Exercise Phys 13: (deb Mitcheson) Limitations to exercise 1

Question 1

Equation for RQ?

Answer 1

RQ = VCO2/VO2

= 0.7 -> 1

Question 2

3 things which will alter/effect RQ assumptions

Answer 2

Hyperventilation -> excess CO2 produced

Exhaustive activity -> increased CO2 due to H2CO2 from lactate buffering

Gluconeogenesis -> formation of glucose through various pathways alters CO2/O2 ratio

Question 3

Define submaximal activity/exercise

Answer 3

activity that is less than maximal,
heartrate 50-80% of maximum
aerobic capacity (VO2 max) not reached
e.g. walking, cycling, jogging, swimming

Question 4

Define maximal activity

Answer 4

activity at which aerobic capacity (VO2 max) is reached

Question 5

What is meant by slow component of VO2 uptake kinetics?

Answer 5

• AT high power outputs, VO2 continues to increase
• More type II (less efficient) fibre recruitment
• Mechanistic basis of slow component unclear

-> Increase in O2 uptake only above lactate threshold

Question 6

What is meant by VO2 drift?

Answer 6

Upward drift observed even at low power outputs during prolonged, submaximal, constant power output exercise
- possibly due to an increase in ventilation

Question 7

What is VO2 max?

Answer 7

Maximal O2 uptake -> point at which O2 consumption no longer increases with an increase in exercise intensity

Best indicator of aerobic fintess (doesn’t predict endurance/performance)

Question 8

Limits to VO2 max?

Answer 8

1) Central physiological functions
- pulmonary diffusion
- cardiac outpit
- blood oxygen carrying capacity

2) Peripheral bodily functions
- muscle diffusion capacity
- mitohondrial enzyme levels
- capillary density

Question 9

What is EPOC?

Answer 9

Excess Post-exercise oxygen consumption

Vol. of O2 consumed immediately after exercise
-> i.e amount of O2 required to restore body to homeostasis

Question 10

Components of EPOC?

Answer 10

• Replenishment of energy sources e.g. ATP-PCr, glycogen, lactate clearing
• Re-oxygenation of blood
• Decrease in circulatory hormones e.g. (nor)adrenaline
• Decrease in body temp
• Decrease in ventilation and heart rate

Question 11

What is the lactate threshold? % of VO2max in trained/untrained?

Answer 11

Point at which lactate production increases (expressed as % of VO2 max
LT untrained ~55%
LT trained ~75%

Question 12

Cycle responsible for converting lactate back to pyruvate?

Answer 12

Cori cycle

in liver

Question 13

Structural explanation DOMS?

Answer 13

Structural damage

• indicated by muscle enzymes e.g. elevated creatine kinase in blood (conc. increase 2 - 10 times after heavy training)
• Onset of DOMS parallels onset of muscle ennzyme conc. increase
• Z-disk myofilament damage after eccentric work
• this muscle damage precipitates hypertrophy

Question 14

Inflammation explanation of DOMS ?

Answer 14

Connection between inflammation and soreness

• white blood cells conc. increases with soreness
• substances released initiate inflammation, damaged muscle cells attract neutrophils
• also stimulate pain nerves and macrophages to remove cell debris

Question 15

2 types of muscle cramp?

Answer 15

Exercise-associated muscle cramps (EAMC)

Heat cramps

Question 16

Causes of EAMC? Treatment?

Answer 16

Fatigue causes altered neuromuscular control and results in the excitation of muscle spindle and inhibition of Golgi tendon organ

Relief by stretching

Question 17

Causes of heat cramps? Treatment?

Answer 17

Often associated with large sweat + electrolyte losses, especially sodium + chloride

treatment high sodium solution, ice, massage (quinine??)