Chapter 6 Flashcards
These two definitions represent what term?
- “Decrements in muscular performance with continued effort, accompanied by sensations of tiredness”
- Inability to maintain required power output to continue muscular work at given intensity”
Fatigue
T/F: fatigue is reversible by rest
True
What are the 4 major causes of fatigue? Which of the 4 are peripheral fatigue and central fatigue?
- Inadequate energy delivery/metabolism
- Accumulation of metabolic by-products
- Failure of muscle contractile mechanism
- Altered neural control of muscle contraction
1-3: Peripheral
4: Central
_____ depletion coincides with fatigue.
PCr
Which energy system is used for short-term, high-intensity effort?
PCr
PCr gets depleted more quickly than total ____.
ATP
T/F: Pacing helps defer PCr depletion.
True
_____ reserves are limited and get depleted quickly.
Glycogen
Glycogen depletion is correlated with ______.
Fatigue
T/F: Glycogen depletion is related to total glycogen depletion.
True
Glycogen is depleted more quickly with ______ intensity.
High
Glycogen is depleted more quickly during first few _____ of exercise.
Minutes
T/F: Depletion of glycogen is different in various muscle groups.
True
Are activity specific muscles depleted the slowest or fastest?
Fastest
What metabolic by-product is derived from rapid breakdown of PCr, ATP?
Pi
Which metabolic by-product is retained by body, core temperature increases?
Heat
Which metabolic by-product is a product of anaerobic glycolysis?
Lactic acid
Which metabolic by-product causes muscle acidosis?
H+ accumulation
What is the chemical equitation for H+ accumulation?
H+ + lactic acid —> lactate + H+
T/F: Lactic acid accumulates during brief, low intensity exercise.
False; high intensity exercise
When lactic acid is not cleared immediately, it converts to ________.
Lactate + H+
What causes decrease in muscle pH (acidosis)?
H+ accumulation
What helps muscle pH but not enough?
Buffers
Buffers minimize drop in pH (____ to ____, not to ____).
7.1 to 6.5, not to 1.5
What survives the presence of buffers but don’t function well?
Cells
If pH <___, inhibits glycolytic enzymes, ATP synthesis.
6.9
If pH = ___ , prevents further glycogen breakdown
6.4
____ alters metabolic rate.
Heat
How does heat alter metabolic rate? (IIH)
- Increase rate of carb utilization
- Increase glycogen depletion
- High muscle temperature may impair muscle function
Time to fatigue changes with _________.
Ambient temperature
Time to exhaustion is longest at ___ C*
11
Time to exhaustion is shortest at ____ C*.
31
T/F: Muscle precooling prolongs exercise
True
If failure occurs at ________, it can prevent ______ activation.
Neuromuscular junction ; muscle
What are the 4 possible causes of failure occurring at neuromuscular junction preventing muscle activation?
- Reduced ACh synthesis and release
- Altered ACh breakdown in synapse
- Increase in muscle fiber stimulus threshold
- Altered muscle resting membrane potential
Fatigue may inhibit ____ release from SR.
Ca+2
T/F: CNS undoubtedly plays role in fatigue but not fully understood yet.
True
Fiber recruitment has _____ aspect.
Conscious
Energy delivery/metabolism is related to depletion of what?
PCr & glycogen
Metabolic by-product is related to which acid & element?
lactic acid & H+
Regarding psychobiological aspects, conscious decision is used to terminate ____.
Activity
In psychobiological aspects, there is an interaction between ______ and ______.
Perception of effort & motivation
What is a psychobiological strategy to reduce fatigue?
Self-talk
What are the 8 factors that influence fatigue during exercise? (IDFTADAH)
- Intensity
- Duration
- Fiber type of involved muscles
- Training status
- Age
- Diet
- Ambient temperate
- Humidity
Which soreness is during and immediately after exercise?
Acute
Which soreness is one to two days later?
Delayed-onset soreness
Edema —> ________
Acute muscle swelling
Acute muscle soreness disappears within several _____ after exercise.
Hours
T/F: DOMS can range from stiffness to severe, restrictive pain.
True
What is a major cause of DOMS?
Eccentric contractions
What is an example of DOMS occurring via eccentric contractions?
Level run pain < downhill run pain
Structural damage is indicated by _______ enzymes in blood.
Muscle
_______ are anchoring points of contact for contractile proteins.
Sarcomere Z-disks
Muscle damage precipitates _______.
Hypertrophy
________ and soreness are connected.
Inflammation
_____ blood cell count increases with soreness.
White
Substances released initiate ________.
Inflammation
_______ remove cell debris.
Macrophages
T/F: High tension in muscle can lead to structural damage to muscle, cell membrane.
True
What is the sequence of events in DOMS?
- High tension in muscle —> structural damage to muscle, cell membrane
- Membrane damage disturbs Ca+2 homeostasis in injured fiber
- After a few hours, circulating neutrophils increase
- Products of macrophage activity, intracellular contents accumulate
- Fluid and electrolytes shift into the area creating edema.
___—> reduced muscle force generation
DOMS
Loss of strength results from what 3 factors?
- Physical disruption of muscle
- Failure in excitation-contraction coupling (apparently most important)
- Loss of contractile protein
T/F: Must reduce DOMS for effective training
True
What are 3 strategies to reduce DOMS?
- Minimize eccentric work early in training
- Start with low intensity and progress slowly
- Start with high-intensity, exhaustive training
Factors associated with DOMS are potentially important or stimulating __________.
Muscle hypertrophy
What is likely necessary to maximize training response?
DOMS
