pe a level paper 1 - energy systems

Breakdown of ATP

Breakdown of ATP

ATP - A-P-P-P (1-2 secs) , ATPase → ADP - A-P-P + P

ATP-PC system/alactic system

PC →(creatinekinase) P (phosphate) + C (creatine) + 1 ATP yield (2-10 secs)

takes place in muscle sarcoplasm

lactic acid system/glycolytic system

Glycogen → (GPP) glucose → (PFK) pyruvic acid + 2 ATP yield (10 secs - 3 mins) → (LDH) lactic acid

takes place in muscle sarcoplasm

Aerobic glycolysis

glycogen (in presence of o2) → (GPP) glucose → (PFK) →pyruvic acid + 2 ATP yield → (Coenzyme A) acetyl CoA

takes place in the muscle sarcoplasm

Kreb’s cycle

Acetyl CoA + oxaloacetic acid → citric acid → Co2 + oxaloacetic acid + hydrogen+ + 2 ATP yield

takes place in the matrix of the mitochondria

Electron Transport Chain (ETC)

H+ (carried by NADH → FADH) → cristae folds of mitochondria → H2O + 34 ATP Yield

About ATP-PC system

exothermic, anaerobic, ATP yield = 1:1, high intensity (e.g. long jump), ATP is only usable form of energy to allow us to do work, duration of system = 2 - 10 secs

5 strengths of ATP-PC system

1. no fatiguing byproducts

2. PC stored in muscles so readily available to be broken down

3. not reliant on o2 being present - fast reaction chain

4. allows performer to do explosive work

5. anaerobic reaction

2 weaknesses of ATP-PC system

1. low yield compared to other energy systems

2. PC gets used up very quickly and stores are limited

About lactic acid system

exothermic, anaerobic, ATP yield = 1:2, high intensity (e.g. 200m running), duration of system = 10 secs - 3 mins

OBLA

onset blood lactate accumulation - lactic acid being produced quicker than it is being removed

4 strengths of lactic acid system

1. anaerobic

2. fast reaction chain (no o2)

3. glycogen is readily available in large quantity in muscles and liver

4. provides energy to work at high intensity for 10s - 3mins

2 weaknesses of lactic acid system

1. fatiguing byproduct (lactic acid) - decreases performance intensity

2. low yield compared to aerobic system

About aerobic system

aerobic, ATP yield = 1:38, low to moderate intensity, duration of system = 3 mins - 2 hrs

3 strengths of aerobic system

1. provies energy for longer duration

2. no fatiguing byproducts

3. high ATP yield

weakness of aerobic system

reliant on o2 - decrease in intensity of exercise

Energy continuum

the relative contribution of each energy system to overall energy production

4 factors that affect interplay of energy systems

intensity of exercise, duration of exercise, recovery periods, fitness levels

EPOC

excess post-exercise oxygen consumption (o2 debt)

4 stages of recovery

1. pre-exercise state

2. alactacid stage

3. lactacid stage

4. oxygen deficit

Fast alactacid component of recovery

10% of EPOC, 1-4 litres of oxygen required to return body to pre-exercise state, replenishes blood + muscles with O2, takes 3 mins, resynthesises ATP + PC stores, first minute of EPOC - o2 resaturates the blood stream, associating with haemoglobin, within 3 mins - restores oxymyoglobin link in muscles

Slow lactacid component of recovery

EPOC required 5-8 litres of o2 to return body to pre-exercise state, 1hr - up to 24 hrs, provides energy to maintain ventilation + circulation + body temp, removes lactic acid + replenishes glycogen

3 key processes of fast alactacid component

1. saturates haemoglobin with oxygen to form oxyhaemoglobin and transport it to muscles + restore oxyhaemoglobin in muscle cells

2. resynthesises ATP

3. restores PC using energy from aerobic system to put P+C together

5 key processes of slow lactacid component

1. ventilation (maintains BR, delivers o2, removes CO2)

2. circulation (carboaminohaemoglobin in plasma and blood carry Co2 back to lungs)

3. body temp (if body temp remains high, BR stays high to take in more o2)

4. lactate removal - LA converts into PA →CO2, H2O, ATP (50-75%), glycogen to store in muscles/liver (20%), glucose (5%)

5. glycogen (from lactate removal, taken in through eating complex carbs)

Warm up - implications for recovery

increases HR, respiratory rate, MR - accelerates use of aerobic system, decreases use of anaerobic system + reduce o2 deficit, limits amount of o2 needed to pay back during EPOC

Active recovery - implications for recovery

maintains respiratory rate + HR to flush muscles + capillaries w o2, requires 40-60% VO2 max = decreases time for lactate removal + decreases time for slow lactacid component

cooling aids - implications for recovery

used post event to lower muscle and blood temp to resting levels, speeds up lactic acid removal, decreases muscle damage, decreases DOMS, reduces MR and demand on slow lactacid component

Intensity of training - implications for recovery

monitor intensity of training using HR specifically to energy systems, high intensity = boosts efficiency of fast alactacid component, low intensity = delays OBLA using aerobic energy production

work:relief ratios - implications for recovery

explosive intensity - work:sleep ratio = 1:3+, high intensity = 1:2, endurance = 1:1/2:1

strategies and tactics - implications for recovery

set plays and low intensity = delays OBLA and fatigue, delay play and low intensity = no lactic acid and ATP+PC acceleration

nutrition - implications for recovery

maximise PC stores (creatine/phosphagen/protein = increased ATP-PC efficiency), maximise glucose + glycogen (complex carbs), LA eased by bicarbonate nitrate = lower o2 costs and enhances o2 w/ blood