Exercise Physiology

Aim

The unit provides learners with an understanding of how the body physiologically reacts to the onset and continuation of physical activity. It will also consider the mechanisms of fatigue and recovery.

To complete this unit students are expect to;

Be able to investigate the initial responses of the body to exercise

Exercise: aerobic; anaerobic

Cardiovascular responses: heart rate (anticipatory increase and activity response); stroke volume; cardiac output; blood pressure (calculating – resistance to flow multiplied by heart rate; readings)

Respiratory responses: increase in breathing rate; intercostal muscles; increase in tidal volume; Valsalva manoeuvre; pulmonary ventilation

Neuromuscular responses: nervous control of muscular contraction, eg neuromuscular junction, motor unit; muscle spindles

Energy system responses: adenosine triphosphate production; creatine phosphate and lactic acid system; anaerobic glycolysis

Be able to investigate how the body responds to steady-state exercise

Steady-state exercise: eg 20 minutes of continuous same-speed jogging, 20 minutes of an aerobics class, 20 minutes of continuous same-speed swimming

Cardiovascular responses: heart rate; stroke volume; cardiac output; blood flow (vasodilatation and vasoconstriction); blood pressure; thermoregulation; increased venous return; Starling’s law

Respiratory responses: tidal volume; breathing rate; effects of pH and temperature on the oxygen dissociation curve

Neuromuscular responses: increased pliability of muscles; increased transmission rate of nerve impulses

Energy system responses: adenosine triphosphate production; aerobic energy system; anaerobic glycolysis; mitochondria; Krebs cycle; electron transport chain

Know fatigue and how the body recovers from exercise

Fatigue: depletion of energy sources, eg creatine phosphate, muscle and liver glycogen; effects of waste products, eg blood lactate accumulation, carbon dioxide, increased acidity; neuromuscular fatigue, eg depletion of acetylcholine, reduced calcium-ion release

Recovery: excess post exercise oxygen consumption (EPOC); fast components, eg restoration of muscle phosphagen stores, removal of lactic acid; slow components, eg replenishment of myoglobin stores, replacement of glycogen

Know how the body adapts to long-term exercise

Long-term exercise: eg four 30-minute jogging sessions per week for eight weeks, a six-week resistance training programme

Cardiovascular adaptations: cardiac hypertrophy; increase in stroke volume; increase in cardiac output; decrease in resting heart rate; blood volume; capillarisation

Respiratory adaptations: increase in minute ventilation; efficiency of respiratory muscles; increase in resting lung volumes; increase in oxygen diffusion rate

Neuromuscular adaptations: hypertrophy; increase in tendon strength; increased myoglobin stores; increased numbers of mitochondria; increased storage of glycogen and triglycerides; neural pathways

Energy system adaptations: increased anaerobic and aerobic enzymes; increased use of fats as an energy source; higher tolerance to lactic acid

Skeletal adaptations: increased calcium stores; increased tendon strength; increased stretch of ligaments

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