The Dunk, or, How to increase your Jumping Ability.

by Aleck H Alexopoulos

The following information was taken from an article from
The Chicago Tribune (May 5 1991).

The article was written by a journalist (Eric Zorn) who wanted to
reclaim his ability to dunk at the age of 33. He's 6'4"
and could dunk up to the age of 30. He stopped playing
for a year, put on 20-30lbs and could no longer dunk.

He goes around asking all these "jumping specialists"
from all over the country what makes a guy dunk.

So he goes and tests his vertical jump: 22 inches.
Compare that to Michael Jordans 48inches…… So he cuts
out snacks from his diet and "that second bowl of cereal".

n order to dunk (at a regulation 10ft rim) you need to have
a reach of 10'6" for a two handed dunk and 10'8" for a one handed.
You get a longer reach with one hand but its more difficult to control
the ball.

So he started out with daily one mile runs that ended in 60 jumps.

He sought advice from Dave Smith a director of strength and weight training
and an ex Univ of Illinois BBall player.
He put him on a program that started with 5minutes of warmup calisthenics
followed by 5-10minutes of jumping practice folloed by 15minutes of
leg exercies: leg presses, leg extensions, and hamsting curls, 3sets of 15reps.

From research he initially conducted he found that the experts disagreed on
the importance of individual muscle groups on jumping ability. Others claimed
the key was the calves, others said it was the quads, the glutes, the
abs (!) etc.
Many things have been claimed to be useful: dancing, jumping with weighted
vests, rope skipping, etc.
One guy claimed that chinups where helpful and another guy claimed that using
your big toe to the max put an extra inch on your leap instantly.

One thing that the experts seem to agree on is that jumping depends on
explosive strength. Explosive strength depends in part on the number of
fast twitch fibers you have which is - as far as we know - determined
genetically. So to increase your explosive strength you increase the size
of the fast twitch fibers by doing "fast-twitch exercises".
Slow-twitch fibers wont do anything. In fact they may hurt!

A VERY interesting result was found at Ball State University on marathon
runners and long-distance swimmers. Most of them had PATHETIC vertical
leaps - 12inches on average. Went these athletes stopped their
long-distance training their vertical leaps INCREASED to the normal
low 20inch range. Somehow the excessive growth of slow-twitch
fibers "strangles" the fast twitch fibers and limits their action.

Sports trainor Randy Smith (consultant to the Dallas Cowboys) and author
of the manual "Jumping Higher" puts it bluntly: "Cease and desist jogging.
Athletes should never, ever jog until they are old and used up like I am".

Another fact - related to the previous - is the importance of speed.
If it takes you too long to expolde upwards after you crouch down you
lose too much elastic energy. Jumping specialists refer to
"contact time" the amount of time you step down before you jump.
The smaller the better, and the higher you jump.
Chicago Bulls strength trainer Al Vermeil measured the reporters
contact time at 0.29 seconds. Michael Jordon's? 0.16 seconds….
The key here is that you have to train your nervous system to
fire quickly and thus reduce your contact time.
To increase both the size of your fast-twitch fibers AND to train your
nervous system Vermeil suggests a program based on explosive exercises
like the squat, the clean and jerk, and the snatch.

A category of explosive exercises are the so called plyometric exercises.
In these exercises the muscles undergo sudden stress and then quickly
rebound. For example running up stairs two at a time, or stepping of a box,
landing, then leaping as high as possible, etc
Such exercises teach the neuromuscular system to contract quickly and
efficiently, thereby helping develop the skill components to jumping.
These exercises look at leaping ability as a skill (says Doug
Semenick conditioning coordinator of the Univ. of Luisville BBall team).
Trainer Randy Smith of Speed City Inc. Portland Oregon sells a device
that is basically a platform with some elastic cords. You tie these
cords around you, you jump up as high as you can, the crods pull you
down, you jump up again etc. A human jackhammer.
The Soviets where really into that in the past as Michael Yessis discribes
in his "Secrets of Soviet Sports Fitness and Training" where he describes
some guys jumping of 10ft platforms (ouch!). The problem with these exercises
is that you can get injured real easy. Its mostly for people
allready in pretty good shape.


The conclusions I draw from this article is that one should first
reduce his excess body weight by dieting and aerobics. Then one should
do just enough aerobics to keep his weight down. From that point on the
emphasis should be on explosive exercises.

Pretty much what we knew allready.
The negative effect of extreme long-distance training on your
explosive strength is very interesting though….


source: newsgroup, 6 Feb 1993

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