This is about the 400m sprint, and the energy systems that is uses, from Adenosine Tri Phosphate, to the Lactic Acid system

The event that I have decided to undertake from the Athletics unit this term and elaborate more on is knowledge and understanding of the 400-meter sprint.

This event is usually taken place on a full size athletics field, which consists of one whole lap in a fast sprint, which takes around a time of a minute.

In that minute the runner would experience all factors of the race, from intensity to recovery.

In the 400 meters, intensity relates to the chosen speed, which is usually expressed as a percentage of your maximum effort, and how hard you train.

Other aspects include Duration, which is closely linked to intensity. For example the higher the intensity of your exercise is, the shorter the duration will be.

Another major factor in the 400-meter race is endurance because the athlete must maintain a sprint for such a long distance compared to the 100 and 200-meter sprint.

These are only a few of the factors that contribute to the outcome, but a car cannot run on no fuel, just like our fuel for the 400m race is the energy systems.

There are 3 energy systems that we classify, from the amount of work we are creating for ourselves.

These consist of ATP, Lactic Acid, and Aerobic capacity

In the 400m though, we use two of the three energy systems.

The first, and the most valuable of all is Adenosine Tri phosphate, or simply, ATP, which is the immediate usable form of chemical energy for muscular activity. This is one of the most important of the "energy rich" compounds that is stored in all cells, particularly muscle cells. All forms of chemical energy available from the food we eat must eventually be transferred into ATP before the muscle cell can utilize them

Actively contracting muscles obtain Adenosine Tri phosphate (ATP) from glucose stored in the blood stream and the breakdown of glycogen stored in the muscles.

The body stores an energy rich compound in the muscles called phosphocreatine (PC). This breaks down and the free phosphate joins with Adenosine Di phosphate (ADP) to form ATP.

ATP usually lasts for about 10 seconds and then starts to kick into the next energy system, which is our last system for the 400m, the Lactic Acid system.

Lactic Acid is fatiguing metabolic of lactic acid system resulting from the incomplete breakdown of glucose. As the lactic acid is produced in our muscles it leaks out into our blood and is carried around our body. If this condition continues the function of the blood will become impaired and the muscles will fatigue quickly.

When running the 400 meters it is good to work the energy systems so when it comes to the final day, you body is capable of what needs to happen, and what is going to be involved. Training methods include

Speed Endurance Training.

There are many different types of sessions that athletes need to do to optimize

Speed Endurance. The catch is that to do too many sessions or sessions that

are too big or too intense will actually decrease speed endurance by damaging

energy systems. Repetitions of 10s or 20s or 40s or 50s all have very different

effects. Intervals with long rest run fast have very different effects to Intervals

with short rests.

The traditional way is to start slow and longer to build basic endurance and

then speed the sessions up as the year progresses.

· 10% faster than 400m pace - to improve leg speed and the ability to pick 'it up' in a race - specific endurance sessions would involve maximum distances of 200m in a single repetition with 5-10 min recoveries

· 400m race pace - to improve VO2 max and resistance to fatigue and train the body to operate at the required 400m pace- specific endurance sessions would involve maximum distances of 300m in a single repetition with 2-3 min recovery

· 10% slower than race pace - to improve lactic threshold and teach you to function for longer periods - helps when there is a number of heats before the final - specific endurance sessions would involve maximum distances of 500m in a single repetition with 30-90 sec recoveries.

The muscles are composed of a mixture of fibres - Fast Twitch & Slow Twitch. The fast twitch contract rapidly but fatigue easily whereas the slow twitch contract slowly but keep going longer.

The fast twitch muscle fibres are responsible for the high speed, high power movements over short periods of time. They use mainly carbohydrate for fuel and produce lactic acid, which as it builds up inhibits the muscle contracting.

The slow twitch muscle fibres produce less power but can continue for longer periods of time. They use a combination of carbohydrate & fat burned in the presence of oxygen and the main waste product is carbon dioxide that can easily be removed from the body.