----- Original Message -----
From: Tobias Sundberg <[log in to unmask]>
To: List - Physio; Inlägg <[log in to unmask]>
Sent: Thursday, December 16, 1999 9:56 PM
Subject: warm-up effects
> Dear listers,
>
> Is there anyone out there aware of any scientific studies on the effects
of various warm up procedures on physical performance (spec. related to
short term bouts of exercises like jumping, weight lifting, sprint running
etc.). I have used on-line internet search engines and PubMed/Medline with
little result. Funny thing is that allmost every sports medicine textbook
claim the enhancing effects of a warm-up, but I have yet to see specific
references to back that up! Any thoughts on resources/references/other?
Thanks you for your time.
>
> Sincerely,
>
> Tobias
>
>
> --------------------------------------------
> Tobias Sundberg, PT
> [log in to unmask]
> --------------------------------------------
Hi Tobias,
Just a few thoughts on warming up. As you say there's not much research to
exactly quantify the effects of warming up on performance but here's a few
points you may already know:
A rise in muscle temperature increases the conduction velocity across the
sarcolemma which increases the frequency of stimulation and hence the
production of muscle force (Phillips, C .A, and Petrofsky, J. S.:Mechanics
of Skeletal and Cardiac Muscle. Springfield, IL, Charles C Thomas, 1983).
Increased temperature also causes greater enzymatic activity which further
increases muscular efficiency (Frankel .V .H and Mordin. 1989. Basic
Biomechanics of the Musculoskeletal System. USA. Lippincott Williams and
Wilkins.) Collagens elasticity also improves as temperature rises, leading
to greater extensibility and greater possible prestretch and hence possible
force production of a muscle. This positive effect on the collagen and
elastin units to deform will also reduce the chance of injury due to violent
overstretching. Another couple of references that may be worth looking at
are:1) Shellock, F. and Prentice, W. E. 1985. Warm up and stretching for
improved physical performance and prevention of sport related injury. Sports
Med 2:267-78. 2) Safran, M. R., et al: The role of warm up in muscular
injury prevention. Am. J. Sports Med., 16:123,1988.
A quick summary of basic physiological considerations, increased muscle core
temp and blood flow can lead to:
Increased speed of contraction and relaxation of muscles.
Lower friction resistance within muscles and joints hence greater economy of
movement.
Increased/more efficient oxygen utilization as hemoglobin releases oxygen
more readily at higher temps.
Improved muscle metabolism and nerve transmission.
Increased blood flow through active tissues which increases delivery of
oxygen and nutrients and the removal of wastes.
A number of studies have evaluated the cardivascular response to strenuous
exercise both with and without a warm up. One study clearly demonstrated an
improved ECG and blood pressure response in the warm up group compared to
the immediate strenuous exercise group (Bernard, R.J., et al.: Ischemic
response to sudden strenuous exercise in healthy men. Circulation, 48:936,
1973).
There are also psychological considerations where pre practice of skills can
enhance co-ordination and accuracy (although I don't have any research to
hand I'm sure Schmidt or Singer have done plenty of research on this). It
may also be worth considering that an athlete who has warmed up gradually
may feel more ready to commit to maximal exertion than an athlete who
launches straight into maximal exertion without a warm up (From a personal
perspective, when I'm training I'm fairly sure that I couldn't perform at my
maximum level instantaneously without a warm up, although this may come from
my pre-programming that tells me that I need to warm up gradually, there
again I think most athletes will also have this pre-programming).
When I was rooting around in the library the other day I came across a
recent article on the scientific research behind warming up, unfortunately I
can't remember which journal, but if you have access to them it may be worth
having a glance at the contents of The Canadian Journal of Applied
Physiology, The Journal of Strength and Conditioning and the NSCA Journal of
applied Biomechanics (I'm not sure if this is the correct title but it is
definately the journal of the NSCA).
In view of the above, is it worth not doing an appropriate and specific warm
up??? Regardless of the fact that performance increases have not been
quantified and isolated due to the warm up alone.
Hope this is some use,
Steve Aspinall.
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