Download Energy Continuum/The Recovery Process (b) Explain the term

Energy Continuum/The Recovery Process
(b) Explain the term OBLA and identify the factors that affect it during exercise.
4 marks for 4 of:
Sub max of 3 marks:
(Explanation)
1. OBLA – Onset of blood lactate accumulation
2. Occurs at 55–60% of VO2max untrained performers / 85-90% trained performers
3. Lactic acid reaches 4 millimoles per litre or 4 mmol/litre
Sub max of 3 marks:
(Factors)
4. Intensity of exercise
5. Respiratory exchange rate / RER
6. Muscle fibre type used in activity
7. Rate of blood removal / buffering capacity of blood
8. Fitness level of the performer / training
9. Soda loading / bicarbonate of soda (can delay OBLA)
(c) During a period of intense physical activity such as a 400m sprint or 100m swim there is a build
up of lactic acid.
(i) Explain why this build up of lactic acid occurs and what impact this build up has on
performance. [5]
Sub max 4 marks for
(why it occurs)
1 increase in recruitment of FG fibres
2 insufficient oxygen to meet demand re aerobic respiration
3 inadequate removal rate of lactate
4 more reliance on lactic acid system to produce energy for ATP resynthesis
5 more lactic acid is produced as by product of energy system
6 performer reaches their anaerobic threshold/lactate threshold/OBLA/blood lactate
concentration suddenly increases
Sub max 2 marks for
(impact on performance)
7 lactic acid lowers pH, inhibits aerobic enzymes (e.g. lipase)
8 lactic acid interferes with cross bridge formation/muscle contraction
9 lactic acid stimulates pain receptors
(ii) What can an athlete do to try and offset and delay the build up of lactic acid? [3]
1 athlete through training can increase their anaerobic threshold/lactate threshold
2 use of interval training/continuous training at or just above LT heart rate/fartlek
3 will increase tolerance to lactic acid
4 will increase removal rate of lactic acid
5 ensure sufficient carbohydrate intake in diet to match training needs
6 take sodium bicarbonate to act as a buffer for lactic acid
(c) Discuss reasons why the aerobic energy system is the predominant system used during
endurance events. [7]
(c) 7 marks from:
Alactic system
1 the alactic energy system not appropriate as it has short threshold / small amounts of PC
2 the alactic energy system not appropriate as it only produces small amounts of ATP
Lactic system
3 the lactic energy system / anaerobic glycolysis is not appropriate as it produces lactic acid
4 this eventually builds up/OBLA
5 causing fatigue
6 this system can only partially breakdown carbohydrate and cannot break down fat
7 there are only limited stores of carbohydrate
8 only produces limited amount of ATP / 2 ATP
Aerobic system
9 this system does not produce fatiguing by-products / carbon dioxide and water
10 this system can also breakdown fat
11 fat yields far more ATP per gram
12 the body has large stores of fat
13 this system can completely breakdown carbohydrate providing 36/38 ATP / high yield of ATP
14 can last a long time
1 (a) (i) During the recovery process the body returns to its pre-exercise state.
Describe the alactacid component of excess post exercise oxygen consumption (EPOC).[4]
1 (a) (i) 4 marks from:
1 the alactacid component occurs first
2 using some of the excess post exercise oxygen consumption
3 process restores the ATP / PC stores depleted during exercise
4 the energy for these reversible, endothermic reactions
5 is made available by the aerobic breakdown of fats and carbohydrate
6 the alactacid component takes between two and three minutes for full recovery
7 and uses up to 4 litres of oxygen / O2consumption remains high
8 it takes approximately 30 seconds to resynthesise 50% of PC stores
9 during this component the myoglobin oxygen stores are replenished