Triathlon Study - Triathlon Week

DamianJB · 03-31-2006, 04:59 AM

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.