Chapter 5: Adaptations to Anaerobic Training Programs Flashcards
Anaerobic Training
- Characterized by high-intensity, intermittent bouts of exercise
- Requires ATP to be regenerated at a faster rate than the aerobic system is capable of
- Works in the absence of oxygen
Divisions of the Anaerobic Training System
- Anaerobic alactic system
- Anaerobic lactic system
Anaerobic Alactic System
AKA phosphagen or creatine phosphate system
Anaerobic Lactic System
AKA glycolytic system
Types of adaptations to anaerobic training
- Central nervous system adaptations
- Motor unit adaptations
- Neuromuscular junction adaptations
- Neuromuscular reflex potentiation adaptations
Central Adaptations to Anaerobic Training
- Substantial changes in the spinal cord, particularly along the descending corticospinal tracts
- Recruitment of fast-twitch motor units is elevated
Motor Unit
- The functional unit of the neuromuscular system
- Consists of the alpha motor neuron and the muscle fibers it activates
- May innervate <10 fibers, up to >100 fibers
Size Principle
Motor units are recruited in an ascending order according to their recruitment thresholds and firing rates
Selective Recruitment
Under certain circumstances, an athlete is able to inhibit the lower-threshold motor units in favor of activating higher-threshold motor units
Motor Unit Adaptations
- As muscle size increases it does not require as much neural activation to lift a given load
- Increased rate and sequence of firing
Neuromuscular Junction
The interface between the nerve and the skeletal muscle fibers
Adaptations of the NMJ
- Increases in size
- Greater dispersion of acertlcholine receptors within the end-plate region
Anaerobic Training and the Myotatic Reflex
- Anaerobic training improves the reflex response of the neuromuscular system and enhances the magnitude and rate of force development via this reflex
Electromyography (EMG)
A common research tool used to examine the magnitude of neural activation within skeletal muscle
Types of EMG
- Surface
- Intramuscular (needle or fine wire)
Surface EMG
- Requires placement of adhesive electrodes on the surface of the skin where they are able to monitor a large area of underlying muscle
- Most effective for monitoring superficial muscle
- More body fat = weaker signal
Intramuscular EMG
- A needle electrode, or a needle containing two fine-wire electrodes, is inserted through the skin and positioned into the belly of the muscle itself
- Places emphasis on specificity of assessment
Cross-Education
Exercising muscle undergoing unilateral resistance training produces increased strength and neural activity in the contralateral resting muscle
Bilateral Deficit
- Evident in untrained individuals
- Force produced when both limbs contract together is lower than the sum of the forces they produce when contracting unilaterally
Bilateral Facilitation
An increase in voluntary activation of the agonist muscle groups occurs
What do EMG studies show about antagonist activation after anaerobic training?
- Normally, cocontraction of antagonist muscles occurs to serve as a protective mechanism to increase joint stability and reduce risk of injury
- Too much antagonist activity restricts max force production in the agonist
- Anaerobic training reduces antagonist cocontraction, allowing the agonist to improve force production
Muscular Adaptations to Anaerobic Training
- Muscular growth
- Fiber size changes
- Fiber type transitions
- Structural and architectural changes
Hypertrophy
- The enlargement of muscle fiber cross-section area (CSA) following training
- There’s a positive relationship between hypertrophy and strength
What happens to the structure in muscle as a result of hypertrophy?
- Net accretion of actin, myosin, myofibrils, titin, and nebulin
- Increases in these components leads to a larger muscle size
Hyperplasia
An increase in the number of muscle fibers via longitudinal fiber splitting in response to high-intensity resistance training
Continuum of fiber types (least oxidative to most oxidative)
IIx –> IIax –> IIa –> IIac –> IIc –> Ic –> I
What fiber type transitions are possible as a result of training?
Changes in subtypes are possible, but the proportions for the fiber types are genetically determined
What changes occur to type IIx fibers?
Type IIx fibers represent a “reservoir” that change into amore oxidative form along the continuum as a result of training
How does pennation adapt to resistance training?
Pennation angle increases, allowing for greater CSA, leading to greater force production
Other muscular adaptations
- Decreased mitochondrial density
- Decreased capillary density
- Substantial reductions in muscle and blood pH
Examples of connective tissue
- Bone
- Tendons
- Ligaments
- Fascia
- Cartilage
Types of bone
- Trabecular (spongy)
- Cortical (compact)
- Cortical bone is dense and forms a compact outer shell surrounding the trabecular bone
What happens to bone as a result of resistance training
- Osteoblasts migrate to the bone surface and begin bone modeling
- Osteoblasts manufacture and secrete proteins (collagen molecules) that are deposited in the spaces between bone cells to increase strength
- These proteins form the bone matrix and eventually become mineralized as hydroxyapatite
Hydroxyapatite
Calcium phosphate crystals
Where does new bone formation occur?
The outer surface of the bone (periosteum), increasing diameter and strength
Minimal Essential Strain (MES)
- The threshold stimulus that initiates new bone formation
- Thought to be 1/10 of the force required to fracture bone
Bone Mineral Density (BMD)
The quantity of mineral deposited in a given area of the bone
How long does bone take to adapt to training?
