John Noel
SPH4U
Mr. Pardo
Olympic Challenge
September 2008
Introduction
Nature of the Problem:
A friend of the author wishes to participate in athletics in the next Olympic
games. Said friend has asked for help in deciding which athletic event to participate,
based on his anthropometrical measurements. The author will both research
anthropometrics and measure his friend and suggest which sport his friend is best suited
for.
Purpose Statement:
The purpose of this investigation is to discover the effect of upper limb
proportional ratios on athletic performance.
Hypothesis:
Performance in athletics events at the Olympics depends, in part, on certain
anthropometrical characteristics.
Rationale:
The upper limb ratios of athletes, in part, influence their success in certain athletic
events. The brachial index measures the proportional ratio between the forearm and the
upper arm. The general population has an average index percentage of 74.8 % ± 4.2 std
for men and 75.% ± 4.6 std (Olds, Norton, 1996). Male athletes in most sports stand
above this average, but below 82%. Runners, both track sprinters and marathon runners,
have an average of approximately 77%, but the range stretches from 72-80%.
Interestingly, the values for most female athletes are below the general average (Olds,
Norton, 1996). A high brachial index, in general, is useful for sports in which longer
propulsive drive of the forearm is needed. A high brachial index allows for longer stroke
length because the forearm is a longer lever, therefore increasing the velocity of the hand
at the end of the stroke (Olds, Norton, 1996). This is extremely useful for throwing sports
as javelin and discus where the athlete wants to have the thrown object at the highest
possible velocity as it leaves the hand. On the other hand, a lower than average brachial
index provides greater strength and stability (Olds, Norton, 1996) . An athlete with a low
index tends to have “short force arms” which are an advantage in athletics such as shot
put in which a tremendously forceful push is needed. This occurs because the muscle
mass is more concentrated in the arm (Westat, 1988).
A high upper limb length to stature ratio means that the athlete has long arms in
respect to the rest of his/her body. The normal population has an average ratio of 44.1% ±
1.4 for men and 43.4% ± 1.4 for women. Runners, both marathon and sprint, tend to have
a value that is below average. Having a high upper limb: stature ratio gives the athlete a
longer lever to accelerate an object in throwing events. The arm itself acts as a third class
lever in which the shoulder is the fulcrum, and the item being thrown the load (Ryan,
2002). A third class lever does not increase strength with length, but it does increase
speed with length (Poarch, 2002). This relationship is significant for javelin or discus
throwing. Long arms maximize the release velocity of the object, giving the largest
distance for amount of muscle mass. The relationship can also be used by athletes such as
shot putters who require a single and large push. A short third class lever increases its
maximum strength (Poarch, 2002). A shot putter needs to achieve the maximum strength
form his/her arms so as to achieve the most forceful push.
It can then be accepted that both a high brachial index and a high upper limb to
stature ratio are beneficiary for athletes in throwing events such as javelin, hammer and
discus. A low value in either of the two ratios aids in power throwing events such as shot
put. In the running events, arms are not used heavily, but shorter arms help in running
events because they produce less drag, the force that resists an object moving through a
fluid (Elert, 2008).
Table 1: Upper Limb length to stature (male) (Olds, Norton, 1996)
Table 2: Upper Limb length to stature (female) (Olds, Norton, 1996)
Table 3: Brachial Index (male) (Olds, Norton, 1996)
Table 4: Brachial Index (female) (Olds, Norton, 1996)
Methods
Materials:
Measuring tape
Procedure:
Two different anthropometrical ratios were researched in this study: the brachial
index (forearm: upper arm), and an upper limb length: stature ratio.
A) Brachial Index
1. The length of the upper arm was measured using a measuring tape. The upper arm
was measured along the posterior of the arm from the tip of the acromian process
to the tip of the olecranon process. During the measurement, the subject stood
erect, with feet together, and arm bent ninety degrees at the elbow with palm
facing up. The right arm was measured. (figure 1)
2. The length of the forearm was calculated, also with a measuring tape. The
measurement was taken along the anterior of the forearm with palm facing up.
The length was taken from the tip of the olecranon process to the tip of the stylion
process. Again, the right arm was measured. (figure 2)
3. The brachial index was calculated by dividing the length of the forearm by the
length of the upper arm and multiplying the quotient by 100% to get a percentage
ratio.
B) Upper Limb: Stature Ratio
1. The length of the hand was taken from the tip of lower tip of the radial to the tip
of the third digit on the right hand. The measurement was taken with palm facing
up. (figure 3)
2. The length of the hand was added to the upper arm and forearm lengths taken in
part A to calculate the total upper limb length.
3. The total upper limb length value was then divided by the subject’s stature and
multiplied by 100% to calculate a percent ratio. The stature value was obtained
from Lee, 2008.
(Olds, Norton, 1996) (Westat, 1988)
Figure 1: Measurement of Upper Arm (Westat, 1988)
Figure 2: Measurement of Forearm (Olds, Norton, 1996)
Figure Three: Measurement of the Hand (Olds, Norton, 1996)
Figure 4: Skeletal Structure of the Arm
References
Ryan, V (2002). Levers. Retrieved October 2, 2008, Web site:
http://www.technologystudent.com/forcmom/lever1.htm
Poarch, M (2002). Bones as Levers. Retrieved October 2, 2008, Web site:
http://www.science-class.net/Anatomy/Support/Bones%20as%20levers.pdf
Elert, G (1998-2008). Aerodynamic Drag. Retrieved October 1, 2008, from Hyper
Textbook Web site: http://hypertextbook.com/physics/matter/drag/
Retrieved from "http://science.nmdhs.net/wiki/index.php?title=Brandon"
Olds, T & Noton, K (1996). Anthropetrica. Austrailia: USNW Press.
Westat, Inc (1988). Body measurements (anthropometry). National Health and Nutrition
Examination Survey III
Kent, M.(2007). Sports Science and Medicine. The Oxford Dictionary of Sports Science
and Medicine. Oxford Press. London.
Lee, N(2008). Stature. Olympic Challenge.