Chap. 6- Fatigue Flashcards
What is critical power?
The link between energy expenditure and fatigue
What factors affect critical power?
Overload, lack of oxygen, push to muscle failure, sleep hygiene, hydration, stress, nutrition.
What are 2 definitions of fatigue?
- Decrease in muscular performance with continued effort, sensations of tiredness (Working up to muscle failure)
- Inability to maintain power output to continue muscular work (Muscle failure)
How is fatigue reversed?
Rest
What complex(exercise) factors influence fatigue?
- Type of exercise and intensity
- Muscle fiber type
- Training status
- Diet
What are 4 CAUSES of fatigue? ***
- Inadequate metabolism
- Lactate threshold
- Failure of muscle contraction
- Altered neural control
What’s an example of failure of muscle contraction?
Cramp
What’s an example of altered neural control of muscle contraction?.
Flight, pass out
What helps defer Pcr Depletion?
Pacing
What can cause Pcr depletion?
Phosphate accumulations
What coincides with Pcr depletion?
Fatigue
True or False: Glycogen is depleted more quickly during the first few minutes of exercise.
True
What muscle fibers are lla?
Moderate Exercise Intensity
What muscle fibers are llx?
Maximum intensity exercise
What muscle fibers are recruited 1st?
Type I muscle fibers
What are two muscles that have different muscle depletion?
Gastric and Soleus
Two factors of activity specific muscles?
Depleted fast, used first and longest for task
True or False: Muscle glycogen is sufficient for prolonged exercise.
False- insufficient
Where is glycogen used from first?
Muscles
After muscle glycogenolysis where is it utilized from?
Liver
Muscle glycogen depletion + hypoglycemia=?
Fatigue
What does Pi stand for?
Inorganic Phosphate
Where does Pi (Inorganic Phosphate) get made from?
Rapid breakdown of Pcr and ATP
What is lactic acid a product of?
Anaerobic glycolysis
What causes muscle acidosis?
H+ accumulation
What is acidosis?
Low muscle Ph
What accumulates during high intensity exercise?
Lactic Acid
Process of lactic acid
Lactic acid accumulates then converts to lactate acid + H+, which lowers muscles Ph creating acidosis.
What helps muscle Ph?
Buffers but not enough
How does acidosis affect muscle?
Function
What Ph level affects ATP synthesis?
< 6.9
What substances/ factors can help endurance and can change lactate threshold?
Caffeine, B-Vitamins (catalyst), Carb loading, Training
What’s a negative effect of impaired mitochondrial function?
Issue with Recovery, Oxidative ATP Production
How long does recovery take for a Sprinter?
25-30 min
What issues occur with neural transmission failure?
- Delay or muscle failure
- No activity from NMJ
- Reduced ATP
Why does neural transmission fail?
- Reduced ACH synthesis and release
- Increase muscle fiber stimulus threshold
- Altered resting membrane potential can change
What can fatigue inhibit?
Ca+ release from SR
What happens when Ca+ release is inhibited from SR?
Interrupts muscle contraction
How does CNS play a role in fatigue?
- Stress of exercise may be too much
- Unwilling to endure more pain
- Discomfort of fatigue warning sign
- Learn proper pacing, tolerate fatigue
Psychological aspect part of fatigue?
- Conscious decision to stop
- Self-talk to reduce fatigue
What factors affect Neural Transmission?
- CNS
- Psychobiological aspect
- Heat
- Critical Power
- Muscle Soreness
How does heat affect fatigue?
- Alters metabolic rate
- Increases carb utilization
- Speeds up glycogen depletion
- May impair muscle function
- Time to fatigue changes
What is Critical Power?
Tolerable duration of high intensity exercise
When does Critical Power increase?
With endurance and HIIT
When does Critical Power decrease?
Age, Chronic disease, hypoxia, performance in events lasting 2-min to 2-hours.
Why do muscles get sore?
- Exhaustive
- High intensity for the first time
- Fatigue
- Lactic Acid
- Muscle Failure
- Muscle tearing
- Didn’t heat up properly
- Eccentric
- Overload
- New exercises
- Injury
- Atrophy (had injury and try to workout again)
DOMS time period
24-48 hours later
Why do you get sore during or immediately after strenuous exercise or novel exercise?
-Tissue Edema
- Accumulation of metabolic by-product; changing the acidity
What causes DOMS?
- Eccentric contractions
- Structural damage
- Inflammation
How does muscle damage (structural damage) occur -cellular level?
- Increase in enzymes, through blood testing- X 10 times
- Parallels DOMS
- Z- dish damage after eccentric work ***
What does muscle damage precede?
Hypertrophy, muscle increase
What increases in the blood during inflammation?
White Blood Cell count
Sequence of DOMs?- How edema occurs?
- High intensity**
- Structural damage**
- Homeostasis of Ca+ is disturbed
- Inhibits cellular respiration
- Degrades Z-disk
- Circulating Neutrophils
- Pain free nerve endings, eccentric
- Fluids and electrolytes- Edema
DOMS and Performance: (LOSS)
- LOSS of Force***
- LOSS of Strength ***
- LOSS of contractile proteins
How to decrease DOMS?
- Effective training
- Minimize eccentric work early in training
- Start low-intensity
- High-intensity first, soreness first, less later
What is EAMC?
Exercise Associated Muscle Cramps
How does EAMC occur?
- Overwork muscle
- Lack of conditioning
- Electrical stimulation
How to reduce EAMC?
- Stretching
- Active recovery
- Change excitatory property of motor neuron
What is central origin of neuromuscular control?
Hyperexcitable motor neurons FROM ACTIVITY
What is peripheral origin?
Spontaneous discharges of motor neurons- getting hit, or stopping awkwardly.
Risk factors of cramping?
- Hx of cramping
- Age
- Increased exercise intensity & duration
- Lack of fitness
What is lost during electrolyte depletion?
- Sodium
- Chloride
How do you get heat cramps?
- Loss of electrolytes- sodium and chloride
Treatment of electrolyte depletion? ***
- High sodium intake- pickle juice/electrolytes
- Chloride
