Lucy Olivia Clarke
BTEC Level 3 Certificate In Sport
Unit 2 The Physiology of Fitness
The effects of exercise on the body
You are part of a research team, looking to investigate the short and long term effects of exercise
on the musculoskeletal, respiratory, cardiovascular and energy systems. Part of your work requires
you to conduct practical investigations into the physiological responses of the body response to ex-
ercise.
Task 1:
Know the body’s response to acute exercise
P1: Describe the musculoskeletal and energy system response to acute exercise
M1: Explain the response of the musculoskeletal and energy system response to acute exercise
The Musculoskeletal response:
The musculoskeletal response to exercise comes in the form of an increase in blood supply, an increased
range of movement, muscle fibre micro tears, and, also, an increase in the pliability of muscles (this linking
with the increased range of movement).
An increase in the supply of blood that our body receives comes from when we exercise. This in-
crease of bloody supply happens when our heart needs to beat at a faster rate, in order to deliver
oxygen to the working muscles at a much quicker rate than when we are resting. This is due to
there being a demand for oxygen, as our muscles are continually contracting. The blood vessels
dilate, allowing for more blood to get to the muscles; this takes the name of vasodilation.
Muscle fibre micro tears occur when there is a strain to the muscles, creating a tear to the fibres
that make these muscles up. These tears, after a recovery period, in which the muscle fibres fix
themselves, but in a lengthier form, will allow the muscles to become stronger than previously and,
depending on the type of training, if it is heavy weight training, for example, bigger, as well.
An increase of the pliability of our muscles can be defined as when they become looser and have a
wider range of flexibility, due to their temperature and warmth increasing. This is generally why a
warm up is done before we exercise, as to increase the warmth of our muscles. This increased
warmth of our muscles allows for a wider range of movement from this looseness and a flexibility
increase, reducing the risk of injury to out muscles and ligaments. Our body temperature increas-
ing also means that the synovial fluid in our joints becomes less viscous and is of a warmer tem-
perature, this making our movements more efficient and easy to do. As our muscles decrease in
tension, and increase in ‘looseness’, we are able to stretch our muscles further than we usually
can, while in normal, resting state. A tennis player’s warm up will be beneficial to them in the sense
that, as their muscles become looser and more flexible, especially in their arms, such as their tri-
ceps, or in their back such as their lattisimus dorsi, their range of movement will be increased, al-
lowing them to stretch further for a ball that has been retaliated back to them by their opponent.
This allows for an increased chance of hitting the ball, rather than them not warming up, and their
range of movement, therefore, not allowing for the stretching out of the limbs. Another sporting ex-
ample may include a football player, who require the use of their muscles, and muscular pliability
for movement around the pitch. Short sprint bursts within a footballer’s warm up may also help to
increase the performance levels of the footballer, due to giving them maximum muscular use po-
tential.
The energy system’s responses to acute exercise:
The energy systems in sport are known as phosphocreatine, lactic acid and aerobic systems. The
term energy continuum is the term that us used to describe the interaction of the 3 energy systems
that help to provide energy.
The phosphocreatine system, also known as the ATP-PC system, works by using phosphocreatine that is
used in exercises that require short, sharp bursts of energy, these such as proceeding from the starting
blocks in a race, such as a track race, or a dive off the blocks in a swimming event.
, Lucy Olivia Clarke
BTEC Level 3 Certificate In Sport
Unit 2 The Physiology of Fitness
The effects of exercise on the body
The lactic acid energy system harbours a short term effect that causes mucsular fatigue in our bodies. This
short term effect is the build up of lactic acid. We use this system when our Phosphocreatine store has run
out and when enough oxygen isn’t available for aerobic respiration. This system produces ATP at a fast rate
and, as well as it being at a fast rate, it can produce a lot of ATP. Anaerobic glycolysis (the breakdown of
glucose to produce ATP) is the source of the energy system’s ATP production. This is turned into lactic acid
when the ATP is broken down.
The last energy system is the aerobic energy system, this occurring in the mitochondria, organelles
responsible for the production of energy in the form of ATP. The short term effects of this system
include the reaction, shown by the formula, Glucose + oxygen--> 38 ATP + carbon dioxide + water
+ heat. A supply of oxygen that is constant is required for this process and as are stores of glyco-
gen. Glycogen in the name for glucose that is stored in the muscles. When this system has been
used for a long time period, the stores will need replacing though rest periods of around 12 to 48
hours.
P2: describe the cardiovascular and respiratory system to acute exercise.
The Cardiovascular systems’s responses to short term exercise:
The cardiovascular system undergoes a number of responses to exercise. These responses include an antici-
patory heart-rate response, an activity response, vasoconstriction, vasodilation and also an increase in our
blood pressure.
Anticipatory heart rate is where our heart rate is heightened more than our resting heart rate level, before
we are about to exercise. Our bodies are preparing to exercise, through ourselves thinking about participa-
tion in exercise and so the muscles are automatically supplied with more oxygen before we start to exer-
cise. When we also start exercising, the nerves in the brain detect our bodies undergoing cardiovascular
activity. The nerves then send signals to increase the heart rate. This process is due to the fact that the
nerves that supply our heart with blood flow increase the chemical response. These chemicals quicken the
pace of our heart rate through a response. The heat rate increasing means that the oxygen supply to mus-
cles is increased.
Vasodilation is the widening of the blood vessels, in order to increase the flow of blood to the working mus-
cles, and therefore, increase the oxygen supply that they receive. However, vasoconstriction can also occur,
a process that involves the blood vessels constricting (getting smaller), this meaning that less blood is
pushed through the blood vessels. Less oxygen is, as a result of this, delivered to the working muscles.
Vasoconstriction often occurs when we have eaten too soon before we exercise and blood is being sent to
the digestive system, in order to digest our food, rather than to our muscles to help contraction. This is an
explanation for our levels of performance being reduced.
Our blood pressure increasing is another response that our cardiovascular system undergoes in response to
exercise. When we exercise, a greater supply of oxygen is needed in the muscles. This supply of blood is
transported through the blood vessels. As the amount of blood that passes through the blood vessel in-
creases, the pressure on the wall of the blood vessel, ultimately increases. Systolic blood pressure can be
defines as the highest blood pressure that is possible when the heart is contracting progressively while ex-
ercise is being undertaken. On the other hand, the diastolic blood pressure can be defined as the blood
pressure that is the lowest blood pressure possible when your heart is at rest and not exercising.
The respiratory system’s response to short term exercise:
As we begin to exercise, our rate of breathing increases; there is a change in the total concentra-
tion of oxygen, along with carbon dioxide that is present in the blood, this being the main factor of
