Physiological adaptations

Question 1

RHR

Answer 1

Resting heart rate – The minimum number of beats per min required of the heart to maintain body function (basal metabolic oxygen needs) at rest.
After sufficient training, an athlete’s resting heart rate decreases as their cardiovascular system is more efficient and there is an increase in SV. The more aerobically trained an individual, the quicker their heart rate returns to resting levels post-exercise.

Question 2

SV and CO

Answer 2

Stroke volume – The amount of blood pumped out of the left ventricle of the heart per contraction (beat).
- An increase in SV results from training and allows the same amount of blood to be transported around the body with fewer heart contractions.
Improved performance will come with thickening of ventricular wall (ventricular hypertrophy) allows for a more powerful contraction and increases elasticity and this means it can expand further and fill up with more blood (increase in venous return).

Thus a higher SV increases the oxygen available to the working muscles and results in improved performance.

Cardiac output – The amount of blood pumped out of the left ventricle of the heart per minute. (SV x HR)
- Training causes increased maximal cardiac output as a direct result of an increased SV.

Question 3

Oxygen uptake and lung capacity

Answer 3

Oxygen uptake (VO2) – The amount of oxygen the body uses in a minute
- A high VO2 max indicates superior oxygen delivery system and contributes to better endurance performance.
As a result of training with increased volume and intensity, VO2 max can be increased.

Lung capacity – Amount of air the lungs can hold and the amount of air that can move in/out during a breath.
As a result of training the size of lungs do not change but efficiency improves:
- Strength and endurance of lung tissue and surrounding muscle increase = greater volume of air can be inhaled and exhaled + faster ventilation
- Increases number of capillaries in lungs = more oxygen to be absorbed with each breath
THE GREATER THE VOLUME OF AIR THAT CAN BE INHALED  GREATER AMOUNT OF O2 CAN BE ABSORBED INTO BLOOD  MORE O2 AVAILABLE TO WORKING MUSCLES.

Question 4

haemoglobin levels

Answer 4

Haemoglobin – Molecule in RBCs that binds to oxygen and transports it around the body.
- Aerobic training stimulates the body to produce more haemoglobin in order to increase the oxygen-carrying capacity of the blood = improving aerobic performance.

This increased ability to utilise the aerobic energy system as a result of increased haemoglobin delays the need to rely on the anaerobic energy system and helps avoid fatigue caused by lactic acid build up.
- Thus increased haemoglobin = increased workload at which the athlete reaches their anaerobic threshold. This allows the athlete to maintain higher intensities for longer periods of time, as they remain in their aerobic training zone.

Question 5

muscle hypertrophy

Answer 5

Muscle hypertrophy – Muscle growth and increase in size of muscle as a result of strength/resistance training.
- As a result of training muscle size increases, however overload principle must be applied to stimulate/place stress on muscles.

Question 6

Slow twitch muscle fibre

Answer 6

SLOW TWITCH FIBRES
Contract slowly and release energy gradually as required by the body during steady-state activity. They are efficient in using oxygen to generate energy (ATP), making them resistant to fatigue but unable to produce the power of fast-twitch fibres.
- Recruited when engaging in endurance type activities (marathon running)

• Hypertrophy: Endurance activities recruit slow-twitch fibres which can result in growth.
• Myoglobin content: Endurance training increases myoglobin content drastically (is the oxygen carrying capacity for your cells)
• Mitochondrial function: Results an increase in the number of mitochondria as well as their size and efficiency in producing ATP which improves performance as the body has more muscle-contracting energy that can be produced.