Physiology of middle distance events

Question 1

At what percentage of VO2 max are middle distance events generally completed at

Answer 1

95-100%

Question 2

explain the energy cost of running a 4 minute mile

Answer 2

would require a VO2 max of 80-85 ml/kg/min

elite athletes generally have a VO2 max of around 70

therefore aerobic processes will not be sufficient to meet the demands of the run

an oxygen deficit will be created (the area above the curve)

Question 3

roughly how long does it take for a person to reach their VO2 max and what is the implication of this

Answer 3

2-3 minutes

means that in the early part of the race there will be a large energy deficit if relying just on anaerobic processes

Question 4

what evidence is there that there is a high anaerobic contribution in the early stages of a race

Answer 4

depleation of creatine phosphate

production of lactic acid

Question 5

what are the overall energy contributions to the running of a middle distance race

Answer 5

0-30 seconds = 75% anaerobic (time delay of switch on of aerobic)

30-60 seconds = 50% each, ox. phos. now switched on

60-end = increasing contribution of aerobic due to increasing rate of ox. phos. being able to meet more of the demand

overall = 60% aerobic

Question 6

what are the 4 determinants of performance in middle distance events

Answer 6

VO2 max
running econonmy
vVO2 max
T lim

Question 7

define vVO2 max

which two other factors combine to determine vVO2 max

Answer 7

the running velocity at which a runner achieves their VO2max

it is a product of VO2 max and running economy

Question 8

define Tlim

explain what is infered by a greater Tlim

Answer 8

the maximal amount of time which a runner can sustain their vVO2 max for

a bigger anaerobic capacity because the longer you run at VO2 max the more of an oxygen deficit you create

Question 9

what is considered to be the limit to performance in middle distance events

Answer 9

Anaerobic capacity (these determine the vVO2 max)

specifically H ions and Na/K pumps

Question 10

ouline the methods and findings of the trial into the best way to improve VO2 max for middle distance events

Answer 10

continuous vs HIIT training
30 mins constant work at 50% VO2 max
30 seconds off 30 on at 100% VO2 max

statistically significant increase in VO2 max with HIIT, not seen with continuous training

Question 11

offer some critique of the work on training interventions to improve VO2 max

Answer 11

VO2 max values published were relativly low so may not see the same benefits in elite athletes

short intervals and regular breaks probs meant VO2 max wasn’t reached so may have got more benefit if altered to reach VO2 max sooner

Question 12

outline the methods and findings of the trial into the best way to improve time spent running at VO2 max

Answer 12

continuous group vs interval group

continuous ran at a speed half way between LT and VO2max until fatigue occured

interval group ran for 30 secs at 100% vVO2 max and 30 seconds at 50% vVO2 max

interval group spent longer at VO2 max

1 session per week saw marginal increases in VO2 max and significant increases in vVO2 max

findings have been validated by other studies
similar studies also demonstrated a resulting improvement in 300m times

Question 13

outline the methods and findings of the study into training to improve aerobic capacity

Answer 13

8 week trial

single leg knee extension at 150% thigh VO2 max
15 x 1 min intervals with 3 minute rest

post training thigh muscle was able to achieve a higher VO2
muscles also had increase citrate synthase and glycogen

similar trials have shown greater time to fatigue and less time to perform a given amount of work vs controls

Question 14

outline the methods and findings of the study into improving anaerobic capacity

Answer 14

same 8 week knee extension intervention

increased the amount of workload achieved and the time to fatigue

at submax intensities there was a reduction in lactate production (increased lactate threshold)

at maximal intensities there was an increase in lactate production (able to produce more lactate so increase in anaerobic function)

Question 15

what are the potential problems with increasing an atheletes anaerobic capacity

Answer 15

will increase the production of fatigue causing metabolites e.g H

no use if the body is unable to tollerate these

Question 16

what has been the overall findings from trials investigating the potential for training to improve buffering capacity

Answer 16

mixed findings

but these variables are hard to measure so this may be why

Question 17

what is the function of the MCT protein and how does it work

Answer 17

to remove lactate from cells

lactate and dissociated H bind, ATP utalised to remove them to the outer side of the cell

Question 18

outline the methods and findings of the trial into training to improve lactate and H transport

Answer 18

same 8 week knee extensor intervention

increased amounts of MCT1 and MCT4
representing and increased ability to transport fatigue causing metabolites

Question 19

outline the evidence to support doing a warm up at higher intensities than normal to enhance middle distance performance

Answer 19

normal warm up vs warm up at 90% CP

90% saw 1 min increase in time trial to exhaustion
also saw a decreased VO2 slow component and a decreased O2 deficit

similar protocol used by Jess Ennis in London 2012 and ran a PB for 800m

Question 20

give the key points from the reading from the paper on the high intensity warm up

Answer 20

overall speeding up of the VO2 kinetics

this would attenuate the reduction in Pcr and decrease accumilation of fatigue causing metabolites e.g h

during trials total VO2 used was greater so greater contribution of total energy utalisation from aerobic sources
more aerobic + same full use of anaerobic = greater total energy yield