Week 5 - Speed Endurance Training Flashcards
Define speed endurance
Ability to maintain a high speed for a prolonged period of time + to recover speed following short recovery periods.
Sports where speed endurance is a key fitness component
Track + field — 200-800m
Track Cycling — 500-1000m
Swimming — 50-200m
Value of speed endurance in team sports
25-40 sprints in a game, 2-4 secs
Work:Rest – 1:6
How long do bouts last for speed endurance production training
10-40s
Perf at max or near Max intensity
What is recovery/rest like for speed endurance production training
More than 5 times the exercise bout duration.
How long do bouts last for speed endurance maintenance training
5-90s
What is recovery/rest like for speed endurance maintenance training
Shorter rest period between bouts
1-3 times exercise duration.
Speed endurance production training vs speed endurance maintenance
Sessions per week
3 - 3
Speed endurance production training vs speed endurance maintenance
Weeks
3 - 3
Speed endurance production training vs speed endurance maintenance
Bouts per session
6-8 – 6-8
Speed endurance production training vs speed endurance maintenance
Recovery duration
120s - 40s
Describe a typical speed endurance training programme
Duration: 4-8 weeks
Sessions: 3-4
No. of bout reps per session: 4-12
Duration of exercise bout: 30s
Intensity of exercise bout: 90-100% of max speed
Recovery between bouts: 4-6mins
Energy Systems contributions to 30s Wingate test
PCR = approx 28% of total ATP req.
Oxidative phosphorylation contributes around 16%.
If you extended the sprint beyond 30s, then the contribution from aerobic metabolism would further ⬆️.
Remaining 56 % of ATP demand for 30s all out sprint, is provided by anaerobic glycolysis.
== Glycolysis = primary source of ATP during this prolonged sprint activity.
Why isn’t heavy reliance on anaerobic glycolysis sustainable for a long time?
Limited glycogen stores
Prod. of LA = ⬆️ H+ = Muscle acidosis
What does muscle acidosis inhibit?
Glycolysis + perhaps the contractile apparatus.
Diff in amount speed endurance training vs endurance training increases muscle glycogen stores
SET == 28%
End. training = 17%
By how much does SET ⬆️ muscle buffering capacity
8%
How does SET ⬆️ muscle buffering capacity
By ⬆️ no. of intramuscular buffers
+
⬆️ no. of H+ transporters (exporting H+ outside muscle + into bloodstream)
What are the intramuscular buffers?
Carnosine protein
Sodium phosphate
What type of transporters also transport H+ out of muscle fibre
Membrane embedded transporters
What buffer is there in the blood to neutralise H+
Bicarbonate buffer
What are 2 of the membrane transporters responsible for moving H+ out of muscle fibre?
Monocarboxylate transporter / MCT
Sodium-hydrogen exchanger / NHE
- Evidence suggests these are ⬆️ as a result of SET.
When is there a -ive membrane potential of -70milivolts?
Resting membrane pot.
When muscle fibre hasn’t been stimulated to contract.
Charge wise, what does it mean when there’s a -ive membrane potential of -70 millivolts?
LOWER charge inside muscle
Describe ion distribution in resting conditions
IN fibre = High conc of K+
OUTSIDE fibre = High conc. of Na+
What is the resting membrane potential caused by?
Imbalance in no. of ions inside + outside fibre
What happens when a signal arrives at the muscle fibre from a neurone
Electrical current causes membrane Na+ channels to OPEN.
What happens once Na+ channels are open?
Na+ move into muscle fibre, causing membrane pot. to ⬆️ to a +ive 30 milivolt charge == AP.
+ive charge triggers neighbouring Na+ channels to open, leading to sodium influx further along membrane. — How AP is able to propagate along the sarcolemma + down T tubules.
What happens if membrane is stimulated when not at a -ive 70 millivolt charge
AP won’t occur as readily or won’t be as strong, potentially inhibiting the propagation + strength of AP.
— Inhibiting contraction force — a loss of muscle excitability.
What is the 1st step to returning membrane pot to resting levels
Opening of K+ channels so that K+ can flow from inside to outside fibre.
What happens when K+ flows from inside to outside muscle fibre?
Brings pot. down to -ive 100 millivolts, overshooting the -ive 70 millivolt target.
For this reason, a Na+/K+ ATPase pump is present in memb. — To move K+ back into fibre + Na+ out of fibre — restoring -ive 70 millivolt memb. pot.
What happens when APs repeatedly arrive at muscle at a maximal rate?
Accumulation of K+ outside muscle fibre causes reduced muscle excitability
What does SET do to for the Na+/K+ ATPase pumps?
⬆️ the no. of them
What does SET do in relation to adapt of mitochondria?
⬆️ mit. mass
What does SET do in relation to adapt of enzymes?
⬆️ no. + activity of important enzymes in Krebs cycle + ETC. These incl:
- Citrate synthase, 1st enzyme of Krebs cycle.
- Cytochrome C oxidase, important enzyme in ETC.
What is perf. during repeated sprint bouts partly dependent on?
Ind. ability to replenish their PCr stores before next sprint.
What does replenishing PCr require?
ATP (mostly provided by aerobic system)
How much lactate is shuttled to type 1 muscle fibres?
What happens there?
Where does the rest of the lactate go?
Around 75-80%
Oxidised by mit. to form glucose.
Other portion of lactate is shuttled out of muscle via bloodstream to heart + liver where its converted to glucose.
– Then released back into bloodstream + taken up by muscle.
Lactate shuttle hypothesis
Means by which lactate can act as a substrate for ATP prod. by refuelling muscle w/ glucose that can enter glycolysis.
What are the ways in which SET improves the lactate recycling process
⬆️ abundance of mit. = ⬆️ the oxidation of lactate w/in muscle itself.
⬆️ movement of lactate out of muscle due to larger no. of cap. available.
Give a summary of physiological adapt. to SET
⬆️ in muscle glycogen
⬆️ glycolytic enzymes
⬆️ buffering capacity + H+ transporters
⬆️ Na+ K+ ATPase
⬆️ in muscle capillerization + oxidative capacity
⬆️ type 2a muscle fibres
What does SET improve in already trained endurance athletes
Economy
VO2 max
Endurance perf (3-10km)
How does SET improve endurance performance
⬆️ VO2 max
⬆️ exercise economy
⬆️ speed of VO2 kinetics
⬆️ lipid metabolism
How does SET improve endurance performance
Explain ⬆️ lipid metabolism
⬇️ utilisation of limited glycogen stores + red. prod. of LA
Describe a training session being an example of Speed endurance PRODUCTION
12 reps
30 s running at 100% max speed
6 min recovery between reps
Fibre type changes following SET
⬆️ type 2
⬇️ type 1
During a 30-s all-out cycle sprint, 56% of ATP is provided by the…
Glycolysis system
Following SET there is an increase in muscle carnosine concentration. This is important because it…
Buffers H+
Why is there a negative muscle fibre membrane potential at rest?
More +ively charged ions OUTSIDE muscle fibre
What does an accumulation of K+ outside the muscle fibre result in?
⬇️ muscle excitability
An increase in Na+-K+ ATPase pumps after SET will help maintain muscle excitability by…
Preventing accumulation of K+ outside muscle fibre
What does SET result in in relation to capillary density
⬆️ capillary density + capillary-fibre ratio
What has SET been shown to improve?
Repeated sprint performance
Individual sprint performance
Endurance performance
Which of the following does not contribute to the improved endurance performance after SET?
a. Increased mitochondrial number
b. Increased cardiac output
c. Improved economy
d. Speeding of VO2 kinetics
b. Increased cardiac output
