App Phys week 4

bethdrysdale94's version from 2017-01-27 15:05

Section 1

Question Answer
What % of VO2 max are middle distance events run at?95-100%
According to Maughan and Gleeson 2004, what is the energy cost of 1 mile if run at around 120% VO2 max (VO2 max 70ml/kg/min)?334ml/kg oxygen cost - oxygen deficit was 71ml/kg/, VO2 allowed for 263ml/kg. >>> 80-85ml/kg/min required for 4 minute mile
What are the different times at 70% VO2 max that the different energy providing mechanisms give?PCr - 30sec, Glycolysis - around 3 mins. Aerobic CHO - 93 mins. Aerobic FFA - 10600 mins
Why is it difficult to accurately measure total energy turnover?both aerobic and anaerobic mechanisms supply energy.
What is the main limitation to the leg extensor test?not relevant for real life when all/more muscles in use
What is the FICK equation for oxygen uptake?CO x AVO2 difference
How do you measure for anaerobic metabolism?lactate release
What is a strength for the leg extension study?performed at VO2 max (65W) so is relevant for middle distance events
How long does it take lactate to begin accumulating in the leg extension test?accumulates in first 5 seconds
At beginning exercise in leg extension, what % is anaerobic energy providing?75% as aerobic metabolism is slower.
What are the total estimations of contribution of energy from aerobic and anaerobic pathways during the leg extensor?60:40 aerobic:anaerobic so BOTH contribute massively
What is the relationship between VO2 max and middle distance performance?strong positive correlation
What is Ingham et al 2008s model?allometric modelling of VO2 max and economy against performance speed in M&F 800&1500m runners
What is the interaction between VO2max and economy?vVO2 max - speed at which you reach VO2max
What is the correlation between vVO2 max and performance?strong positive correlation

Section 2

Question Answer
What represents your ability to sustain VO2 max?Tlim
What is Tlim related to?oxygen deficit and anaerobic capacity. higher anaerobic capacity = improved Tlim (time limitation)
Why are the limits to performance in anaerobic processes?rate at which energy must be supplied exceeds oxidative processes AND vVO2max is determined by the O2 deficit/anaerobic capacity
What role does lactate have in fatigue?no role
What molecules play a role in fatigue?H+, Na+ K+ (particularly potassium)
What does McKenna et al (2008) say about potassium and fatigue?as time of exercise increases, interstitial potassium increases. As potassium conc increases in interstitial fluids, peak tetanic force decreases
Gorostiaga et al (1991) - training and improved VO2 maxcontinuous training (30 mins at 50% Watt max) vs interval training (30mins at 30s work/30s rest at 100% Watt max) - VO2 increased more with interval training (36.3 to 42.2 ml/kg/min) however subjects probably didnt hit VO2max during training so is this specific? ALSO irrelevant to trained athletes who have VO2 max of like 70
Billat - maximising time spent at VO2 max continuous exercise at 50% difference between LT and VO2max vs intermittent exercise 30s 100% vVO2 30s 50% vVO2 >>>> intermittent allowed participant to stay at VO2 max for longer periods
What was strong about Billats study over Gorostiagas?Billat used elite athletes
Billat 1999 interval training frequencyonly 1 session/week for 4 weeks increased vVO2 max
What did burgomaster (2005) study show about muscle oxidative properties post conditioning?maximal activity and glycogen increased
What did burgomaster (2005 and 2006) show about time to fatigue and time to perform given amount of work post sprint interval training?greater endurance time to fatigue and less time to perform given amount of work compared to continuous work group
Leg extension - What happens to lactate and H+ release during submaximal exercise after training? Juel 2004overall increase but then decreases during exercise but lower levels overall after anaerobic training
Leg extension - What happens to lactate and H+ release during maximal exercise after training? (juel 2004)striking increase after training in comparison to before training
What happens when there is greater anaerobic capacity?greater anaerobic energy production, and content of lactate and H+ >>> extra H+ requires toleration, buffering or transportation from the muscle before it becomes limiting

Section 3

Question Answer
What are the physico-chemical buffers?bicarbonate, phosphate and proteins/peptides
Is there a clear consensus of effect of training buffer capacity?no, many contradicting studies
What is the function of MCT proteins?monocarboxylate transporter proteins - active transport of lactate and H+ out of cell
What MCT proteins are expressed in skeletal muscle?MCT1&4
What did Juel 2004 prove about MCT expression?increases with training

Section 4

Question Answer
What did carter et al (2005) find?prior heavy exercise results in improved performance in a time to exhaustion trial, enhanced performance was accompanied by reductions in both VO2 slow component and O2 deficit
What was the hypothesis of Inghams study looking at 800m running performance?high intensity warm up would speed VO2 kinetics and enhance 800m running performance in well trained athletes
What was the method in Inghams 800m study?11 athletes, 2x800m time trials on separate days. 2 different warm up procedures. 10 min self paced jog followed by either 6x 50m strides (control) OR 2x50m strides and a continuous high intensity 200m run at race pace - VO2 measured breath by breath during exercise
What were the results of Inghams study?high intensity warm up (HWU) increased: blood lactate, peak VO2 attained. decreased: time trial performance time. No change: response time for VO2
What was the conclusion of Inghams study?a sustained high intensity warm up enhances 800m time trial performances in trained athletes

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