Ch.6 Flashcards by Jibran Qureshi

Decrements in muscular performance with
continued effort, accompanied by sensations of tiredness

Fatigue

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Inability to maintain required power output to continue muscular work at give intensity

(Also) Fatigue

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TF: Fatigue is reversible by rest

True

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4 major causes of fatigue (synergistic)

-Inadequate energy delivery/metabolism
-Accumulation of metabolic by products
-Failure of muscle contractile mechanism
-Altered neural control of muscle contraction

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Complex phenomenons of fatigue

-Type/Intensity of workout
-Muscle fiber type
-Training status,diet

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F: PCr depletion is used for __ term, __ intensity effort

Short
High

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TF: PCr gets depleted more slowly than ATP

False
Quickly

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What helps with deferring PCr depletion

Pacing

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Glycogen reserves are __ and get depleted __

Limited
Quickly

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PCr depletion __ w/ fatigue
Glycogen depletion is __ w/ fatigue

Coincides
Correlated

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Glycogen is depleted more quickly during __ few minutes of exercise and __ intensity work

First
High

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Metabolic By Products: from breakdown of PCr, ATP

P¡

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Metabolic By-Products: retained by body and increased core temperature

Heat

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Metabolic By-Products: product of anaerobic glycolysis

Lactic acid

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Metabolic By-Products: causes muscle acidosis

H+ accumulation

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What helps muscle pH, but not fully?

Buffers

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Drop in pH due to buffers

7.1 to 6.5

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What is inhibited if pH is less than 6.9?

Glycolytic enzymes
ATP synthesis

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What is prevented when pH is equal to?

Further glycogen breakdown

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How does heat alter metabolic rate?

-Increase rate of carbohydrate utilization
-Increase glycogen depletion
-High muscle temperature may impair muscle function

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Temperature where time to exhaustion is longest at?

11°C

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Temperature where time of exhuastion is shortest at is?

31°C

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Failure may occur at __ preventing muscle activation

Neuromuscular junction

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Possible causes of Neural transmission failure

-reduced ACh synthesis and release
-altered ACh breakdown in synapse
-increase in muscle fiber stimulus threshold
-altered muscle resting membrane potential

TF: Fatigue may inhibit _ release from SR

Ca2+

CNS: Conscious aspects of fiber recruitment

-Stress of exhaustive exercise may be too much -Person may be unwilling to endure more pain -Discomfort of fatigue is warning sign -Elite athletes learn proper pacing,tolerate fatigue

Interaction when making conscious decision to terminate activity

Between perception of effort and motivation

Feeling from exhaustive or high intensity exe4cise, especially during first-time

Muscle soreness

Soreness during and immediately after exercise

Acute soreness

Soreness one to two days later

Delayed-onset soreness

Acute muscle soreness disappears within several __ hours after exercise

Hours

What happens during Acute muscle soreness?

-Accumulation of metabolic by-products -Tissue edema -Edema triggers acute muscle swelling

Soreness ranging from stiffness to severe, restrictive pain

Delayed onset muscle soreness (DOMS)

Major cause of DOMS

Eccentric contractions

TF: Eccentric contractions are caused by increase in blood lactate concentrations

False

Structural damage to DOMS is nice ages by __ in blood

Muscle enzymes

Onset of DOMS __ onset of increasing muscle enzymes in blood

Parallels

Structural damage: concentrations increase __to__ times after heavy training

2 to 10

How are sarcomere Z-disks anchoring points of contact for contractile proteins?

-They transmit force when muscle fibers contract -Z-disk, myofilament damage seen after eccentric work

Muscle damage __ hypertrophy

Precipitates

TF: Inflammation and soreness are connected

True

Inflammation: __ blood cells defend body against foreign materials and pathogens

White

TF: When sore, WBC count decreases

False Increases

Type of immune system cell that removes cell debris

Macrophages

Inflammation: What cells attract neutrophils?

Damaged muscle cells

What do neutrophils release to stimulate pain nerves?

Attractant chemicals, radicals

Sequence of events in DOMS: (1) __tension In muscle triggers __ damage to muscle, cell membrane

High Structural

Sequence of events in DOMS: (2) Membrane damage disturbs __ __ in injured fiber

Ca2+ homeostasis

Inhibits cellular respiration and activates enzymes that degrade Z disks

Membrane damages disturbing Ca homeostasis

Sequence of events in DOMS(3): After a few hours, circulating neutrophils __

Increase

Sequence of events in DOMS(4): Products of macrophage activity, __ __ accumulate

Intracellular contents

DOMS: Intracellular contents include ___(3)

Histamine, Kinins, K+

DOMS: Stimulates pain in free nerve endings

Intracellular contents

Sequence of Events in DOMS(5): Fluid and electrolytes shift into the area, creating. __

Edema

TF: DOMS increases muscle force generation

False Reduced

Three factors for loss of strength

– Physical disruption of muscle – Failure in excitation–contraction coupling (apparently, most important) – Loss of contractile protein

DOMs must be __ for effective training

Reduced

3 strategies to reduce DOMS

– Minimize eccentric work early in training – Start with low intensity and progress slowly – Start with high-intensity, exhaustive training (soreness bad at first, much less later on)

Factors associated with DOMS are potentially important for stimulating

Muscle hypertrophy