Factors Affecting Performance Flashcards
1
Q
2 Sites of Fatigue
A
- central
- peripheral
(or both)
2
Q
Peripheral Fatigue
:Excitation Contraction Coupling:
2 Hypotheses
A
- depletion hypothesis
- accumulation hypothesis
3
Q
2 Factors Affecting Performance
A
- fatigue
- Muscle recruitment
4
Q
Fatigue
A
inability to continue a specified task, which is reversible with rest
5
Q
Fatigue depends on:
A
- Type of exercise performed
- muscle fiber types involved
- pt’s fitness and nutritional status
6
Q
Mechanisms of Central Fatigue
A
- decr functional motor units or decreased frequency of firing
- inhibitory input to neurons in brain from muscle afferents
- psychological (motivation)
- serotonin
7
Q
Components of Peripheral Fatigue
A
- neuromuscular junction
- muscle cell membrane
- excitation contraction coupling (primary site of fatigue)
8
Q
Order of Muscle Recruitment
A
Type I, IIa, IIx
9
Q
Type I fibers
A
- recruited first
- provide tension to about 40%VO2 max
- aerobic metabolism
10
Q
Type IIa
A
- recruitment if O2 not available to utilize type I
- recruited if intensity reaches 40-75% VO2 Max
- aerobic and anaerobic metabolism
11
Q
Type IIx
A
- recruited if O2 delivery not sufficient for type I & IIa fibers
- recruited at ~75% VO2 max
- anaerobic glycolysis
12
Q
High H+ Concentration can cause:
A
- decr force/crossbridge
- decr force for given Ca++ concentration
- inhib Ca++ release from SR
- Disruption of Na-K pump
- inhibition of PFK
13
Q
Depletion Hypothesis
A
depletion of ATP, PC, & Glycogen
14
Q
Accumulation Hypothesis
A
-accumulation of ammonia, phosphate, lactate, H+
15
Q
Long Term Activities
A
- 1-4 hours
- ability of liver & muscle to provide glucose
(change glycogen–>glucose)
