factors affecting human performance - week 10

Question 1

what elements of the environment can affect performance? (3)

Answer 1

altitude

heat

humidity

Question 2

what elements of the CNS affect performance ?(2)

Answer 2

arousal

motivation

Question 3

what parts of aerobic energy production effect performance? (1)

Answer 3

glycolysis

Question 4

what parts of aerobic sources effect performance? (4)

Answer 4

VO2 max

CO

O2 delivery/ extraction

mitochondria

Question 5

what elements of strength/skill affect performance? (2)

Answer 5

practice

genetics

Question 6

where does central fatigue occur ?

Answer 6

brain + spinal cord

Question 7

where does peripheral fatigue occur ?

Answer 7

muscles and peripheral nerves

Question 8

what are some advantages and disadvantages of studying muscle fatigue through full body movement ?

Answer 8

+ all physiological mechanisms present

+ all fatigue types can be studied

• produces correlative data - hard identify cause+ effect
• hard locate specific mechanism

Question 9

what are some advantages and disadvantages of studying muscle fatigue through isolated muscles ?

Answer 9

+ central fatigue eliminated

+ dissection is simple

• inevitable extracellular O2 , CO2, K+, lactic acid
• mechanisms are based by presence of extracellular gradients

Question 10

what are some advantages and disadvantages of studying muscle fatigue through isolated fibres?

Answer 10

+ only one fibre type present

+ force and other changes can be unequivocally correlated

• prone to damage at physiological temperatures
• analysis of metabolites is hard due small size

Question 11

what are some advantages and disadvantages of studying muscle fatigue through skinned fibres ?

Answer 11

+ metabolic and ionic changes can be associated with fatigue in isolation

+ precise solutions can be studied in isolation

• may lose important intracellular constituents
• relevant metabolites to study must be identified in other systems

Question 12

what can cause central fatigue ?

Answer 12

reduction of motor units activated and firing frequency

Question 13

how can the CNS arousal alter the state of fatigue ?

Answer 13

facilitates motor unit recruitment

Question 14

what are the neural factors of peripheral fatigue ? (3)

Answer 14

sarcolemma and transverse tubules :

alter muscle membrane to conduction and action potentials

inability for Na+/K+ pump to maintain AP

Question 15

what are the mechanical factors of peripheral fatigue ?

Answer 15

cross bridge cycling and tension development -
- arrangement of actin + myosin
- Ca+ binding to troponin
- ATP availability

high H+ concentration -
- reduced force per cross-bridge
- inhibit release of Ca+ from SR