Overuse of muscles

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I found this to be an interesting, helpful and enlightening article.

Subject: Overuse of muscles

http://www.aicmt.org/anversa-abstract.htm

Vinci P, Perelli SL, Colazza GB

Abstract of the 9th Annual Symposium of the European Charcot-Marie-Tooth

Consortium, held in Antwerpen, June 30-July 1, 2000

Abstract

The so-called overwork weakness is an overuse syndrome in which muscle fibers

are damaged through exercise, so that the muscles, which undergo overload

either functional or after exercise, increase in weakness.

First observed in post-polio patients, it was also reported in muscular

dystrophies and amyotrophic lateral sclerosis.

We tested three intrinsic muscles in the hands of fifty-one patients affected

with Charcot-Marie-Tooth (CMT) disease type 1 (demyelinating form) and type 2

(axonal form), in order to see if the functional overloading physiologically

acting on the dominant side would cause reduction of strength rather than

strengthening, as happens in normal subjects.

We found out that 99.3 percent of the 153 couples of muscles tested were

weaker or not stronger on the dominant side and that the average difference

of strength for each muscle, measured on the scale MRC, was 0.56 (0.59 in

CMT1 and 0.51 in CMT2).

This phenomenon seems to be unrelated to the time of duration of the disease,

as it is present since the moment the disease starts to affect the hands.

A possible explanation is that overloading exercised in that moment of

vulnerability could cause degeneration of axons that otherwise would be

spared by the disease.

Later in life, if the loss of nerve fibers is severe, a functional

longstanding overload can hasten the physiological aging of the remaining

fibers that had taken part in axonal sprouting with degeneration of the axon

or of some sprouts and consequent appearance of further weakening.

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Kat

Seattle USA