Muscle Adaptations and General Adaptation Syndrome

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Questions and Answers

What happens to motor cortex activity during high levels of force development?

It increases. (correct)

It fluctuates irregularly.

It remains unchanged.

It decreases significantly.

Maximal strength and power increases in agonist muscles result from which of the following?

Increase in recruitment and synchronization of firing. (correct)

Decreased nerve terminal branching.

Reduced muscle mass.

Limitations in muscle fiber types.

Untrained individuals can voluntarily activate what percentage of muscle tissue?

50%

70% (correct)

90%

100%

What is one possible change at the neuromuscular junction due to anaerobic training?

More irregularly shaped synapses. Signup and view all the answers

How does anaerobic training affect the stretch reflex response?

It enhances the stretch reflex response. Signup and view all the answers

What change occurs in the Golgi Tendon Organ (GTO) threshold due to anaerobic training?

It decreases, resulting in less inhibitory impulses. Signup and view all the answers

Which adaptation is associated with improved muscle performance due to anaerobic training?

Increased muscle elasticity and shorter amortization. Signup and view all the answers

What is a common strength gain percentage range after 3 to 6 months of resistance training?

25 to 100% Signup and view all the answers

Which factor does NOT contribute to the amount of force generated in a single muscle fiber?

Type of nutrition consumed Signup and view all the answers

What is the term for the initial response to training stress according to Selye’s General Adaptation Syndrome?

Alarm Signup and view all the answers

What type of training generally leads to greater adaptations in the neuromuscular system?

High-intensity training Signup and view all the answers

Which of the following factors does NOT directly alter force output in muscle contraction?

Length of muscle fibers before contraction Signup and view all the answers

What is the primary mechanism by which skeletal muscle adapts to anaerobic training?

Increase in size of muscle fibers Signup and view all the answers

Which type of hypertrophy involves an increase in the cross-sectional area of muscle fibers?

Sarcoplasmic Hypertrophy Signup and view all the answers

What is the role of the central nervous system in advanced lifters during power training?

To allow selective recruitment of motor units Signup and view all the answers

Which adaptation is NOT typically a result of anaerobic training?

Decrease in connective tissue strength Signup and view all the answers

What is hyperplasia in the context of muscular adaptations?

Increase in the number of muscle fibers Signup and view all the answers

Which statement accurately describes muscle atrophy?

Decrease in muscle girth Signup and view all the answers

Which of the following adaptations can occur due to anaerobic training?

Changes in muscle substrate content Signup and view all the answers

What type of hypertrophy involves the increase in size of myofibrils?

Myofibrillar Hypertrophy Signup and view all the answers

Which factor may decrease as a result of anaerobic training adaptations?

Mitochondrial density Signup and view all the answers

What directly contributes to the increase in the diameter of a myofibril during hypertrophy?

Addition of new myofilaments to the external layer Signup and view all the answers

What role do satellite cells serve in muscle hypertrophy?

They act as myogenic stem cells for muscle regeneration Signup and view all the answers

How does resistance training affect the angle of pennation in muscles?

It increases the angle of pennation Signup and view all the answers

What primary stimulus leads to the growth of tendons, ligaments, and fascia?

Mechanical forces during exercise Signup and view all the answers

What happens to mitochondrial density as a result of resistance training?

It decreases Signup and view all the answers

What effect does sprint training have on calcium release?

It enhances calcium release Signup and view all the answers

What contributes to the maintenance of an adequate myonuclear domain during muscle hypertrophy?

Increased proliferation of myonuclei from satellite cells Signup and view all the answers

An increase in the number of myofibrils during hypertrophy is primarily caused by?

Splitting of existing myofibrils Signup and view all the answers

What physiological change occurs alongside an increase in sarcoplasmic reticulum during resistance training?

Increased myofibrillar volume Signup and view all the answers

Study Notes

Neuromuscular Adaptations

Resistance training (3-6 months) leads to enhanced force production and maximal movement.
Strength gains range from 25% to 100%.
Neural control changes.
Muscle hypertrophy occurs.
Young males exhibit greater strength gain potential.
Muscle plasticity is higher.

Selye's General Adaptation Syndrome (GAS)

Explains responses to training stress.
Individuals adapt or experience exhaustion depending on training stress levels.
GAS stages: alarm, resistance, adaptation/exhaustion.

General Adaptation Syndrome (GAS) (Detailed)

Alarm phase: Initial training, performance decreases due to fatigue.
Resistance phase: Adaptation; system returns to baseline or surpasses it.
Supercompensation phase: Increased capacity for performance.
Overtraining phase: Excessive stressors lead to performance suppression or overtraining syndrome.

Muscle Damage & Adaptations

Unaccustomed exercise (eccentric muscle actions) cause muscle damage.
High muscle force damages sarcolemma, releasing cytosolic enzymes and myoglobin.
Damaged myofibrils and noncontractile structures lead to metabolite accumulation.
Reduced force capacity.
Delayed-onset muscle soreness results from inflammation.

Glycogen Supercompensation

Glycogen levels increase after exercise and recovery.
Low glycogen levels to normal glycogen increased glycogen levels.
High carbohydrate intake during recovery boosts glycogen stores.

