physiology

Physiology.

Defining fitness: - ‘the ability to carry out everyday activities without undue fatigue.’ or ‘the ability to meet the demands of your environment or lifestyle.’.

Defining health: - ‘a state of physical, social and mental well being where we are free from disease.’.

Components of fitness.

· Cardio respiratory endurance (aerobic capacity) (stamina).

· Muscular endurance.

· Strength.

· Speed.

· Coordination.

· Power.

· Flexibility.

· Reaction time.

· Agility.

· Balance.

· Body composition.

Stamina or cardio respiratory endurance (aerobic capacity): - ‘the ability of the cardiovascular and respiratory systems to take in and transport oxygen to the working muscles where it can be utilized and aerobic performance maintained.’.

E.g. A triathlete requires high amounts of cardio respiratory endurance but a weightlifter doesn’t.

Factors influencing cardio respiratory endurance include: -

· Efficiency of gaseous exchange at both lungs and muscle cells.

· Effectiveness of oxygen transport from the lungs to the muscle cells.

· Ability of the muscle cells to utilize oxygen that they receive.

Performers with high cardio respiratory endurance may possess the following: -

· Greater capillarisation of the alveoli and muscles.

· Greater concentration of red blood cells, and therefore haemoglobin, in the blood, which helps transport the oxygen to the working muscles.

· A greater proportion of slow oxidative muscle fibers.

· Greater concentration of myoglobin within the muscle cell, which helps to store the oxygen and transport it to the mitochondria.

· A greater number and size of mitochondria, which can utilize the oxygen to provide energy.

Tests for stamina/cardio respiratory endurance include: -

· The multi stage fitness test.

· The Harvard step test.

· The PWC170 cycle ergometer test.

· The cooper 12 minute run test.

Most test of cardio respiratory endurance seek to discover a persons VO₂ max or maximal oxygen uptake. (The maximal volume of oxygen that a person can take in, transport and utilize per minute.).

Strength: - ‘The ability of the body to apply a force against a resistance’. There are different types of strength including; -

1. Maximum strength: - The maximum force that can be developed in a muscle or group of muscles during a single maximal contraction.

Maximum strength is dependent on factors including; -

· Cross sectional area of muscle – greater the cross sectional are of pure muscle mass, the stronger the performer.

· Amount of fast twitch muscle fibre – fast twitch glycolytic muscle fibres are designed more for maximum strength.

E.g. a performer requiring maximum strength is a weightlifter.

2. Elastic strength: - the ability to overcome a resistance rapidly and prepare the muscle quickly for a sequential contraction of equal force.

E.g. sports performers requiring high levels of elastic strength include sprinters, triple jumpers and gymnasts.

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