if you find this interesting, then please let me know
as I am looking at holding a half day seminar "Become a Better
Triathlete"
my theory being that if you learn how your body actually works, you
will become more efficient
for example, in A-level Physics 20 years ago, we learnt the rotational
dynamics of a sphere
I thought at the time, watching a football match, that I would be able
to 'bend' a ball well
now, I don't know anyone, not even a professional premiership player,
who can do it better
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The Triathlon and Physiology were chosen as the sport and academic
discipline respectively for the presentation. Triathlon was chosen
because it is a high endurance event and lends itself to studying the
physiological systems of the human body.

Triathlon, as an Olympic Sport, has a relatively recent history, as it
was first introduced as a competitive event in the year 2000 in Sydney,
Australia. The Olympic distance for Triathlon in the three disciplines
is 1.5km Swim, 40km Bike Ride and 10km Run.

It takes the average Triathlete about two hours to complete the Olympic
distance. In Athens 2004, the Women's Gold Medallist completed the
race in 2hrs 4m 33sec, whilst the Men's Gold Medallist, Hamish
Carter, from New Zealand, completed the race in 1hr 51m 7sec. He was
quoted as saying after the event, "I can't believe it man. I'm
so stoked!" Stoked being slang for excited or exhilarated.

As for the physiological systems reviewed in order to demonstrate their
use in the Triathlon, they are Energy Systems, the Cardiovascular
System and the Respiratory System.

The Energy systems to be looked at are ATP-PC, Anaerobic Glycolysis and
Oxidative Systems. ATP is a high-energy compound for storing and
conserving energy, ATP being short for Adenosine Triphosphate.

The immediacy, the intensity of the activity and whether or not oxygen
is present dictates which system the Triathlete's body will operate
to utilise energy available.

The ATP-PC system is most readily available for regenerating ATP. For
the first few seconds of physical exertion it will provide an almost
instantaneous supply of ATP. Phosphocreatine (PC) is stored in muscles
but is limited, so only 5-6 seconds of intensive activity may be
supported by this system. A Triathlete will utilise this system for
intermittent short, high intensity sprints in each of the three
disciplines of swim, bike and run. An alternative energy system will
be used for more prolonged forms of activity whilst phosphocreatine is
being regenerated by the body, which will lend itself to a new burst of
intensive exercise.

One alternative energy system is Anaerobic Glycolysis. In this system,
glucose is broken down into pyruvic acid, which is converted into
lactic acid when there is insufficient oxygen. On the two counts of
lack of oxygen in the muscle and too high a demand for ATP to be
produced by the aerobic system, the anaerobic Glycolysis system will
contribute to the production of ATP. This will cause a build up of
lactic acid, some of which will separate into lactate and hydrogen
ions, the hydrogen ions making the muscle more acidic and once there is
a build up of these ions, fatigue will set in. The triathlete will use
the anaerobic Glycolysis system over about 30 seconds for fast running,
swimming or cycling.

The other alternative energy system is the oxidative aerobic system,
which supplies the muscles with a continuous supply of ATP. Oxygen is
required for this system to function correctly. A triathlete will use
this system both at rest and during exercise. Fats and carbohydrates
are used in the aerobic system meaning that its fuel reserves are
larger and do not produce lactic acid. This system is the primary
source of ATP during low intensity activity and also contributes to the
supply of ATP for the other two systems so that the triathlete may
perform more intensive activities.

The effect of fatigue on the triathlete depends on energy provision.
The inability to provide energy through any of the three systems
described above will prevent a triathlete from competing in an
effective way. The production of energy depends on the delivery of
oxygen from the air via the blood stream to the muscles. This can be
investigated by looking at the cardiovascular system and the
respiratory system.

The muscles are the power plant of the body's energy, but a high
volume of oxygen is required to make this 'high performance engine'
perform efficiently, and is vital. The heart and lungs, known as the
cardiovascular and respiratory systems, provide this.

The oxygen that is in the air is taken into the lungs via pulmonary
respiration where it reaches a mass of alveoli bundles at the end of
bronchiole branches. Diffusion occurs across the respiratory membrane,
which is due to a partial pressure gradient. The oxygen is absorbed
into the red blood cells and plasma and is transported in the blood
stream to the muscles for internal respiration and energy creation. It
is the slow twitch muscle fibres, which are best suited for this to
happen, as this type of muscle gives high aerobic capacity and fatigue
resistance.

Carbon dioxide is the waste product of this process and passes back
through the system to be exhaled. During race conditions, this cycle
of inhale, exhale can occur every second.

A triathlete will have a maximum rate of oxygen consumption, which can
be measured and quantified as VO2max. As they become more efficient,
the amount of oxygen required for the same effort is reduced.

Triathletes not only train their arms legs and abdomen, but also their
breathing muscles, the external intercostals and the diaphragm. This
is known as IMT (Inspiratory Muscle Training) and is done by breathing
through a device that provides resistance against inhaling and
exhaling. It can give a small but significant increase in VO2max, thus
allowing a greater amount of oxygen during the race.

A triathlete's heart must be able to pump at around 80% to 90% of its
maximum rate (HRmax) over the two hours of the race. This means that
their cardiac output can be up to 35,000 ml/min, equivalent to filling
a 45lt fuel tank in 77 seconds.

It has been found that runners with less flexibility in their ankles
and hips run more economically as their muscles return more energy to
the next stride, as much as 30% more than a triathlete of the same
fitness. Many first time triathletes are surprised by the bizarre
sensations in their thighs a few hundred metres into their run after
the transition from cycling. This is due to the distribution and rush
of blood to the previously relaxed area of the upper body when on the
bike.

Looking at the key points on energy systems, we can see that
triathletes use ATP to generate energy to perform different forms of
muscular activity. They use their ATP-PC, Anaerobic Glycolysis and
Oxidative Systems to achieve high and low intensity activity during the
event to allow them to compete at a high level. Also, the key points
of the description of the Cardiovascular and Respiratory systems show
that a triathlete's heart and lungs must operate at close to their
maximum levels during the race in order to deliver sufficient oxygen to
the muscles. Specialist training can be done to increase muscle
capacity, but this must be coupled with an economical use of energy to
maximise the triathlete's potential.