Exercise Intensity Domains Flashcards
Define exercise intensity
How we categorise an ind. physiological response to external work.
Define normalising
Attempt to ensure the ind. experience an equivalent physiological demand.
When is it important to ‘normalise’ exercise intensity?
In any scientific study when measuring the physiological or perceptual impact of an intervention. i.e substance utilisation
When designing effective exercises training prog. i.e to stimulate adaptation
Why account for exercise intensity?
To ensure we’ve got participants exposed to the same physiological demand.
What can obscure real differences in scientific experiments?
Intra + inter ind differences or variability in results.
Lactate threshold occurrence varies widely between ind.
Between what %
30-85% VO2 max
What are the 4 exercise intensity domains accepted by Burnley & Jones, 2007?
Moderate
Heavy
Severe
Extreme
– ONLY easily classifiable during constant work-rate exercise.
Intermittent exercise inv. dynamic transitions between the exercise intensity domains.
Burnley & Jones, 2007
Moderate exercise intensity
All intensities below the LT
Burnley & Jones, 2007
Heavy exercise intensity
Above LT + below max steady state
Burnley & Jones, 2007
Severe exercise intensity
Above max steady state
Achieving VO2 max
Burnley & Jones, 2007
Extreme exercise intensity
Exhaustion before VO2 max
What is the VO2 slow component?
A slow component
Evident after 2-3 mins
Where is the VO2 slow component found?
ONLY above the LT
i.e never during moderate intensity exercise
What happens to the V02 slow component during heavy intensity exercise?
Eventually levels off (steady state)
What happens to the V02 slow component during severe intensity exercise?
Projects to VO2 max
NO steady state
What happens to the V02 slow component during extreme intensity exercise?
Exercise in this domain isn’t typically long enough for the slow component to be determined.
What is the most likely explanation of the VO2 slow component?
That its related to additional fibres being recruited throughout exercise to replace those that have become fatigued.
These fibres are therefore contributing to forced prod + O2 requirement = resulting in continued drift upwards in the O2 uptake response.
What was the 1st study to provide direct evidence that type 2 fibre recruitment is associated with the VO2 slow component?
Krustup et al. 2004
Definition for cycling economy or gain
Amount of O2 its costing us relative to the work load
How is cycling economy or gain calculated?
Change in VO2 / change in work load
What is the lowest available power output on a standard ergometer?
20 Watts (even if the ergometer says 0)
How is change in work load calculated?
End power - Baseline power
Moderate exercise in its simplest description
All work rates below LT
Blood lactate is NOT elevated
VO2 ⬆️ at ~10ml/min/W
For how long can moderate exercise be continued for?
~4hrs
Reasons for fatigue in moderate exercise
Muscle glycogen depletion
Muscle damage
⬆️ core temp.
HR in moderate exercise
Steady state attained w/in 3 mins
Blood lactate in moderate exercise
Not elevated above baseline/resting values
What happens w/ VO2 in heavy exercise intensity
After 2-3 mins VO2 continues to ⬆️ via the slow component
What happens as the heavy exercise is conducted close to the lactate threshold?
The smaller the VO2 slow component
What is crucial to remember about heavy exercise?
That even if exercise is completed to exhaustion, VO2 remains sub-maximal.
Steady state will be attained.
What sports are performed predominantly w/in the heavy domain?
Many endurance events
Incl. marathon
How long can heavy intensity exercise last if at a constant work rate?
~30-120 mins
Causes of fatigue from heavy exercise intensity
Combination of metabolite accumulation + substrate availability
HR in heavy exercise intensity
Delayed
Elevated to a steady state
Blood lactate for heavy intensity exercise
Elevated above resting values but a SS is attained.
Which is the ONLY domain in which VO2 max is attained?
Severe
In severe exercise what causes the VO2 to reach its Max?
The VO2 slow component
Do you see a steady state in severe exercise?
NO
What are the 2 reasons for why exercise in the severe domain is unique?
Has a wide range of work rates for which VO2 max can be attained.
Exercise tolerance is limited but also predictable
Duration for severe exercise intensity
2-~30 mins
Fatigue in severe exercise intensity
PCr depletion
Accumulation of fatiguing metabolites (Pi, H+)
HR in severe exercise intensity
No steady state
Continues to rise until max HR is achieved
Blood lactate in severe exercise intensity
No steady state
Continues to rise until exhaustion
Time to exhaustion for extreme exercise intensity domain
<90s
Fatigue reasons for extreme exercise intensity
PCr depletion + accumulation of fatiguing metabolites
HR for extreme exercise intensity
No steady state
Exercise stops before HR max is attained
Blood lactate for extreme exercise intensity
No steady state
Value may be surprisingly low due to short duration of exercise
What is a ‘step’ exercise test.
Refers to the way in which the load has been delivered.
Usually = an immediate ⬆️ in external workload from unloaded cycling to a higher power output, allowing us to track the responses of physiological variables as they adjust to the ⬆️ metabolic requirement.
Why do we perform 3-minutes of ‘unloaded’ exercise prior to the addition of the load?
Allows perf to establish a ‘baseline’ in physiological variables.
Can then correctly calculate extents to which the variables have changed.
Why do we select 6-minutes for the loaded exercise?
Should be long enough to determine the intensity domain from our physiological measures (except cases that are right on the borderline).
What can cycling economy tell us?
Higher gain is usually indicative of participant being above LT, where we will encounter the O2 uptake SC (an additional oxygen cost associated with additional motor unit recruitment).
How do we estimate the oxygen uptake slow component, and what does it indicate?
Value at end exercise - value at 3 mins of unloaded cycling.
Higher the number, the larger the slow component.
= Ind is consuming more O2 for a given work load than would have been predicted from the response to lower intensity exercise.
Which exercise intensity domain(s) result in a steady state in oxygen uptake, heart rate, and blood lactate?
Moderate and heavy (with the latter being a delayed and elevated steady state)
Which exercise intensity domain(s) result in the attainment of maximal oxygen uptake?
Severe - the only domain when completed to exhaustion which results maximal oxygen uptake.
Why is it important to account for exercise intensity when designing scientific experiments?
The body responds differently to different exercise intensities, with different mechanisms explaining fatigue. Inter-individual differences in the physiological responses can confound the results of experiments.
What underpins the variance in physiological responses at different intensities?
Occurrence of LT, GE threshold + MSS
What will happen to muscle PCr levels after exhaustive exercise above the MSS?
Sig reduction compared to resting levels.
What exercise would elicit the biggest reduction in muscle glycogen conc if it continued to exhaustion?
Exercise below LT
What would we expect blood lactate levels to be at the end of 6-min of moderate exercise?
Equal to resting levels
What is the upper boundary of the heavy domain?
Highest work rate where lactate stabilises.
