Lecture 9 : Peripheral Muscle Adaptations to Resistance Training

Question 1

what happens to the fluid and substances in sarcoplasmic hypertrophy

Answer 1

the sarcoplasm within muscle cells expands due to an increase in fluid, glycogen, creatine phosphate and other substances necessary for muscle production and muscle function

Question 2

what happens to muscle volume in sarcoplasmic hypertrophy

Answer 2

as the sarcoplasm expands, the overall volume of the muscle cell increases

can result in visibly larger muscle size

Question 3

what happens to endurance and energy storage in sarcoplasmic hypertrophy and why

Answer 3

associated with improvements in muscle endurance + ability to sustain contraction over extended periods

because increased sarcoplasmic volume allows for greater storage of energy substrates like glycogen and creatine phosphate

Question 4

what is the training method of sarcoplasmic hypertrophy (what are the aim of these techniques also)

Answer 4

often stimulated by higher repetitions, shorter rest periods and moderate to light weights

aim to fatigue muscles while promoting metabolic stress and fluid accumulation

Question 5

how is appearance vs strength affected by sarcoplasmic hypertrophy

Answer 5

sarcoplasmic hypertrophy primarily affects the appearance of muscles making them larger and more pumped

does not directly correlate with significant increases in maximal strength or muscle fibre size

more related to improved endurance and muscular stamina

Question 6

what happens to myofibril size in myofibrillar hypertrophy and why

Answer 6

individual myofibrils within muscle fibres increase in size

occurs primarily through addition of contractile proteins such as actin and myosin

Question 7

what happens to strength gains in myofibrilar hypertrophy and why

Answer 7

closely linked to improvements in muscular strength and power

contractile proteins within muscle cells increase in number and size : muscle becomes more efficient at producing force

Question 8

what is the training method of myofibrilar hypertrophy (what are the aim of these techniques also)

Answer 8

typically stimulated by resistance training involving lower reps and higher weights

emphasize maximal or near maximal loads which place high mechanical tension on muscle fibres - trigger adaptations

Question 9

what muscle fibre type is affected by myofibrilar hypertrophy

Answer 9

can affect bpth fast and slow twich fibres, although fast fibres tend to have greater potential for hypertrophy and strength gains

fast fibres : more explosive high intensity activities

slow twitch : more endurance tasks

Question 10

how does myofibrilar and sarcoplasmic hypertrophy differ in terms of muscle volume and density

Answer 10

sarcoplasmic hypertrophy primarily increases the fluid volume within muscles

myofibrilar hypertrophy contributes to a denser and more structurally robust muscle tissue

Question 11

what happens to muscle density in myofibrilar hypertrophy and what does this mean

Answer 11

creates denser muscle fibres and this enhances their ability to generate force and withstand mechanical stress

Question 12

what is absolute strength and how is it usually measured

Answer 12

refers to the maximum amount of force a person can generate, usually measured in terms of weight lifted during a single repetition of an exercise

e.g someone can bench press 100kg for 1RM

Question 12

what is relative strength and how is it often expressed

Answer 12

takes into account a persons strength relative to their body weight

it is often expressed as a ratio or percentage of their body weight lifted

Question 13

factors that affect muscle size

Answer 13

correct stimulus

nutrition

hormonal stress

Question 14

explain the muscle structure basically

Answer 14

muscles are made of many bundles of fibres : fascicles

within fascicles we have muscle fibres

within muscle fibres we have myofibrils

myofibrils are made up of active contractile components : actin and myosin

Question 15

what is the primary site of hypertrophy

Answer 15

myofibrils

Question 16

how is cross sectional area of a muscle increased because of training

Answer 16

with training the number of myofibrils increases or existing ones become thicker

this increases cross sectional area and force generating capacity

Question 17

what are myofibrils

Answer 17

repeating units of sarcomeres (actin and myosin)

Question 18

in hypertrophy more sarcomeres are added in which way and what does this contribute to

Answer 18

more sarcomeres are added in parallel not in series, contributing to increase fibre diameter and strength

Question 19

what is the sarcoplasm

Answer 19

the cytoplasm of the muscle cell

Question 20

though not primary drivers of hypertrophy, both mitochondria and capillaries can …….

Answer 20

increase in number and volume, especially in type 1 fibres

Question 21

what are satellite cells

Answer 21

muscle stem cells

Question 22

when are satellite cells activated

Answer 22

activated with overload

Question 23

what do satellite cells do

Answer 23

they donate nuclei to growing fibres

Question 24

what does more nuclei mean

Answer 24

more capacity to regulate protein synthesis across a large fibre

Question 25

what are peripheral muscle adaptations

Answer 25

changes in metabolic capacity muscle size ratio of fibre types architecture of the muscle

Question 26

list the 5 theories related to muscle hypertrophy

Answer 26

- mechanical tension - muscle damage - metabolic stress - hormonal - energy

Question 27

sarcoplasmic hypertrophy is .....

