Extreme exercise

Question 1

energy delivery (specifically oxygen)

Answer 1

at onset of exercise there is lag before oxygen delivery increases
-leads to oxygen deficit and oxygen debt

Question 2

during the initial two minutes of exercise the body relies on ____ and ____ glycolysis

Answer 2

“stored energy”

anaerobic glycolysis

Question 3

glycolysis producing ATP

Answer 3

rather inefficient,
every glucose –> only produce 2 ATP for one
(anaerobic)

Question 4

anaerobic glycolysis and oxidative phosphorylation

Answer 4

much slower generate large amounts of (30) ATP for the cell per glucose molecule

Question 5

ATP in the cells always

Answer 5

5 ATP

Question 6

phosphatecreatine (PCr) in the cells always

Answer 6

10-50 molar

Question 7

“stored energy” used at the beginning:

Answer 7

• ATP –> ADP + Phosphate + Energy (ATP used up so..)
• ADP + PCr –[Creatine kinase]–> ATP + Creatine

PCr used up tho so ADP accumulates___
ADP+ADP–Adenylate kinase–> ATP+AMP

Question 8

Built up of ADP, AMP and phosphate from energy stores =

Answer 8

stimulate metabolic pathways involved in energy productions (krebs cycle etc ) via negative feedback

Question 9

Anaerobic phase (non oxidative) of energy release: USING GLYCOLYSIS

Answer 9

-2 ATP / glucose molecule
- muscles fibres store glycogen about 300-400g
- substrate enters glycolysis at 2 points
-glycogenolysis = glucose-1-phosphate
-converted to glucose-6-phosphate
-uptake of glucose from blood by GLUT4, glucose enters glycolysis pathway
==> 2 pyruvate molecules formed produced.
pyruvate converted to lactic acid/lactate
-H+ from lactic acid lowers cells pH and leads to muscle fatigue

Question 10

aerobic phase (oxidative) of energy release

Answer 10

• oxygen delivery to tissue increases, energy production via oxidative phosphorylation is stimulated
• slower but mote efficient = 30 ATP / glucose molecule
• glucose sourced from blood(GLUT4), following breakdown of glycogen from liver
• lactate is converted back into pyruvate feeds oxidative phosphorylation
• TypeIIX fibres release lactate into circulation (can enter other muscles or to liver to generate fresh glucose)

Question 11

extended periods of exercise:

Answer 11

lactate and alanine: used by liver –> new glucose
During exercise: lactate can be released from non exercising muscles. body acts to redistribute glycogen stores
-mobilisation of non-muscle lipids (increase in circulating fatty acids) taken up by muscle
-breakdown of triaglycerols stored in muscle

Question 12

muscle fatigue:

Answer 12

inability to maintain a described power output

-decline in force and velocity of muscle shortening

Question 13

muscle fatigue: central fatigue

Answer 13

minor factor in trained exercise

‘this is starting to hurt’ ‘mind over matter’

Question 14

muscle fatigue: peripheral fatigue

Answer 14

at the level of the muscle fibre- various factors

Question 15

muscle fatigue: high-freq fatigue

Answer 15

alteration in cell Na/K (inside high Na low K normally) balance
-particularly relevant to type 2 fibres

Question 16

muscle fatigue: low-freq fatigue

Answer 16

reduced release of Ca2+ from sarcoplasmic reticulum (more apparent at low frequency stimulation, type1 fibres)

Question 17

muscle fatigue: ATP depletion

Answer 17

Intense stimulation can cause large drops in ATP near sites of cross-bridge formation and ATPases.
normally 5 mM to 2mM,

Question 18

muscle fatigue: lactic acid build up

Answer 18

high rates of lactate production lead to cellular acifdifcaiton

Question 19

muscle fatigue: glycogen depletion

Answer 19

losing good source of glucose production

Question 20

considerations for maintaining aerobic activity:

Answer 20

1) uptake of oxygen by lungs - pulmonary ventilation
2) oxygen delivery to muscle - blood flow and O2 content in blood
2) oxygen extraction by muscle - depends on oxygen delivery and diffusion gradient

Question 21

maximal oxygen uptake VO2 Max

Answer 21

As work done (power output) increases reach a point where Oxygen delivery can’t meet the demand. Oxygen consumption plateaus.

SO VO2 max =maximal oxygen uptake is an index of ability to generate aerobic power

Question 22

to increase VO2 max or adapt the body:

Answer 22

1) intensity of activity must be higher than a critical threshold
2) each period of activity must be of a sufficient duration
3) repetition of activity
4) rest period to allow adaptions to occur

Question 23

training increases the

Answer 23

ability to deliver oxygen to tissues

Question 24

maximum rate of oxygen uptake =

Answer 24

optimal cardiac output X diffusion gradient for oxygen in muscle

Question 25

maximising oxygen content in arterial blood: possible options

Answer 25

1) increase maximal alveolar ventilation
2) increase pulmonary diffusing capacity
3) improve ventilation/perfusion matching
4) increase haemoglobin concentration (ISSUES, more RBC increased velocity of blood)

Question 26

maximising cardiac output.

cardiac output =

Answer 26

heart rate X stroke volume

• HR fixed, so increase stroke volume
• max CO can increase by ~40%
• – increased plasma volume

Question 27

maximising oxygen extraction:

Answer 27

• formation of new microvesseld mainly capillaries in muscles
• -allows an increase blood flow to muscle
• -Increased surface area for diffusion
• -Reduced distance for diffusion to muscle fibres

increase in mitochondrial content in skeletal muscle fibres

• -promotes oxygen extraction form blood
• -increased capacity to oxidise fat

Question 28

high altitude training: 3 models

Answer 28

• Live high train high
• live low train high
• live high train low

Question 29

Live high train high (LHTH)

Answer 29

• effectiveness is not conclusive
• popular
• less oxygen so can’t train at same intensity as you would at sea level,
• increased chance of mountain sickness
• heat acclimatisation

Question 30

live low train high (LLTH) OR Intermittent hypoxic training (IHT)

Answer 30

live in normal conditions, training subjected to hypobaric conditions

• no haematological benefits, but may see benefits from muscle adaptions
• used as a preacclimisation technique before ascending to reduce risk of AMS

Question 31

live high train low (LHTL)

Answer 31

BEST OPTION?

• need to live at 2000m for 14-16 hours per day for 19-20 days to sustain erythropoietic (RBC production) effects
• Athletes gain benefits of physiological adaptations and can maintain normal intensity of training.
• Studies show mixed results.
• Disadvantage – travel time to and from altitude

Question 32

ergogenic aids:

Answer 32

a perfomance enhancer that gives you a mental or physical eye while exercising or competing
-range from caffeine and sports drinks to illegal substances

Question 33

beetroot juice supplementation

Answer 33

enhanced skeletal muscle function