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History of physiology; In particular, I found chaper 2 fascinating in its
historical presentation of the science of muscle physiology, 

Excerpts

A.V. Hill: muscle studies pioneer, Nobel 1922
Served as a member of the British Parliament from 1940 to 1945 and as a
scientific advisor to India.
during World War II, Hill was a leading figure in the Academic Assistance
Council, which helped Jewish scientists fleeing Nazi Germany to relocate in
the West.

Beginning in 1910, A. V. Hill performed careful experiments on the time
course of heat production in isolated frog muscle. His research paralleled
that of the German biochemist Otto Meyerhof, who measured the changes in
muscle glycogen and lactate during contractions and recovery. For their work
in discovering the distinction between aerobic and anaerobic metabolism, Hill
and Meyerhof were jointly awarded the 1922 Nobel Prize for Physiology or
Medicine. Because of Hill's interest in athletics, he sought to apply the
concepts discovered in isolated frog muscle to the exercising human. Hill and
his colleagues made measurements of O2 consumption on themselves and other
subjects running around an 85-m grass track. In the process of this work,
they defined the terms "maximum O2 intake," "O2 requirement," and "steady
state of exercise."

Chapter 2: Neuromuscular system: Alam McComas

Those who ate meat could not have helped noticing that some muscles or parts
of of muscles were darker than others...  In 1665, Nicholas Stensen stated:
    Middle parts of the motor fibers [muscle fasxiculi], wrapped round by the
    membraeous fibrillae [muscle fibers], constitute together the fleshy part
    of the muscle, which, soft,, broad and thick, differs in colour in diff
    animals, being reddish or pale or even whitish; in the leg of the rabbit
    you will find some muscles red and others pale. p.45-6

Louis-Antoine Ranvier, while working as an assistant to Claude Bernard in
1967, noticed that red muscles contracted slowly, developed fused tetanic
contractions at lower rates of stimulation, and were more resistant to
fatigue.  These were remarkable observations for the time and were not
equalled for many years.  46

Fast and Slow muscles

Derek Denny-Brown (b. NZ) in 1925 - working in Sherrington's large group at
Cambridge:
    gastrocnemius muscle (pale) in cat was faster than the (red) soleus, the
    small rectus muscles of eyeball were faster still.  The difference
    between gastrocnemius and soleus was reversed in the newborn kitten.

[Not until 1955 was this followed up] Histology work : stains for succinic
dehydrogenase, for myosin AtPase, and for muscle glycogen -  revealed
differently staining fibers distributed in an apparently random manner across
the muscle belly, giving a checkerboard appearance.  The myosin AtPase
reaction showed two main types of fiber (I and II)...

1965: Elwood Henneman, prof of physiology at Harvard:  isolated single motor
axons and correspnonding all-or-nothing antidromic response - the contractile
responses of individual motor units could be recorded.

Compared single motor units in the cat soleus and gastronemius muscles. p.49

* type I (slow) : The red soleus had long contraction times, and most of the
  tetanic tension was generated at relatively low stimulus frequencies.  The
  maximum twitch tensions varied more than 10-fold.

* type II (fast): In the pale gastrocnemius (fast) muscle, range of tensions
  were 100-fold, and greater range of contraction times also, with shorter
  ones predominating.  Required higher stimulus to develop maximum force.

Robert Burke : using glycogen depletion, counted individual fibers in a
single motor unit responding to single motoneuron stimulation.  showed that
fibers tend to be widely dispersed across the muscle belly.
[upto 3000 muscle fibers per alpha-motorneuron (MN);
motor neuron pool: group of alpha-MNs that innervates a muscle]

Showed that cat hindlimb muscles had three types of motor units:
 - large, readily fatiguable unit with a fast twitch (they termed this FF,
   Fast contracting, Fast fatigue; later termed: fast-glycotic, Type IIb)
 - a somewhat smaller unit, more fatigue resistant, with a slow twitch,
   (FR: fast contracting, fatigue Resistant, fast-twitch oxidative glycotic,
   Type IIa),
 - a considerably smaller unit, difficult to fatigue and with a slow twitch
   (S, slow contracting - slow-twitch-oxidative, Type I)

The glycotic / oxidative nomenclature due to Peters and Edgerton at UCLA, who
replicated the Burke results on rabbit and guinea pig.

small MNs: activate small, slow, aerobic muscles (type I, S)
large MNs: big fast anaerobic fibers (type II)
      IIa : fast, high force, easily fatigued
      IIb: moderate force, fatigue resistant

the type I (S) are first to be excited (small alpha-MNs) - always recruited
in exercise, then IIa (FR), finally IIb (FF).

Effects of exercise:
seen in the bushbaby, Galago senegalensis, by Edgerton etal, 1974.
moderate intensity (running) - mostly slow-twitch oxidative type I; exercise;
maximal (jumping) - used fast-twitch glycotic (type II).

Human experiments: possible after needle biopsy developed by Jonas Bergstrom
(1962, Sweden).  A very similar biopsy needle had been used a century earlier
by the remarkable French neurologist Duchenne (1806-1875)

Muscle fiber types in athletes:
Jansson and Kaijser, Sweden 1977: needle biopsy of quadriceps muscles;
orienteers have significantly higher %age of type I (slow contracting, type
S) fibers and smaller incidences of type II (fast contracting, fast fatigue,
type FF) fibers.  Similar differences shown on long-distance runners,
cyclists.

This diff was found to be correlated to exercise (Simoneau et al, Quebec,
1985).  Decreased proportion of type IIB fibers; increases in type I and type
IIA (fast contracting, fatigue resistant, type FR).

Simoneau fiber type alteration

Peter Schanz and Gurtej Dhoot, Stockholm: used recent advances in
immunocytochemistry to reveal that many of the fibers identified as one type
of another by histochemistry were actually in a transitional state,
containing both fast and slow isoforms of the contractile proteins.
Corroborated by Klitgaard in Denmark and Baumann in Switzerland.

Hill-Meyerhof theory (Nobel 1922): viscoelastic theory of muscle contraction.
  The essence of the theory was that the primary biochemical event in muscle
  contraction is the sudden release of lactic acid from a large precursor
  molecule, by then known to be glycogen.  The hydrogen ions, so liberated,
  would then neutralize negatie charges on the contractile proteins.  Freed
  from their negativity, the elastic proteins would fold and shorten. p.84

The theory was subsequently shown to be wrong.  Contradicted by:
 - Embden and Graffe 1921 : phosphate is also produced in contracting muscle

 - Wallace Fenn, 1923, visiting physiologist from Harvard, working in Hill's
   own laboratory: more heat is generated if the muscle performed work than
   if it contracted isometrically - difficult to reconcile w the idea of a fixed
   amount of lactic acid being released regardless of the nature of the
   contraction.  Hill was obliged to write: "Fenn has provided us with some
   very difficult problems".
   isometric contraction: without change of length, e.g. holding up a weight
    (the word "contraction" is used for several such non-changing muscle
     activations. Actual shortening of muscle is concentric contraction -
     force generated overcomes friction resistance

 - Eggleton (London) and Fiske/Subbarow (Harvard) 1927: phosphocreatine
   breakdown in contraction

 - death-blow to the Hill-Meyerhof theory, Lundsgaard 1930: muscle poisoned
   with iodoacetate was able to contract without producing any lactic acid at
   all. p.85