6 months or longer
Principles of training to increase bone strength
- Specificity of loading
- Speed and direction of loading
- Sufficient volume
- Appropriate exercise selection
- Progressive overload
- Variation
Specificity of Loading
- Demands the use of exercises that directly load the particular region of interest of the skeleton
- This is because if the body interprets a force as new or novel, they will stimulate bone growth in the area that is receiving the strain
Osteoporosis
A disease in which BMD and bone mass become reduced to critically low levels
Osteogenic Stimuli
- Factors that stimulate new bone formation
Structural Exercises
Exercises which direct the force vectors primarily through the spine and hip
Exercises meant to stimulate bone growth should:
- Involve multiple
- Direct the force vectors primarily through the spine and hip
- Apply external loads heaver than those with single-joint assistance exercises
Progressive Overload
Progressively placing greater than normal demands on the exercising musculature
Stress Fracture
Microfractures in bone due to structural fatigue
Training variation and bone growth
Changing the distribution and direction of the force vectors by using a variety of exercises continually provides a unique stimulus for new bone formation
Collagen Fiber
- The primary structural component of all connective tissue
- Type I for bone, tendon, and ligaments
- Type II for cartilage
Procollagen
- The parent protein of collagen
- Synthesized and secreted by fibroblasts
- Consists of three protein strands twisted around each other in a triple helix
Microfibril
The parallel arrangement of filaments in collagen
Sites where connective tissues can increase strength and load-bearing capacity
- The junctions between the tendon/ligament and bone surface
- Within the body of the tendon/ligament
- In the network of fascia within skeletal muscle
Specific changes within a tendon that contribute to its increase in size and strength
- An increase in collagen fibril diameter
- A greater number of covalent cross-links within the hypertrophied fiber
- An increase in the number of collagen fibrils
- An increase in the packing density of collagen fibrils
Tendon Stiffness
- Force transmission per unit of strain, or tendon elongation
- Increases as a result of resistance training
Main functions of cartilage
- Provide a smooth joint articulating surface
- Act as a shock absorber for forces directed through the joint
- Aid in the attachment of connective tissue to the skeleton
Types of cartilage
- Hyaline
- Fibrous
Hyaline Cartilage
Articular cartilage
Fibrous Cartilage
A tough form of cartilage found in the intervertebral disks of the spine and at the junctions where tendons attach to bone
Endocrine responses to anaerobic training
- Acute changes during and after exercise
- Chronic changes in the acute response to a workout
- Chronic changes in resting concentrations
- Changes in hormone receptor content
Acute changes during and after exercise
- Elevated concentrations of testosterone, molecular variants of growth hormone, and cortisol for up to 30 minutes in men
- Changes occur quickly and then rapidly stabilize
Chronic changes in the acute response to a workout
Any chronic adaptations in acute hormonal response patterns potentially augment the ability to better tolerate and sustain prolonged high exercise intensities
Chronic changes in resting concentrations
- Chronic changes in resting hormone concentrations are unlikely
- Resting concentrations likely reflect the current state of the muscle tissue in response to substantial changes to the training program and nutritional factors
Changes in hormone receptor content
- Resistance training upregulates androgen receptors within 48-72 hours after the workout
Acute cardiovascular responses to anaerobic exercise
- HR, stroke volume, cardiac output, and BP all increase significantly during resistance exercise
Factors affecting increased blood flow in anaerobic training
- Intensity of the resistance
- Duration of the effort
- Size of the muscle mass activated
Reactive Hyperemia
- Muscular contractions greater than 20% of maximal voluntary contraction impedes peripheral blood flow during a set
- Blood flow increases during the subsequent rest period
Chronic cardiovascular adaptations at rest
- Heavy resistance training does little to enhance resting cardiac function
- Greater improvements may occur with a high-volume program with short rest periods
Changes in cardiac dimensions from chronic resistance training
- Absolute left ventricular wall thickness and mass increases
- Little or no change in left ventricular chamber size or volume
- Higher absolute posterior left ventricular and intraventricular septum wall thickness
Chronic adaptations of the acute cardiovascular response to anaerobic exercise
Chronic training reduces the cardiovascular response to an acute bout at a given workload
Ventilatory response to anaerobic exercise
- Ventilation rate is either unaffected or only moderately improved by anaerobic training
- Increased tidal volume and breathing frequency with maximal exercise
- Improves ventilation efficiency (reduced ventilatory equivalent)
What affect does resistance training have on aerobic training?
- Heavy resistance training has limited, if any, negative effects on aerobic power
- Power development appears to be negatively affected more than strength during concurrent training
Overtraining
Accumulation of training stress can result in long-term decrements in performance with or without associated physiological or psychological signs and symptoms of maladaptation
Overreaching
- AKA functional overreaching (FOR)
- Excessive training that leads to short-term decrements in performance
Nonfunctional Overreaching (NFOR)
Intensification of a training stimulus continues without adequate recovery and regeneration
Overtraining Syndrome (OTS)
- Prolonged maladaptation of not only the athlete, but also of several biological neurochemical, and hormonal regulation mechanisms
- Inability to sustain high-intensity exercise
Types of OTS
- Sympathetic overtraining syndrome
- Parasympathetic overtraining syndrome
Sympathetic Overtraining Syndrome
- Increased sympathetic activity at rest
- Thought to develop before the parasympathetic syndrome
- Predominates in younger athletes training for speed or power
Parasympathetic Overtraining Syndrome
- Increased parasympathetic activity at rest and with exercise
- Eventually all states of overtraining culminate in the parasympathetic syndrome and the chronic suppression of most physiological systems
Detraining
A decrement in performance and loss of the accumulated physiological adaptations following the cessation or reduction of anaerobic training
How long does it take for detraining to occur
Strength can be maintained for ~4-6 weeks
