Exercise physiology Flashcards
T/F adult muscle fibers are postmitotic
T
T/F Skeletal muscle exhibits remarkable plasticity in structure and function
T
postmitotic
no cell division after maturation
Structural plasticity
manifests as changes in fiber size (atrophy ↔ hypertrophy)
functional plasticity
involves the interconversion of muscle fiber types and/or
modulation of mitochondrial density
Type I (“slow twitch”) fibers are fatigue-resistant due to their?
high mitochondrial density
Type I (“slow twitch”) fibers rely on ________ _______ for ATP and are thus energy-efficient.
aerobic respiration
__________ (“fast twitch”) fibers exhibit rapid cross-bridge cycling, which enables strong contractions that are fueled
by _________ _________.
Type II , anaerobic respiration
Type II fibers develop as either fast ________ ________
(FOG; Type IIa) or fast __________ (FG; Type IIx) subtypes.
oxidative glycolytic, glycolytic
Resistance exercise
(strength training) involves short bursts of intense activity.
Skeletal muscle adaptation in response to resistance training results in?
1) hypertrophy
2) the interconversion of Type IIa → Type IIx fibers
3) an increase in nuclei.
Endurance exercise
(distance running) involves long periods of moderate activity.
Adaptation to endurance exercise results in?
1) the interconversion of Type IIx (FG) → Type IIa (FOG) fibers
2) mitochondrial biogenesis.
T/F The interconversion of Type II → Type I fibers is rare and requires extensive endurance training.
T
Skeletal muscle adaptations persist as long as?
the functional demand is sustained
