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GR. 12 FITNESS ENERGY SYSTEMS Mr. Mackay MUSCULAR SYSTEM • Energy in the human body is derived from the breakdown of macronutrients like: carbohydrates, fats, and proteins. • The end result of this breakdown is the production of ATP molecules. • ATP provides energy for body functions. Breakdown of Energy currency Carbohydrates Fats Proteins Biochemical processes Muscular Work ATP Thermoregulation Digesting Food ATP Breakdown + H 2O ATP ADP + Energy + P ATP Resynthesis ADP + Energy + P ATP 3 ANAEROBIC ALACTIC SYSTEM 4 ANAEROBIC ALACTIC SYSTEM Primary energy source: Stored ATP, CP Duration of activity: 7-12 s Sporting events: Weight lifting, high jump, long jump, 100m run, 25m swim Advantages: Produce very large amount of energy in a short amount of time Limiting factors: Initial concentration of high energy phosphates (ATP, PC) 5 TRAINING • Interval training: – 20% increase in CP (creatine phosphate) stores. – No change in ATP stores. – Increase in ATP function (ATP -> ADP+P) – Increase in CP (creatine phosphate) and allows ATP resynthesis. • Sprint training: – Increase in CP stores up to 40%. – 100% increase in resting ATP stores. 6 ANAEROBIC LACTIC SYSTEM 7 ANAEROBIC LACTIC SYSTEM Primary energy source: Stored glycogen, blood glucose Duration of activity: 12 s – 3 min Sporting events: 800m run, 200m swim, downhill ski racing, 1500 speed skating Advantages: Ability to produce energy under conditions of inadequate oxygen Limiting factors: Lactic acid build up, H+ ions build up (decrease of pH) 8 Lactic Acid Threshold • The exercise intensity at which lactic acid begins to accumulate within the blood. • The point during exercise where the person begins to feel discomfort and burning sensations in their muscles. 9 TRAINING • Rate of lactic acid accumulation is decreased in the trained individual. • This rate can be decreased by: – Reducing the rate of lactate production. – Increasing the rate of lactate elimination 10 AEROBIC SYSTEM 11 AEROBIC SYSTEM Primary energy source: Glycogen, glucose, fats, proteins Duration of activity: > 3 min Sporting events: Walking, jogging, swimming, walking up stairs Advantages: Large output of energy over a long period of time, removal of lactic acid Limiting factors: Lung function, max.blood flow, oxygen availability, excess. energy demands 12 AEROBIC SYSTEM • The most important energy system in the human body. • Blood lactate levels remain relatively low. • Primary source of energy (70-95%) for exercise lasting longer than 3 minutes provided that: – Working muscles have sufficient mitochondria to meet energy requirements. – Sufficient oxygen is supplied to the mitochondria. – Enzymes or intermediate products do not limit the Kreb’s cycle. 13 TRAINING • Endurance training is the most effective method (long duration several times per week): • Increases vascularization within muscles. • Increases number and size of mitochondria within the muscle fibres. • Preferential use of fats over glycogen during exercise. • Endurance training increases the max aerobic power of a sedentary individual by 15-25% regardless of age. 14