Adaptations to Resistance Training

Key changes with resistance training include altered muscle fiber size and type, strength improvements, increased mitochondria, and shifts toward a faster muscle fiber type.
Neural changes include increases in motor unit recruitment rate and synchronization of firing, as well as activation of the stretch reflex.

Adaptations in Force Gradation

Force generated in a single muscle fiber depends on the number of cross-bridges.
Five key factors affecting force production include: motor unit recruitment, motor unit discharge frequency, motor unit type, stretch reflex activation, and contraction speed.
Neuromuscular adaptations increase force output by changing these factors.

Neural Adaptations

Anaerobic training affects the neuromuscular chain, starting from higher brain centers and influencing individual muscle fiber levels.
Greater adaptations occur with high-intensity training and show up early in the program.
Significant neural adaptations lead to strength improvements.
Motor cortex activity increases with increasing force levels and new exercises/movements.
Maximal strength and power increase due to factors such as motor unit recruitment, firing rate, and synchronization.

Neural Adaptations (Neuromuscular Junction)

Anaerobic training changes the neuromuscular junction (NMJ).
Increased surface area and irregularly shaped synapses.
Increased nerve terminal length and area and dispersed acetylcholine receptors.

Neural Adaptations (Proprioceptors)

Anaerobic training improves stretch reflex response, enhancing force development and muscle spindle/elasticity properties, shortening amortization phase and increasing golgi tendon organ (GTO) threshold and, decreasing inhibitory impulses.

Size Principle Adaptations

Heavy resistance training recruits more muscle fibers in consecutive order based on size (size principle).
In advanced lifters, the nervous system might allow for recruiting motor units out of order.
This allows for greater power and speed production.

Muscular Adaptations

Anaerobic training leads to hypertophy(growth of muscles).
Connective tissue strength, and glycogen levels, increase.
Changes in muscle substrate and glycolytic enzyme activity.
Possible increased mitochondria and capillary density.
Shifts in fiber type.

Muscular Adaptations (Detailed)

Muscle growth (hypertrophy) is primarily due to increased size of existing muscle fibers (not the actual number of fibers)
An increase in muscle strength/power.
Hyperplasia is a rare event and is not a prominent factor in muscle adaptation.

Satellite Cells & Hypertrophy

Satellite cells are myogenic stem cells vital in muscle regeneration.
Acute damage and stretching trigger satellite cell activation and proliferation..
Satellite cells migrate to injured regions, repair damaged myofibers, and become new myonuclei.
This is essential to maintain an adequate myonuclear domain which helps with muscle hypertrophy.

Muscular Adaptations (Structural & Architectural Changes)

Resistance training increases myofibrillar volume, sarcoplasmic density, and sarcoplasmic reticulum and T-tubule density.
Sodium-potassium ATPase activity increases.
Sprint training enhances calcium release.
Resistance training has an impact on the angle of pennation.

Other Muscular Adaptations

Reduced mitochondrial density.
Reduced capillary density.
Enhanced buffering capacity (acid-base balance).
Muscle substrate and enzyme activity changes.

Connective Tissue Adaptations (Tendons, Ligaments, and Fascia)

Mechanical forces (exercise) drive connective tissue adaptation.
Consistent anaerobic exercise modifies the threshold for connective tissue changes.
Fibroblasts build connective tissue, primarily collagen.
Type I collagen is found in bone, tendons, and ligaments.
Types of collagen fibers have similar arrangements to muscle fibers.

Connective Tissue Adaptations (Detailed)

Tendon changes include increased collagen fibril diameter, more covalent cross-links, an increase in the collagen fibrils, and increased collagen fibril density.
High load-bearing regions of tissue, including junctions between tendons/ligaments and bone, and the fascia network of skeletal muscle, are impacted by strength.

Connective Tissue Adaptations (Bone)

Trabecular bone adapts quickly to stimuli, compared to cortical bone, which takes longer.
The minimal essential strain (MES) threshold is the minimum force needed for new bone formation.
MES is about one-tenth the force needed to fracture a bone.
Muscle strength and hypertrophy increase bone load and can lead to increased bone density.

Bone Remodeling

Weight-bearing forces cause bending, stimulating new bone formation where bending is greatest.
Osteoblasts actively build new collagen fibers along the bone's periosteum.
Osteoblasts migrate to deformed areas.
Collagen fibers mineralize, enhancing bone diameter.

Why Specific Adaptations Occur

The type of stress (overload) triggers specific adaptive responses.
High load resistance training prioritizes mechanical stress responses.
High volume/short rest prioritizes metabolic stress and damage responses.

Review Questions

Explanation of GAS.
Significance of neural adaptations to strength changes.
Impact of reps and load on resistance training adaptations.
Seven explained neural adaptations.
Muscular adaptations to anaerobic training.
Understanding the underlying reasons for muscle fiber hypertrophy.

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Description

Explore the intricacies of neuromuscular adaptations due to resistance training, including strength gains and neural control changes. Understand Selye's General Adaptation Syndrome, its stages, and how individuals adapt to training stress. This quiz delves into muscle damage and the phases of adaptation, including alarm and overtraining.