Ass 1

1. Unit 33: Functional
Exercise Physiology
Samantha Lawson SL151872

2. ATP-PCr Energy System
During sprints and sports which involves quick movements like a badminton player playing a serve requires a rapid and immediate
energy supply, this is called the ATP-PCr system which consist of adenosine triphosphate (ATP) and phosphocreatine (PC) when these
stored phosphates are broken down providing they are stocked up this is when energy is released for maximal intensity lasting up to 10-
15seconds before it fatigues. ATP is stored in many cells throughout the body when ATP is broken down to release energy one single
phosphate leaves, leaving ADP adenosine diphosphate. Phosphocreatine (PC) is then broken down by the enzyme creatine kinase into
creatine and Pi to re-join forming ATP allowing the process to start over breaking down to release energy for fuel activity. Within 2
minutes rest in-between maximum intensity will allow ATP to replenish.
Figure I: Processes of regeneration of ATP
Figure I shows the ATP-PCr cycle. Energy is eaten as carbohydrates which
then gets turned into glucose and is stored within the muscles, it is then
converted to ATP which allows the muscles to use it for energy this is
when one phosphate it released, releasing energy making the muscles
move make it ADP. A phosphocreatine is then added back on to ADP
converting it back into ATP for the cycle to then begin again enable us to
get immediate energy when sprinting for the finish line in a 100m sprint.

3. The Glycolytic System
In this stage oxygen is not used to synthesise ATP. Like ATP-PC system it is quick at producing energy, how ever they do not last very
long resulting in early stages of fatigue. When the body is in need of short energy burst after using up the ATP-Pc system it moves onto
the glycolytic system using glycogen as energy. In swimming (50m freestyle) this system is the most used system out of the three
meaning the swimmer will be in constant need of glycogen resulting in them needing to eat plenty of complex carbohydrates which will
fuel their swim before they begin. Glycolysis can generate energy only half as quickly as ATP-PCR producing 16 kcal (calories) per
minute.
This system is associated with lactate system, this system doesn’t happen as quickly as the ATP-PCr system as it is more complex. There
are four major steps to this system.
1 - Stored glycogen is converted to glucose which is broken down by a series of enzymes.
2 - 2 ATP are used to fuel glycolysis and 4 are created so the body gains 2 ATP to enable the muscles to contract and work.
3 - The breakdown of glucose to synthesise ATP produces1 'pyruvate' and hydrogen ions. The muscle becomes increasingly acidic as more
hydrogen ions are created.
4 - Because this system is ‘anaerobic’ there isn’t enough oxygen to break down pyruvate and synthesise anymore ATP. (PT, 2017)
This results in pyruvate binding together with some of the hydrogen ions and converting them into lactate which acts as a temporary buffering
system to reduce acidosis, the building up of acid in muscle cells and no more ATP is synthesised.

4. The Oxidative System
The oxidative system has the lowest rate of power output out of all the energy systems only producing 10 kcal (calories) per minute.
After 90 seconds of a continuous activity when the ATP-PCr and Glycolytic system have been used up this system kicks in, the oxidative
system is the primary source of ATP at rest and during low intensity exercise. Fats and carbohydrates are the primary source for this
energy system. This energy system happens in the presents of oxygen. Training long and slow distances can help improve and build an
aerobic base and help strengthen the oxidative system by increasing VO2 Max. Internal training can help us recover by increasing the
bodys ability to decrease blood lactate levels as well as making us more proficient at replenishing oxygen debt.
ATP can be produced three ways in this system. The krebs cycle is a sequence of chemical reactions that continues to oxidize the glucose
that was initiated during glycolysis. The hydrogen which is produced in the Krebs cycle and during glycolysis causes the muscles to
become too acidic if not tended to, to stop this from happening hydrogen combines with the enzymes NAD and FAD which is then sent to
the electron transport chain. More chemical reactions happen here and hydrogen combines with oxygen. Water is produced and acidity
is prevented. The krebs cycle and the electron transport chain metabolize triglycerides which is stored fat and carbohydrates to produce
ATP. The break down of the stored fats (triglycerides) known as lipolysis are glycerol and free fatty acids although before fatty acids can
enter the krebs cycle they enter a process called beta oxidative where a number of chemical reactions downgrades them to acA and
hydrogen, which then enters the krebs cycle and fat is metabolized just like the carbohydrates. (Cann, 2016)
Figure I: The Krebs Cycle Figure II: Electron Transports Chain Figure III: Beta Oxidative

5. Figure I: Working at high intensity showing which energy system is used.
(Mac, 2017)
Depending on the sport/exercise and the intensity depends what
energy system is used. Majority of sports uses the ATP-PCr and
glycolytic system in the beginning stages then they go on to use the
oxidative energy system. Walking at a steady pace low intensity would
use the oxidative system where as doing a 100m sprint the body
would use the ATP-PCr system.
The result of muscle contraction produces ADP, when CP is added is
produced ATP again enabling there to be more energy which can be
used for short bursts. When active and contracting muscles ATP is
obtained from glucose which is stored in the blood stream and the
breakdown of glycogen stored in the muscles. Exercise for longer
periods of time requires the complete oxidation of carbohydrates or
free fatty acids in the mitochondria. The carbohydrate store will last
around 90 minutes and the free fatty store will last several days.
All three energy systems contribute at the start of exercise but the
contribution depends on the individual, the effort applied or on the
rate energy is used. (Davis et al, 2000) shows how the energy systems
contribute to the manufacture of ATP over time when exercising at
100% effort. The thresholds (T) indicate the point at which the
energy system is exhausted, training will improve the thresholds
times. (Mac, 2017)
Over View of Energy Systems

