Resistance Training Adaptations Flashcards
What does muscular hypertrophy refer to?
⬆️ in size of individual muscle fibres
- Occurs in parallel however some exercise can cause it to happen in series.
MUSCULAR HYPERTROPHY
What is the result when we have more sarcomeres in parallel?
We ⬆️ the amount of force that can be produced.
What does muscular hyperplasia refer to?
⬆️ in the no. of muscle fibres
What is the difference between type 1 and type 2 hypertrophy?
1 = All about ⬇️ degredation
2 = All about ⬆️ synthesis
Where are satellite cells located in the muscle?
Below the sarcolemma ready for action
Brief description of how hypertrophy occurs
Satellite cells activate + migrate to the site.
Duplicate + replicate
Myoblasts –> myotubes.
Reasons why hypertrophy occurs
Mechanical tension
Metabolic stress
Muscle damage
Define mechanotransduction
(Comes under mechanical tension being a reason for hypertrophy to occur)
Ability to sense the muscle undergoing stress.
Sense this stretch w/in the extracellular matrix proteins by a transmembrane protein called integrins.
What happens when integrins are activated?
They cause a cascade of intracellular signalling in muscle fibre cytoplasm to bring about myofibrillogenesis (creation of more myofibrils)
HYPERTROPHY
Difference in force produced by sarcomeres in parallel and sarcomeres in series
Parallel = Doubled
Series = No change
HYPERTROPHY
Difference in velocity by sarcomeres in parallel and sarcomeres in series
Parallel = No change
Series = Doubled
HYPERTROPHY
Difference in shortening capacity produced by sarcomeres in parallel and sarcomeres in series
Parallel = No change
Series = Doubled
Define myogenesis
Replacement of old/damaged muscle fibres in tissue remodelling.
Critical to normal muscle function
What happens overall in myogenesis
Myoblasts fuse to form myotubules which mature into new fibres
WHY DOES HYPERTROPHY OCCUR? - Metabolic stress
What comes under metabolic stress?
Lactate accumulation
H+ (⬆️ acid)
⬆️ inorganic P
Muscle ischemia
Free radical prod
Glycolysis
Why does metabolic stress lead to hypertrophy?
Because it causes things like:
⬆️ fibre recruitment
Elevated hormone levels
Altered myokine prod
Cellular swelling
What is an inhibitor of myogenesis?
Myostatin
If myostatin inhibits myogenesis, and in a study with rats the removal of this inhibitor causing increased hypertrophy, why wouldn’t we want this for humans in aiding muscular hypertrophy?
Actually results in ⬇️ in force prod due to loss of oxidative capacity of the muscle
WHY DOES HYPERTROPHY OCCUR? - Muscle damage
Can lead to a prod in ILGF-1, FGF, IL-5 and IL-6
== These add to an ⬆️ satellite cell proliferation + division = hypertrophy.
What else can hyperplasia be known as?
Longitudinal splitting or lateral budding
Up to how much can resistance training increase the angle of pennation in pennate muscles?
2-5 degrees
How does resistance training increase the angle of pennation?
Due to hypertrophy causing ⬆️ in cross-sectional area of those fibres = thickening fibres causes the angle change.
What can extreme hypertrophy lead to?
Limited force production
What is increased bone strength a result of?
⬆️ deposition of mineral salts
⬆️ prod of collagen fibres
Both types of bone respond equally to adaptations from training but which one responds quicker?
Trabecular
List the factors for bone remodelling
Weight bearing
Magnitude, rate + volume of loading
Direction of forces
Pull of tendon on bones
Wolfs Law
Bone grows or remodels in response to the forces or demands placed upon it
List the stimuli that bring about change in the bone
Bending
Tension (causing narrowing + lengthening of bone)
Compression (causing shortening + widening of bone)
Shear + torsion forces (causing angular distortion)
Difference between stress + strain on the bone
Stress = Level of force on tissue
Strain = Magnitude of deformation in proportion to stress applied
What are the types of strain for the bone?
Linear
Shear
Linear strain in bone
Stresses that can change the tissue length
Shear strain in the bone
Bending of tissue
What amount of force is required for a minimal essential strain?
10% of the forces required to cause a fracture
What is bone fluid flow sensed by?
Mechanosensitive osteocytes
Collagen
A triple-helical protein forming fibrils of great tensile strength.
A major component of the extracellular matrix + connective tissues.
What do the collagen subtypes differ in?
Their tissue distribution
Extracellular components
Cell-surface proteins w/ which they associate
What are the main collagen types?
Type 1
Type 2
Type 5
Where is the type 1 collagen type found?
Muscle
Tendons
Skin
Bone
Where is the type 2 collagen type found?
Cartilage
Where is the type 5 collagen type found?
Cell surface
Hair
What is connective tissue composed of?
H20
Fibroblasts
Fibrocytes
Elastin
Collagen
Ground substances
Collagen adaptations to resistance training
⬆️ in fibril diameter
⬆️ no of fibrils
⬆️ density therefore ⬆️ stiffness
What is the benefit athletes can get from an increased tendon stiffness i.e from the adaptations of collagen from resistance training?
⬆️ GRF (Newtons 3rd law)
= It’s how we use those GRFs that will improve the efficiency + ability to perform tasks.
NEURAL ADAPTATIONS
What improvement is seen in NM reflex potentiation from resistance training?
Enhanced reflex response from muscle spindles
= 20-50% improvement that enhances the magnitude of the force + rate of force development.
NEURAL ADAPTATIONS
What could increased EMG signals be as a result of?
Changes in
Motor unit firing freq
Motor unit recruitment
Motor unit synchronisation
Define rate of force development (RFD)
Change in force over time
Training guidelines for neural adaptions for resistance training
High loads
Fast velocity
Explosive movements
Define PAP (post activation potentiation)
⬆️ in muscle twitch + low-frequency tetanic force after a “conditioning” contractile activity.