Physiology of Intermittent Sports

Question 1

What tools can be used to assess demands during performance?

Answer 1

GPS Monitoring

Prozone (cameras)

Question 2

What physical demands should be considered during performance?

Answer 2

• Implications of pacing strategies due to ever-changing gameplay
• Many high-intensity running and sprinting in top players, therefore this declines fast
• Demands are also position specific

Question 3

Football specific crap that was on the board

Answer 3

• 10-12km covered during a match
• fatigue develops in all players
• Longer high-intensity periods of running make it more likely to win
• tactics can be developed specific to players
• different tactics, different demands (4-5-1 vs 4-4-2)

Question 4

How can metabolic demands be measured during gameplay?

Answer 4

Masks obvs cant be used so use Polar HR monitoring, which can be integrated with GPS monitoring

Question 5

What is the correlation between ATP resythesis and capacity?

Answer 5

From PCr to Aerobic, rate is highest in PCr but capacity is highest in aerobic

Question 6

How can VO2 be monitored during gameplay?

Answer 6

During an incremental TTE, record HR during test to estimate VO2 on the field!

Question 7

What happens to BLa during play?

Answer 7

increaes during matchplay (4010 mMoL), indicating reliance on anaerobic glycolysis

Lactate can be oxidised into substrate, allowing it to continue for longer, however this is at a slow rate.

Question 8

What happens to PCr during high-intensity exercise?

Answer 8

Declines and is then resynthesised during recovery
PCr recovery significant is linked to muscle O2 recovery during exercise
Therefore aerobic is important during recovery

Question 9

What happens during Purine Nucleotide Metabolism (ATP degradation)?

Answer 9

ATP is broken down into 2 phosphates to create energy
myokinis attach these together
Ammonia is produced within bloodstream

Question 10

What happens to Ammonia during a match?

Answer 10

Venous blood ammonia production increases for the first half, lowers slightly during half time and then increases again during second half
As ammonia can cross the blood-brain barrier, this is a cause on central fatigue

Question 11

How can fatigue development be measured?

Answer 11

Through GPS monitoring or repeated (30m) sprints

MVC - time taken to strap in etc can make less accurate

Question 12

What are the sites of fatigue?

Answer 12

Central - CNS (brain, spinal cord, motor neurons

Peripheral - peripheral nerves (alpha motor neurons), neuromuscular junctions, muscle fibres

Question 13

How to measure global and peripheral fatigue?

Answer 13

Global - MVC

Peripheral - potentiated twitch

Question 14

What are the main metabolic changes during high-intensity intermittent exercise?

Answer 14

• Increased oxidative energy metabolism

- Lower aerobic glycolysis

Question 15

What is the fundamental mechanism of excitation contraction coupling?

Answer 15

Depolarization (excitation) of muscle fibre

• nerve impulse travels down T-tubules, releasing calcium from SR
• Calcium binds to troponin, exposing ctive sites on actin
• permits strong binding state between actin and myosin, causing contraction

Question 16

What are the consequences of increased plasma K+?

Answer 16

• Increased K+ in interstitial fluid surrounding cells
• Membrane becomes depolarized (effects on action potential)
• Action potential amplitude is induced
• inactivation of voltage-gated Na+ channels

Question 17

What are the consequences of Ca2_ release from SR?

Answer 17

• Impaired (slower) Ca2+ reuptake following exercise
• impaired muscle relaxation
• release to cause contraction but must be reuptaken by SR or stiffness occurs

consequence - impaired muscle contraction

Question 18

What are the benefits of greater fat oxidation?

Answer 18

• Greater ATP production than glycogen
• Spares glycogen stores
• Massive reserves

Question 19

What are the implications of anaerobic production?

Answer 19

• Muscle glycogen and PCr reserves are limited, advantageous to preserve
• Accumulation of Pi, ADP and H+ in muscles is linked to muscular fatigue
• Oxidative metabolism is key in recovery

Question 20

Na/K+ pumps can be improved with training, what are the implications of this?

Answer 20

Increase K+ in cells may limit K+ in interstitial fluid which might

• delay progressive membrane depolarization
• delay lower action potential amplitude
• delay fatigue

Question 21

What are the benefits of fast twitch fibres during intermittent exercise type 2a

Answer 21

• faster nerve conduction
• faster muscle contraction
• greater PCr and glycogen stores (anaerobic energy substrates)
• more anaerobic enzymes
• greater SR and Ca2+ stores, faster calcium release
• larger cross-sectional area - more myofibrils
• more forceful contractions