GR. 12 FITNESSGR. 12 FITNESS

ENERGY SYSTEMSENERGY SYSTEMSMr. Mackay

MUSCULAR SYSTEMMUSCULAR 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.

Carbohydrates

Fats

Proteins

ATP Muscular Work

Digesting Food

Thermoregulation

Breakdown of Energy currency Biochemical processes

ATP Breakdown

3

ATP H2O++ Energy++ P++ADP

ATP Resynthesis

ATPADP Energy++ P++

ANAEROBIC ALACTIC SYSTEM

4

ANAEROBIC ALACTIC SYSTEM

5

Primary energy source:

Duration of activity:

Sporting events:

Advantages:

Limiting factors:

Stored ATP, CP

7-12 s

Weight lifting, high jump, long jump, 100m run, 25m swim

Produce very large amount of energy in a short amount of time

Initial concentration of high energy phosphates (ATP, PC)

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

8

Primary energy source:

Duration of activity:

Sporting events:

Advantages:

Limiting factors:

Stored glycogen, blood glucose

12 s – 3 min

Lactic acid build up, H+ ions build up (decrease of pH)

800m run, 200m swim, downhill ski racing, 1500 speed skating

Ability to produce energy under conditions of inadequate oxygen

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

12

Primary energy source:

Duration of activity:

Sporting events:

Advantages:

Limiting factors:

Glycogen, glucose, fats, proteins

> 3 min

Lung function, max.blood flow, oxygen availability, excess. energy demands

Walking, jogging, swimming,

walking up stairs

Large output of energy over a long period of time, removal of lactic acid

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