Sense of effort during a fatiguing exercise protocol in chronic fatigue syndrome (Wallman/Sacco, 07)

[Dolphin]

Sense of effort during a fatiguing exercise protocol in chronic fatigue syndrome.

Res Sports Med. 2007 Jan-Mar;15(1):47-59.

Wallman KE, Sacco P.

Source
School of Human Movement & Exercise Science, The University of Western Australia, Crawley, Western Australia. kwallman@cyllene.uwa.edu.au

Abstract*

The purpose of this study was to determine whether chronic fatigue syndrome (CFS) subjects would produce greater force production in their matching limb during a fatiguing contralateral limb-matching task of the elbow flexors, compared with healthy, matched controls.

Eight CFS subjects and 8 healthy, matched control subjects participated in a fatiguing task that consisted of intermittent submaximal contractions (30% maximal voluntary contraction) of the nondominant arm performed over a 45 min duration.

Each minute, the subject attempted to match the force of the nondominant arm with their dominant arm (without visual feedback for the dominant arm).

Results showed that average matching force and ratings of perceived effort values were significantly higher in the CFS group during the fatiguing task (P = 0.04, P = 0.02, respectively).

This study demonstrated objectively that CFS subjects experienced a greater sense of effort in the elbow flexors while performing a fatiguing task.
PMID: 17365951 [PubMed - indexed for MEDLINE]

*I gave each sentence its own paragraph

 

[Dolphin]

This is from the introduction:

McCloskey (1978) notes that a contralateral limb matching task provides an objective indicator for perceived heaviness, as changes in effort sensation are reflected by the match of the contralateral/nonreference limb. Results consistently have demonstrated that as fatigue develops, subjects tend to overestimate the force when attempting to match a sustained isometric contraction of the reference arm (Cafarelli 1992; Gandevia 1997; Jones 1995).

The authors in the discussion section discuss various possibilities. However, I'm not sure if they explicitly mention this i.e. that what they could have found is that the CFS patients found the test more fatiguing. It is the case that the CFS patients had consistently higher perceptions of effort through the test, such that:

during the last 10 minutes of the protocol, all but one CFS subject classified the final contractions as being either “almost maximal” or “maximal,” while average scores for the control group rated the contractions over the same time period as being “very strong.”