Chapter 5 Flashcards
Physiological Adaptations to Resistance Training
Increased: Strength, Power Output, Anaerobic Power, Vertical Jump, Speed, Fibre Size, ATP Stores, CP Stores, Glycogen Stores, Fat Free Mass
Decreased: Capillary density, mitochondria density, body fat
Central adaptations
The motor cortex activity will increase when force levels increase and also when we learn new movements.
Corticospinal Tract
Motor Unit adaptations
Max power and strength will increase in agonist muscles due to an increase in their recruitment, synchronization, and firing rate, or a combination of these.
During Resistance training, the muscle fibers become larger due to them being recruited based on their size. They are recruited consecutively in order. Advanced athletes may recruit in different orders due to adaptations.
The Size Principle
Lower threshold units first recruited, lower capacity to produce force than higher ones
Exception for explosive ballistic based contractions
Neuromuscular Junction
Increase Area
Synapses more dispersed and shaped more irregularly
End plate perimeter length/area increase
Acetylcholine receptors are dispersed greater
Neuromuscular Reflex Potentiation
Anaerobic training enhances this reflex. The magnitude and the rate of force development go up.
Anaerobic Training and Electromyography Studies
Increasing EMGs show greater neural activation.
Some studies have strength and power increases showing as much as 73%
Cross Education
Bilateral Deficits in untrained
An increase in the voluntary activation of the agonistic muscles occurs in Bilateral facilitation in trained or stronger people.
Muscle activity changes occur in the antagonist muscles during agonist movements.
Muscular Adaptations
The main adaptations that occur in skeletal muscle are: Increased size, fiber type transitions, enhanced biochemical components. These changes give us more strength, power and endurance.
Muscular Growth
Muscular hypertrophy is referring to enlargement of muscles due to increases in the cross-sectional areas.
Hyperplasia is an increase in muscle fiber numbers due to longitudinal splitting of the fibers.
Hypertrophy results from increases in myosin and actin in the myofibrils and increases in the myofibrils contained in muscle fibers.
Fiber Size Changes
Resistance training shows an increase occurs in both muscle fiber types.
Type I and II fiber area increases.
There are always greater increases with the Type II fibers.
Fiber Type Transitions
The continuum of fiber types is: I, Ic, IIc, IIac, IIa, IIax, IIx.
Structural and Architectural Changes
Myofibrillar volume, sarcoplasmic reticulum density, sodium potassium ATPase activity, T-tubule density, and Cytoplasmic density all increase with resistance training.
Calcium release is enhanced with sprint training.
The angle of pennation increases with resistance training.
Other Muscular Adaptations
Mitochondrial density decreases.
Muscle substrate content and enzyme activities change.
Capillary density decreases.
The buffering capacity increases.
Bone Modeling
This creates stimulus for the bone to form new bone where it is experiencing this deformation.
Osteoblasts lay down additional collagen.
The osteoblasts that were dormant move to this area that is being strained.
Bone diameter increases as the collagen fibers become mineralized.
General Bone Physiology
Trabecular bones respond much quicker to stimuli than cortical bones.
The minimal essential strain is the threshold stimulus used to initiate the formation of new bone.
MES is about one tenth of the force needed to fracture a bone.
If a force reaches this one tenth, or passes it, it will initiate new bone formation.
Principle of Training in order to Increase Bone Strength
The magnitude of the load
The volume of loading
The direction of the force on the bone
The speed of the loading
How Can Athletes Stimulate the Formation of Bone?
They can use exercise that will directly load regions of the skeleton.
Structural exercises can direct force vectors through the spine and hip and this will allow using greater loads while training.
You can overload the musculoskeletal system and then increase load as you become accustomed to it.
Varying exercise selection in order to distribute force vectors which will present a continually unique stimulus.
The Adaptations of Tendons, Ligaments, and Fascia to Anaerobic Training
Collagen fiber diameter increases.
More covalent cross links in a hypertrophied fiber.
Number of collagen fibrils increase.
The packing density of collagen fibrils increases.
How can athletes stimulate adaptations to tendons, ligaments, and fascia?
Long term adaptations come from progressive high intensity loading patterns with external resistance.
High intensity loads are needed because moderate intensities do not change connective tissues.
Forces need to be exerted through a full range of motion.
Cartilage Adaptations to Anaerobic Training
Providing a smooth joint articulating surface
Acting as an absorber of shock for forces through a joint.
Aiding in attaching connective tissues to the skeleton.
Cartilage does not have its own blood supple, so it must get nutrients from diffusion.
Joint mobility is linked with joint health
Moderate intensity anaerobic exercise is good enough to improve thickness of cartilage.
Acute Hormonal Responses
The acute anabolic hormonal responses to anaerobic exercise is important for performance and adaptation in training.
Upregulation of hormone receptors is vital for mediating effects of hormones.
Chronic Changes in Acute Hormonal Response
Doing resistance training consistently improves the acute hormone Reponses to aerobic workouts.
Concentration Change Not Likely
Upregulates androgen receptor content 48-72 hours following workouts
Anaerobic Exercise and the Acute Cardiovascular Responses
This results in an increased stroke volume, oxygen uptake, cardiac output, heart rate, systolic BP, and blood flow to working muscles.
Chronic Cardiovascular Adaptations when at Rest
the resting BP and HR.
Cardiac dimensions are altered by resistance training.
Reduced response to exercise