Answer 27

making a muscle larger without adding myofibrillar proteins like actin and myosin

Question 28

myofibrillar hypertrophy is ...

Answer 28

increase size of myofibrils, the contractile units of the muscle

Question 29

how does metabolic stress promote sarcoplasmic hypertrophy

Answer 29

stimulates the production of growth factors and hormones that promote sarcoplasmic hypertrophy

Question 30

what is a key difference between strength and hypertrophy

Answer 30

hypertrophy we are focusing on decreasing time between sets, which puts our body under oxidative stress where as strength training we want to give our body more rest

Question 31

three reasons why shorter rests are important for hypertrophy

Answer 31

1. maximise metabolic stress 2. greater time under tension 3. increase muscle fibre recruitment

Question 32

short rests create a build up of what to maximise metabolic stress

Answer 32

- lactate - hydrogen ions (lower pH) - inorganic phosphate

Question 33

in high force training (resistance training) what happens to CSA and sarcomeres

Answer 33

increases muscle cross sectional area by adding sarcomeres in parallel increases the overall force, each sarcomere acts independently

Question 34

in high velocity training (plyometrics) what happens to sarcomeres and shortening velocity

Answer 34

may add sarcomeres in series increase shortening velocity at the expense of force production given that sarcomeres in series pull against each other

Question 35

what is meant by regional hypertrophy

Answer 35

(non uniform muscle growth) the most active compartment of the muscle in any exercise will grow the most

Question 36

what are the characteristics of type 1 muscle fibres

Answer 36

- smaller - less fatiguable - high vascularisation - more energy and nutrients to the muscle - lower contractile velocity - we recruit them first

Question 37

what are the characteristics of type 2 muscle fibres

Answer 37

- less oxidative capacity - larger (bigger cross sectional area) - more force production - fatigue quickly

Question 38

high loads at low speeds will create a shift in what fibre types

Answer 38

shift from IIx and IIx/IIa hybrids to more of a pure IIa phenotype and less shift in pure type 1 fibres

Question 39

high loads loads at high speeds means what for fibre types

Answer 39

less of a loss in IIx and IIx/IIa fibres and concomitant decrease or shirt in type 1 fibres to faster phenotype

Question 40

what is the hypertrophy potential of type 1 fibres

Answer 40

lower than type 2 fibres, but they do hypertrophy, especially under higher volume , lower load training

Question 41

what is the hypertrophy potential of type IIa fibres

Answer 41

very responsive to resistance training, especially moderate to heavy loads (70-80% 1RM)

Question 42

primary function of type 1 fibres

Answer 42

endurance, fatigue resistance

Question 43

primary function of IIa fibres

Answer 43

force and power with some endurance capacity

Question 44

what is the primary function of type IIx fibres

Answer 44

explosive power, low fatigue resistance

Question 45

what is the hypertrophy potential of type IIx fibres (+but)

Answer 45

high, but ... - these fibres tend to shift toward IIa with regular resistance training - so while IIx fibres have high theoretical hypertrophy potential, they often convert to IIa before hypertrophy is fully expressed

Question 46

what is fibre type transition

Answer 46

process by which muscle fibres change their phenotype, meaning their contractile metabolic properties in response to stimuli like resistance training, endurance training or inactivity

Question 47

what fibre type is probably the most transitional

Answer 47

IIa

Question 48

fibre type transition in resistance training

Answer 48

IIx > IIa

Question 49

fibre type transition in endurance training

Answer 49

IIx >IIa > 1 (in extreme long term cases)

Question 50

fibre type transition in detraining or inactivity

Answer 50

type 1 or type IIa > IIx

Question 51

in terms of fibre type transition why might tapering be helpful

Answer 51

type IIx are the hardest to stimulate but when we rest we get them for free

Question 52

why do fibre types go 1 or IIa > IIx in detraining or inactivity (why do they lose their oxidative capacity)

Answer 52

- motor unit decreases = less neural input - decreased mechanical loading = less activation of growth pathways like mTOR - reduced mitochondrial demand = down regulation of oxidative enzymes and capillary density muscles attempt to conserve energy - type IIx fibres are metabolically cheaper to maintain

Question 53

explain the muscle memory effect - why inital strength gains after inactivity can be rapid

Answer 53

a person returning to training after time off may have more type IIx which are - highly responsive to training - more hypertrophic potential than type 1

Question 54

with ageing, what fibres atrophy more than others

Answer 54

type II fibres atrophy more rapidly then type 1

Question 55

changes in size and number of myofibrils may change the angle of what

Answer 55

may change the pennation angle