I just did a PubMed search on the phrase "red muscle" and
got 600 hits from the peer-reviewed scientific literature. I
did a similar search on "white muscle" and got 1054 hits.
These are scientific terms, and not simply colloquial terms.
For example, here is a very relevant, very recent article:
1: Comp Biochem Physiol A Mol Integr Physiol. 2004 Jan;137(1):151-
60.
Red muscle recruitment during steady swimming correlates
with rostral-caudal patterns of power production in trout.
Coughlin DJ, Spiecker A, Schiavi JM.
Department of Biology, Widener University, One University
Place, Chester, PA 19013, USA.
[email hidden]
Rainbow trout (Oncorhynchus mykiss) and brook trout (or
charr, Salvelinus fontinalis) display different rostral-
caudal patterns of power production by the red or aerobic
muscle during steady swimming. The anterior muscle of
rainbow trout produces much less power for swimming than the
posterior, while in brook trout there is no variation in
power output. To determine if red muscle recruitment is
associated with anterior-posterior patterns of power
production, electromyography (EMG) was used to record red
muscle activity at three body positions across a range of
swimming speeds in fish of each species. The initial
recruitment of the anterior red muscle in swimming rainbow
trout was predicted to lag behind, i.e. occur at higher
speeds, that of the posterior due to the variation in power
production, but no variation in recruitment was expected for
brook trout. Burst of red muscle EMG activity occurring with
each tailbeat was analyzed for frequency (tailbeat
frequency), duty cycle (DC) (duration of burst relative to
the period of the tailbeat) and burst intensity (BI)
(magnitude of the measured EMG activity). Brook trout swam
with higher tailbeat frequencies and longer values of DC
than rainbow trout. Both species showed a pattern of
longitudinal variation in DC, with longer DC values in the
anterior red muscle. BI also differed significantly along
the length of rainbow trout but not brook trout. In the
former, BI of anterior muscle was significantly less than
the posterior at lower steady swimming speeds. The EMG data
suggest that power production and muscle recruitment are
related. In rainbow trout, where there is longitudinal
variation in muscle power output, there are also significant
rostral-caudal differences in red muscle recruitment.
Quoted message said:Quoted message said:
Fast twitch/slow twitch is useful terminology if you just
want to talk generally about power versus endurance.
But I've found that just about everyone can immediately
grasp the difference between turkey wings/breast and duck
wings/breast. This helps a lot in explaining the things I'm
trying to explain here. Namely that humans are more like
turkeys than like ducks. Ducks use their wings for
propulsion. So they are red. What does it mean to be red? It
means to have myoglobin (carries oxygen from blood to
mitochondria), to have mitochondria (which are red
themselves because of cytochromes and which metabolize both
lactate and fat, which white muscle fibers can't do), and
capillaries (which carry blood).
So this, among other things, shows why swimmers must spend
so much time (at least at some point in their lives) doing
such "insanely" long distance training. They have to convert
white fibers to red fibers, which is probably quite
difficult to do (as opposed to simply training the pre-
existing red fibers present in greater abundance in the
lower body).
I could say that turkeys have more fast twitch fibers and
ducks have more slow twitch fibers, but this doesn't elicit
the same "eureka" type of recognition in people to whom I'm
trying to explain it to as speaking in terms of red and
white fibers )as opposed to Type 1 and Type 2 fibers or slow
twitch and fast twitch fibers).
It's simply a way to make the explanations more immediately
intuitive.
