Transcript Document

ACUTE RESPONSES TO
PHYSICAL ACTIVITY
YEAR 11 PE
ACUTE RESPONSES TO PHYSICAL
ACTIVIT Y
 ACUTE RESPONSES- Immediate, short-term
responses to exercise that last only for the duration
of the training or exercise session and recovery
period.
ACUTE RESPONSES OF THE MUSCULAR
SYSTEM TO PHYSICAL ACTIVIT Y
INCREASED MOTOR UNIT AND MUSCLE FIBRE RECRUITMENT AND
MUSCLE CONTRACTIONS
 When exercise begins, motor unit recruitment must increase
so that more muscle fibres can be activated to contract.
 The greater the force required, the greater the number of
motor units recruited and the greater the number of muscle
fibres activated for contraction.
INCREASED BLOOD FLOW TO THE MUSCLES
Due to increase demand for oxygen during exercise, this leads
to:
 Vasodilation of capillaries
 Redistribution of blood from organs to skeletal muscles.
ACUTE RESPONSES OF THE MUSCULAR
SYSTEM TO PHYSICAL ACTIVIT Y
INCREASED MUSCLE TEMPERATURE
Increase in muscle temperature during
exercise is due to:
 Increased blood flow to working muscles
 Heat generated as a by -product of ATP
production
INCREASED OXYGEN SUPPLY AND
UTILISATION
 Increase in oxygen supply due to
increased demand of ATP during exercise.
 DEPLETION OF MUSCLE ENERGY STORES
 Muscular sources of fuel for energy
production (ATP, PC, glycogen and
triglycerides) begin to deplete during
exercise.
ACUTE RESPONSES OF THE
CARDIOVASCULAR SYSTEM TO PHYSICAL
ACTIVIT Y
INCREASED HEART RATE
 Heart rate increases with increasing exercise intensity to
assist with greater demand for oxygen for muscle contraction
and removal of wastes.
INCREASED STROKE VOLUME
 Stroke volume increases due to increased demand for oxygen
for muscle contraction during exercise, allowing more blood to
be pumped from the heart with each beat.
INCREASED CARDIAC OUTPUT
 Cardiac output increases during exercise due to increase in
heart rate and stroke volume.
ACUTE RESPONSES OF THE
CARDIOVASCULAR SYSTEM TO PHYSICAL
ACTIVIT Y
INCREASED SYSTOLIC BLOOD PRESSURE
 During exercise, blood is being pumped more forcefully into
arteries, due to increase demand for oxygen supply to active
muscles.
INCREASED BLOOD FLOW AND BLOOD VESSEL DIAMETER
 Speed and volumed of blood flow to active muscles increasing
with exercise, causing blood vessels to increase in diameter
(vasodilation).
BLOOD FLOW REDISTRUBUTION
 Blood is redistributed to active muscles from other areas of the
body where not required during exercise, to increase supply of
oxygen to working muscles.
 Blood flow can also be redistributed to skin for the removal of
heat (produced as a by -product to energy production).
ACUTE RESPONSES OF THE
CARDIOVASCULAR SYSTEM TO PHYSICAL
ACTIVIT Y
INCREASED BODY TEMPERATURE
 Increase in body temperature occurs due to an increase in
metabolism by active muscles. As muscles work harder to contract,
more heat is produced as a by -product of exercise .
INCREASED ARTERIOVENOUS DIFFERENCE ( a-VO² dif f)
 Comparison of amount of oxygen in veins compared to that in the
ar teries.
 With increasing exercise intensity, the amount of oxygen in veins
(blood returning from body) is lower than at rest, causing a greater
dif ference in oxygen concentration in ar teries and veins. No change
in oxygen concentration of ar teries during exercise.
INCREASED CORONARY CIRCULATION
 Blood vessels that supply cardiac muscles has an increase in blood
flow during exercise.
 Increase in coronar y circulation is needed to supply for oxygenated
blood for increasing workload as hear t rate also increases
ACUTE RESPONSES OF THE RESPIRATORY
SYSTEM TO PHYSICAL ACTIVIT Y
INCREASED RRSPIRATORY
(BREATHING) RATE
 Respiratory rate increases
during exercise due to an
increase demand for oxygen
and removal of carbon dioxide.
INCREASED TIDAL VOLUME
 Tidal volume increases with
increasing exercise intensity to
supply oxygen to working
muscles.
INCREASED VENTILATION
 Due to increases in respiratory
rate and tidal volume during
exercise, ventilation also
increases.
ACUTE RESPONSES OF THE RESPIRATORY
SYSTEM TO PHYSICAL ACTIVIT Y
NO CHANGE TO VITAL CAPACIT Y
 Lung volume remains unchanged, as it can not be increased as a
short term effect to exercise.
 Can be reduced due to asthma, bronchitis, emphysema etc.
INCREASED OXYGEN UPTAKE
 Oxygen uptake increases with increasing exercise intensity.
 Oxygen uptake will not increase further once maximum level of
oxygen uptake is reached (VO² Max)
 INCREASED EFFORTS FROM RIBCAGE MUSCLES AND DIAPHRAGM
 Diaphragm and intercostal muscles will work harder to enable
increased expansion and contraction of thoracic cavity.
 The increased movement of the cavity can accommodate an
increased air volume, required to supply active muscles with
oxygen