6. Task 2
100 Metre Race
During a 100 metre race the ATP Store is what is used for a quick bursts of energy, this will be in high demand at the beginning of the race. The ATP-PC system
is the energy system which supplies the energy in the first 10 seconds of the race when the ATP-PC supplies have depleted the lactic acid system takes over
which lasts up to around 2 minutes, after two minutes of sprinting the athlete will be entering the aerobic energy system this will require oxygen through
breathing harder which will help to replenish the ATP-PC system to enable the athlete to have enough energy to sprint to the finish line at the end of the race.
This diagram illustrates the energy systems used in exercise over the duration of exercise. (Weebly, 2017). There is
always a dominant source of energy production although all of the energy systems contribute towards one another.
Figure 1: Energy systems used in exercise
1500 Metre Race
When running a 1500 metre race the first 100 metres is quick so that optimal position is gained, during this stage the ATP-PC system is used to power through
the opponents. From 100 metres to 1100 metres the pace slows, but maintains a steady pace this would be using the aerobic system and during this time the
ATP-PC system will be replenished enabling the athlete to be able to pick up the pace in the final 400 metres before the final 100 using the ATP-PC system for
the first 10 seconds then the lactic acid system just before the finishing line.

7. Energy Production
There are different fuel which is used by different energy systems.
ATP-PC which produces quick bursts of energy PC
(phosphocreatine) is stored in the sarcomere and PC combines
creatine and phosphate by using high energy bonds.
Anaerobic glycolysis is fuelled by glucose which is stored in the
muscles and live in the form of glycogen, glucose can be taken from
muscle glycogen or transported from the blood via the liver. There
are enzymes in the bodies cells which convert glucose into lactic
acid which produces ATP, double the amount of ATP is produced
getting glucose into the cells.
When using the aerobic energy system the main starting fuel is fat,
carbohydrates and proteins, these are delivered to the
mitochondria (Figure I) and broken down to yield ATP. The waste
product of hydrogen ion (H*) is bonded to oxygen to form water
and the other waste product is CO2 (carbon dioxide) which is what
is breathed out. (Glass, et al., 2017).
Figure I: Mitochondria Structural Feature
(Davidson, 2015)

8. Task 3
At 5km the intensity is low, lactic acid starts at 2.4mmol and
dips to 2.2mmol before rising again. Lactic acid removal is
greater than lactic acid accumulation. Not much of our energy
is produced by the lactic acid system most of our energy is
from the aerobic source.
On set of blood lactate accumulation (OBLA) generally occurs
when the concentration of blood lactate reaches about
4mmol/L (6,7). (Davies, 2016)
At a speed of 7.5km/h blood lactate is 4mmol that OBLA which
means energy is coming from the lactic acid energy system.
Vo2 value and Vo2 are the same value with dividing by each
other the results will be 1.0 therefore this means all the energy
is coming from the carbohydrate stores, such as un-saturated
sugars. Speeds above 7.5km/h lactic acid accumulates and the
RER (respiratory exchange ratio) value is above 1.0.
Figure I: OBLA
OBLA training is running at the fastest speed possible while
still recruiting energy from the aerobic rather than the
anaerobic system. If a client is training for OBLA, they will be
running at the fastest speed they can at which their lactic acid
production is just lower than their body’s rate of lactic acid
removal. Once they go beyond this level, the high lactic acid
levels will make it impossible for their muscles to continue
exercising. (Luke, 2013)

9. References
Cann, K., (2016). Understanding the Oxidative Energy System and How to Properly Feed It. [Online]
Available at: https://breakingmuscle.com/fuel/understanding-the-oxidative-energy-system-and-how-to-properly-feed-it
Davidson, M., (2015). Mitochondria. [Online]
Available at: https://micro.magnet.fsu.edu/cells/mitochondria/mitochondria.html
Davies, P., (2016). The Lactate Threshold. [Online]
Available at: http://www.sport-fitness-advisor.com/lactate-threshold.html
DAVIS, B. et al. (2000). The Interrelationship of the energy system and their threshold points . In: Physical Education and the Study of Sport. s.l.:s.n., p. 139.
Energy, 2016. Energy Metabolism. [Online]
Available at: http://pages.uoregon.edu/mdillon1/Energy%20Metabolism/Energy%20Metabolism.html
Glass, S., Hatzel, B. & Albrecht, R., (2017). Three ways the body produces energy. [Online]
Available at: http://www.dummies.com/health/exercise/3-ways-the-body-produces-energy-to-fuel-metabolism/
Katch, V., Katch, F. & Mcardle, W., (1994). In: Essentials of exercise physiology.
Luke, H., (2013). OBLA Training. [Online]
Available at: http://www.cmsfitnesscourses.co.uk/blog/113/obla-training
Mac, B., (2017). Energy Pathways. [Online]
Available at: https://www.brianmac.co.uk/energy.htm
PT, (2017). PT Direct. [Online]
Available at: http://www.ptdirect.com/training-design/anatomy-and-physiology/the-anaerobic-glycolytic-system-fast-glycolysis
Weebly, (2017). Factors affecting performance. [Online]
Available at: http://dalebeattie.weebly.com/energy-systems.html