self-talk. Coming to an upslope, however, to maintain my pace, at first I did have to focus a bit on “Push a little more with each stride”, then once I noticed that I was pushing “hard enough” my self-talk shifted to focus upon running relaxed, and I comfortably crest the little hill. At the end of my workout, against my better judgment, I decided to do an ‘end spurt’ as the English, etc., like to speak of a finish kick; so at a chosen spot, at a bridge across a small river, I thought “PUSH, PUSH” for a few strides to pick up the pace, and then my self-talk switched to “Keep this up” as my legs were pushing the pace fast enough.  My take-home interpretation was that the motor cortex etc. was not all that involved in maintaining gait and was involved in changing pace. Also my working phrase for Effort or Exertion was “Push.”

All of this was sparked first very recently by reading the paper by Klaus Jahn’s group, “Real versus imagined locomotion” 3 where they posit an “executive” versus a “planning” neural network. Second, shortly after that, I read the paper by Ahn & Hogan on “Walking is not like reaching” 4 in which they suggest that locomotor control “is hierarchically organized with a semi-autonomous peripheral oscillator operating under episodic supervisory control”. Wow! Amazing! An executive/supervisor is periodically checking on “How am I doing?” Very interesting….

Now, how to set up the methods and experimental design to explore Effort or Exertion as part of a supervised or supervising neural network? This seems to be daunting, challenging question.

Anyone out there been doing studies on this question?  Please post a comment!


1  Raethjen J, Muthuraman M (2012) Corticomuscular coupling in human locomotion: muscle drive or gait control? J Physiol 590: 3631-2.

2 Grillner S, Wallén P, Saitoh K, Kozlov A, Robertson B (2008) Neural bases of goal-directed locomotion in vertebrates—An overview. Brain Research Reviews 57: 2-12.

3  la Fougère C, Zwergal A, Rominger A, Förster F, Fesl G, Dieterich M, Brandt T, Strupp M, Bartenstein P, Jahn K (2010) Real versus imagined locomotion: A [18F]-FDG PET-fMRI comparison, NeuroImage 50: 1589-1598.

4  Ahn J, Hogan N (2012) Walking Is Not Like Reaching: Evidence from Periodic Mechanical Perturbations. PLoS ONE 7(3): e31767. doi:10.1371/journal.pone.0031767.

Starting to Post again

October 12th, 2012 by Phil Weiser No comments »


After a break to catch up, many of these pages are now proofed and updated. The Limiting Mechanisms section of pages is reorganized, and the introductory page is rewritten. Some of pages are now available for posting.

So check in or subscribe to find out what is happening!

Motor Units, Tired Legs, and Weariness

July 12th, 2010 by Phil Weiser No comments »

Attn: Those curious about Exercise Science

Here are more questions concerning the factors that limit endurance performance that have ‘popped up in my head’ since the 2010 ACSM annual meeting in Baltimore:

  • How are motor units (MUs) with fast twitch (FT), slow twitch (ST), or other muscle fibers recruited and maybe derecruited during first ten minutes of constant, locomotor exercise at the ventilatory threshold?
  • What’s the latest about recruitment and/or derecruitment of various MUs of during the last half of prolonged exercise to exhaustion at the ventilatory threshold?
  • Any psychophysiological differences between individuals with predominantly FT MUs and those with predominantly ST MUs while producing self-selected exercise intensity above the ventilatory threshold?
  • How is MU recruitment monitored by the different regions of the cingulate cortex and other subcortical structures?
  • How is the prefrontal cortex and its subdivisions involved in anticipatory, proscriptive forecasts of possible motor adjustments during the last half of prolonged exercise to exhaustion at the ventilatory threshold?
  • How does the insular cortex, cingulate cortex, etc. determine that an error has occurred while force is being generated during locomotor exercise?
  • How does one become aware of changes in our ‘mental state’ during the last half of prolonged exercise?
  • How similar are the responses of anterior insular cortex (AIC), when experiencing pain as an unpleasant feeling, to the AIC changes when one becomes aware of weariness, i.e., subjective fatigue?
  • What is the mechanism whereby we can talk with ourselves and others, i.e., vocalize, about being weary, as having subjective fatigue symptoms?

More questions associated with an ACSM presentation examining cool-down after exercise session can be found in the post: “Cool Down and Enjoy”

Comments anyone? Any suggestions for pertinent reviews? Any thoughts or personal insights? Additional related questions?

Cool down and Enjoy

June 21st, 2010 by Phil Weiser No comments »

What helps people enjoy exercising?

Well, Soundarapandian, Ekkekakis, & Welch (2010) wowed me with a really important answer to this question via an attention getting slide presentation. That happened on Friday, June 4th, at the American College of Sports Medicine annual meeting in Baltimore. CLICK TO READ MORE

Reviews about Exertion Pain during Cycling

May 28th, 2010 by Phil Weiser No comments »


Today the REAL POST (Part 1) about Coping with Pain during Cycling is up. (Read this post)

And For The Curious, the Part 1 Post is continued as the First Review today: What describes Exertion Pain during cycling? (Read this review)


Cyclists’ Cognitive Strategies for Coping with Pain (Part 1)

May 2nd, 2010 by Phil Weiser No comments »

“Wow! Amazing!!” I said one day. This was on the day I discovered an article entitled entitled “A naturalistic investigation of former Olympic cyclists’ cognitive strategies for coping with exertional pain during performance”. It was by Jeffery Kress & Traci Statler detailing a fascinating study of nine former Olympic cyclists and was published in 2007 by the Journal of Sports Behavior (1).

What was ‘pain’ for the cyclists? How did they deal with this pain?

This review blog consists of 4 posts. This 1st post will discuss methods and the cyclists’ personal description of pain. The 2nd post will focus on their perceptual and temporal modification of pain. Then the blog’s 3rd and 4th posts will discuss preparing for and ways of handling pain.   CLICK TO READ MORE