Training in Cold Weather part 2
places high internal and external load demands on the human body. It must be
physically prepared to meet and exceed these artificially designed stresses. To
successfully adapt, conditions within the body must be favorable. Temperature
variations, however, can sometimes overpower the metabolic responses of the
States Air Force conducts one of the world’s premier Air Crew Survival Schools.
The training provided through this school specifically addresses cold weather
survival by stating the following in the instructor’s manual
is a serious stress source, even in mild degrees it lowers efficiency. Extreme
cold numbs the body and dulls the will to do anything except get warm”.
Cold numbs up the body by lowering the flow of blood to the extremities (we use
these in ALL of our exercises) and results in sleepiness”. (USAF, 38)
of Exercise Physiology state: “the normal heat transfer gradient is from
the body to the environment, and core temperature is generally maintained
without physiologic strain. In extreme cold however excessive heat loss can
occur, particularly when the person is resting.” (Katch, 502)
between sets is normal, especially when working in the 85-95% 1RM range. A
recent article by Jason Schniepp, et al.,in the Journal of Strength and
Conditioning Research, reported the results of test run on ten well-trained
cyclists’ and their response to the cold water immersion.
cyclists, who were exposed to cold water prior to a strength-cycling test,
clearly showed the adverse effects the cold temperature had on power output.
The cold affected blood flow, metabolism, and the balance of agonist-antagonist
muscular activity. “These factors will undoubtedly affect the rate of
energy production and muscular efficiency.” (Schniepp, p561)
G.M. Ferritti et al.’s work reported in “Effects of temperature on the maximal
instantaneous muscular power of humans”, Euro j. Appl. Physiol. 64:112-116.
1992 and cited by Schniepp “demonstrated a temperature-dependent
relationship on the rate of Adenosine Triphosphate hydrolysis, as a reduction
in ATP resynthesis occurs with a concomitant decrease in the rate of cross
bridge detachment. A relatively greater number of cross-bridge attachments have
been found in cooler muscles, resulting in an increase in power absorption
proportional to the external work required to lengthen the muscle.” If ATP
is slow in breaking down, power decreases cannot be far behind
Faulker, et al’s report entitled “Muscle temperature of mammals: Cooling
impairs most functional properties,” Am. J. Physiol. 28:259-265. 1990, (cited
also by Schniepp) suggests, in addition, that:
increase in power absorption by antagonist muscles after muscle cooling may
affect coordination, mainly manifesting at faster contraction velocities.”
“results from this study demonstrated a significant condition by trial
interaction as maximum power decreased significantly more after cold water
immersion than under normal conditions.”
cooler muscles there is an extended time of relaxation that reflects
prolongation of cross-bridge attachment and will result in a reduction of
cross-bridge cycling. A reduction in muscle temperature may also impair the
activation of motor units during a short time interval, possibly because of
lower nerve impulse frequency. As a result, coordinated movement may be
affected adversely. The body tries to remain at the optimum temperature through
a series of internal regulating mechanisms.”
thermo regulatory defense against cold is mediated by internal temperature NOT
by the body’s heat production per se,” according to Katch, et al. “The
greatest contribution of muscle to defend against cold occurs during physical
activity.” (Katch, 503)
Shivering is the body’s attempt to heat itself up through muscle action but it stops at core temperatures of 85-90 degrees. Normally a person exercising will not become this cold. If so then something is drastically wrong.
References Cited for Resistance Training in Cold Weather:
Arnheim, Daniel D. Modern Principles of Athletic Training.
Mirror/Mosby. 1989: 303-4.
Houston, Charles, S., M.D. Merck Manual of Medical
Information. Simon and Schuster. 1997:1345-7.
Katch, F.I, V.L. Katch, and W.D. McArdle. Exercise
Physiology. Lippincott. 1996 (4th ed.): 351, 502-3, 505-21.
Michele, Lyle, J. The Sports Medicine Bible. Harper Collins.
Schneipp, Jason, Terry S. Campbell, Kasey L. Lincoln Powell,
and Danny M. Pincivero. “The Effects of Cold-water Immersion on Power Output
and Heart rate on Elite Cyclists.” Journal of Strength and Conditioning
Research. 16 (Nov. 2002): 561
Search and Rescue Survival Training. Department of the Air
Force, USAF. 1985. (Currently in use at the Survival School)