pediatric housecalls Robert R. Jarrett M.D. M.B.A. FAAP

Children’s Athletic Warmups

January 4, 2012

Ask even the most novice little league sports participant and he will tell you that you are supposed to “warm up” before a game or practice.

When asked why that is necessary, studies have shown that even many college-age athletes are unaware of the actual physical benefits.
Teen athlete showing off

Athletic Warm-ups For Children

Warm-ups do more than just prevent “stiff muscles,” they actually decrease the risk of injuries and increase performance.

The majority of these benefits are probably related more to an increase in muscle temperature than any other of the effects like acceleration of the respiratory and cardiovascular systems or increase in certain hormone levels.

Let’s list some of the benefits of increased muscle temperature, which is what “warming up” does.

Hemoglobin, the compound which carries the oxygen in the blood, gives up its oxygen more rapidly and completely at slightly elevated temperatures.  This improves the energy efficiency of the muscles.

In addition, various cellular enzymes for energy production are enhanced and activated at slightly increased temperatures.  This makes for more efficient use of the energy stores during a physical activity.

Another benefit is that impulses travel down the nerve fibers more rapidly at increased temperatures.  And in addition, the end receptors seem to be more sensitive.

The athlete can then perform more quickly and with greater coordination.

The blood vessels in the muscles dilate (get larger) with warm-up, thereby allowing more blood flow to the area.  This increases the delivery of energy materials and removal of waste products.

Other benefits relate to how flexible and pliable structures are at increased temperature.  The viscosity (thickness) of the fluid within each cell is slightly lowered at higher temperatures.  This of course makes it easier for the muscles to move.

Muscle elasticity (stretchiness) is increased with better blood flow, so warm muscles have less risk for injury.

Studies on exercise machines have shown that contraction of warm muscles is more rapid and forceful than cold muscles.

Warm-ups have definite benefits and one study has even shown a substantial risk factor if you don’t warm up.

Researchers studied normal, healthy men without previous symptoms of heart and lung problems.

They put them on a treadmill and gave them sudden, strenuous exercise for ten to fifteen minutes without warm-up and found that 70% had abnormal ECG tracings, indicating a lack of oxygen in the heart.

It showed this had nothing to do with the level of physical fitness or age and was either eliminated or improved if preliminary warm-up preceded the exercise.

Types of Warm-ups

There are generally three different types of warm-ups.  The passive, the general, and the specific.

A passive warm-up would be through external means like using a heating pad or shower.  This is not as effective and difficult for most athletes.

The general warm-up would be like doing a broad range of calisthenics prior to the athletic event.  This increases internal muscle temperature and is therefore much more preferred.

The specific warm-up would be exercising those muscles which will be used in the event; also a much more preferred type.

For example, a sprinter would concentrate on running slowly at first and progressively increasing the speed.

As the warm-up progresses, the sprinter would begin taking short, low intensity starts and progressing to an activity of approximately 70% of maximum.

Because the specific warm-up not only increases muscle temperature but provides a short of rehearsal, this is the type of warm-up that is most preferred.

The duration and intensity of the warm-up should be individualized to be competitive.  Warm-ups should not progress to fatigue.  A fifteen minute warm-up used by most novice and amateurs would be inadequate for a more professional caliber athlete who should probably require 30 minutes.

An increase in rectal temperature of approximately one to two degrees centigrade seems to be sufficient for all of the above mentioned benefits.  This roughly correlates with the onset of sweating in an adult, which for an adult may be a good indicator.

A child, however, remember does not sweat as readily and would be better off relying on core temperatures when trying to decide how much time is needed for an adequate warm-up.

Temperature takes approximately 45 minutes to return to normal at rest, so the warm-up should not be too far in advance of the anticipated exercise.