In the 5000m race the runner must use all 3 energy systems , which are ATP, aerobic and lactic acid systems to succeed as the race has different areas needed for their use, all 3 energy systems contribute regardless of the intensity or duration of the exercise. When the athlete comes to the starting line he/she most probably will want to make a dashing start to the race to tactically get a good starting position, so must get off the line, in the first 40-50m, as hard as he or she can. By getting off the line as fast as the athlete can, they will both set themselves up with a good strong fast early rhythm, but also by getting near to the front of the pack they will be able to choose their position in the early portions of the race. But to achieve take off and the short sprint they must use the creatine phosphate system which uses ATP molecules as energy for any muscle contraction to occur, obviously when exercising at a high level like sprinting more ATP are needed to supply the energy, but because stores only last for up to 4 seconds the body needs a system that can re-synthesise adenosine die phosphate in to Adenosine tri phosphate very quickly when an individual starts to exercise. Carbohydrates, fats and proteins are digested to provide a source of energy. Carbohydrates are usually in the short term and fats are mainly used in the long term, protein is used as a stand by source of ATP. To get carbohydrates we can eat foods such as potatoes, rice, bread and fruit, and when they are digested they release glucose which is then stored in the body as glycogen, to supply energy to the phosphates, this is known as anaerobic glycolysis, and also used when exercise is at high intensity. The athlete does need to be weary of how long they use this system at the start of the race because could run out of fuel to supply the ATP which can only run anaerobically for up to 3 min which would lead to an unwanted substance early on in the race called lactic acid which would…