Every human body has an uncountable number of individual muscle fibers. A certain proportion of the fibers are fast twitch while the remaining fibers are slow twitch. The proportion is determined genetically before birth.

Fast twitch fibers predispose a person to quick, explosive movements such as those necessary to chase ball across a tennis court or to successfully cover a streaking wide receiver in football. Fast twitch fibers may be thought of as those fibers that characterize sprint type movements.

Slow twitch fibers, on the other hand, are best thought of as muscle fibers which allow for excellent performance in endurance type activities. The most obvious example are long distance runners, however, slow twitch fibers regulate many other non-explosive type of athletic movements.

A person with a high proportion of slow twitch fibers as compared to fast twitch fibers may have excellent hand eye coordination, tremendous muscle definition, among a full range of other important athletic characteristics; however, their chances of excelling at wide receiver on a football team would be seriously impaired.

Currently very few athletes in America have any idea as to their proportion of fast twitch to slow twitch fibers. Needless to say, children are totally clueless. Their adaptability to a certain sport or sport position is less scientific or reality based than say, astrology or palm reading. Contrast that to the old Iron Curtain nations where children's muscle fibers types were known well before their hair color would stabilize.

The most accurate way to assess muscle fiber type proportions is with a simple needle biopsy. Of course, this procedure must be carried out in your local sportsmedicine physician's office or at one of the large University based sportsmedicine research facilities. Fortunately, it is fairly painless and relatively inexpensive; once you find the appropriate professional with access to the appropriate laboratory to do the "typing."

As always, though, there are alternatives. Not as accurate as a sophisticated laboratory technique but practically speaking, for Sport Election, just as useful. And even better, one procedure can be done in 30 seconds using the side of a house.

The first couple of steps in any athletic movement are a direct function of the proportion of fast versus slow twitch fibers in the legs. The simplest test for this is the Vertical Jump.

Directions:

1. Find a high wall.
2. Have your child face the wall with the toes touching the wall and the heels firmly planted on the floor. 3. Have your child fully extend both arms overhead and have their fingers touching the highest point they can reach on the wall.
3. . Mark that spot.
4. Have your child move one foot back from the wall.
5. Have your child jump with legs together, without a running start and touch the wall at the highest point possible.
6. Mark the spot they reached. Let them take a couple of practice jumps and then let them jump for a score.
7. Measure the height between the first and the second mark. You can use a yardstick. (If they jumped beyond the yardstick, don't bother measuring. Just grab a couple of plane tickets and get here as quickly as possible. I'll want to act as agent/coach for all their future athletic endeavors.)
8. Use the table below to find the number that corresponds to their jump performance. Use the body weight column that is closest to them. TABLE 1
9. Having found the number on the table above, look at the scoring key below and translate the result into points. Place the point score in the appropriate Vertical Jump scoring box located on your child's overall scoring sheet.

TABLE 2

Males			Females			Points

360			220			15.0
342-359			207-219			13.5
324-341			193-206			12.0
307-323			180-192			10.5
289-306			167-179			9.0
271-288			153-166			7.5
253-270			140-152			6.0
236-252			127-139			4.5
218-235			113-126			3.0
200-217			100-112			1.5