musculoskeletal adaptations to exercise Flashcards
1
Q
fast twitch fibers exhibit 4 characteristics
A
- high capability for electrochemical transmission of AP
- high myosin ATPase activity
- rapid Ca2+ release and uptake by an efficient sarcoplasmic reticulum
- high rate of crossbridge turnover
- factors contribute to fibers rapid energy generation for quick, powerful muscle actions
- enzymes in higher amount for glycolosis
- phosphocreatine and glycolysis
2
Q
fast twitch (II)
A
- speed of shortening and tension development is 3-5 times faster than slow-twitch
- rely on well-develped short-term glycolytic system for energy transfer
- predominates in anaerobic type activity
- play important role in stop and go or change of pace sports
3
Q
2 type 2 subtypes
A
- IIa: fast-oxidative-glycolytic fibers (get recruited more for aerobic, more likely to change with training)
- IIb: greatest anaerobic potential and most rapid shortening velocity; represents the “true” fast-glycolytic fiber
4
Q
slow twitch
A
-generate energy for ATp resynthesis predominantly through the aerobic system of energy transfer
5
Q
4 distinguishing features of slow twitch
A
- low myosin ATPase activity
- slow calcium handling ability and shortening speed
- less well-developed glycolytic capacity than fast-twitch fibers
- large and numerous mitochondria
- differences come from NERVES
- highly fatigue resistant and ideally suited for prolonged aerobic exercise
- slow-oxidative fibers with slow shortening speed and rely on oxidative metabolism
6
Q
adaptations associated with aerobic training
A
- larger and more numerous mitochondria
- capillary density increases
- increases in oxidative enzymes (CPK, Myokinase, etc)
- no change in muscle strength, however endurance improves at low outputs
- selective hypertrophy
- –muscles specifically doing work
- good at decreasing % body fat, but not good at increasing FFA
7
Q
adaptations associated with resistance training
A
- increase muscle strength/endurance
- increase fiber size and amount Type IIa fibers
- enzyme activity increases (CPK, myokinase, PFK)
- increase metabolic energy stores
- increase connective tissue integrity
- decrease % body fat, increase FFM (lean muscle)
8
Q
protocol for resistance training
A
3 sets, 10-12 reps (12), 30-60 second rest
-minimize rest, maximize rep
s-above 75% 1 rep max
-improves CT too
9
Q
why does muscle hypertrophy
A
- increase in muscular tension with exercise provides the primary stimulus to initiate process of hypertrophy
- muscle fiber growth occurs from repeated muscle injury (particularly with eccentric actions)
10
Q
why eccentric contraction
A
- high levels of strain on muscle fibers disrupt the myofibrils structure
- SR
- T-system
- -both disruptions disrupt calcium transmission
- Z disk
11
Q
muscle fiber response to injury
A
- damage to a single muscle fiber leads to following
- inflammation
- proliferation
- maturation
- change in pH and lactic acid
- 24-48-72 hours following activity=disruption in actual tissue itself
- builds back up better
- repeated breakdown=hypertrophy over time
12
Q
hypertrophy
A
- mRNA mediates stimulation of myofibrillar protein synthesis
- overcompensation of protein synthesis in response to muscle damage
13
Q
muscle fiber type transformation with specific exercise
A
- aerobic exercise at low intensity produces no change in fiber type
- aerobic exercise at high intensities produces a change in type from fast to slow (fast glycolytic-fast oxidative glycolytic)
14
Q
muscle fiber hyperplasia
A
- addition/creation of new fibers
- research is inconclusive and models used to support hyperplasia mostly deal with animals
- CANNOT ADD MUSCLE FIBERS
15
Q
fiber response to de-training
A
- de-training=cessation of resistance exercise
- limited data examining response to detraining
- -will see reductions in muscle strength
- -will see reduction in type II fiber area
- not to be confused with disuse
- takes less time to get back to where you were if well trained athlete
- training, stop training, takes less time to get back
