Exam 2- Mason

EXERCISE PHYSIOLOGY EXAM 2 COMPREHENSIVE STUDY GUIDE

Exam Information

  • Exam Date: April 6

  • Chapters Covered: 7–12

CARDIOVASCULAR SYSTEM

Structure and Function of the Heart

  • Description:

    • The heart is a four-chambered muscular pump.

    • Main Chambers:

    • Right Atrium (RA)

    • Right Ventricle (RV)

    • Left Atrium (LA)

    • Left Ventricle (LV)

    • Note: The Left Ventricle (LV) has the thickest wall due to its responsibility for pumping blood to the entire body.

  • Valves and Blood Flow:

    • Valves ensure one-way blood flow:

    • Tricuspid Valve: RA → RV

    • Pulmonary Valve: RV → pulmonary arteries → lungs

    • Mitral (Bicuspid) Valve: LA → LV

    • Aortic Valve: LV → aorta → body

    • Blood Flow Pathway:

    • Body → RA → RV → Lungs → LA → LV → Body

  • Coronary Arteries:

    • Supply oxygenated blood to the myocardium.

Cardiac Cycle

  • Systole:

    • Represents ventricular contraction.

    • Produces systolic blood pressure (SBP).

  • Diastole:

    • Represents ventricular relaxation.

    • Produces diastolic blood pressure (DBP).

Electrical Conduction System

  1. Sinoatrial (SA) Node: Initiates impulse (functions as the pacemaker).

  2. Impulse spreads across the atria, leading to atrial contraction.

  3. Atrioventricular (AV) Node: Delays the signal to ensure proper filling of the ventricles.

  4. Bundle of His: Transmits impulse down the septum of the heart.

  5. Purkinje Fibers: Distribute the signal, leading to ventricular contraction.

Heart Rate Control

  • Sympathetic Nervous System (SNS):

    • Increases heart rate.

  • Parasympathetic Nervous System (PNS) (via the vagus nerve):

    • Decreases heart rate.

  • Influenced by:

    • Hormones (e.g., epinephrine)

    • Temperature

    • Level of physical fitness

Response to Acute Exercise

  • Heart Rate (HR):

    • Increases

  • Stroke Volume (SV):

    • Increases

  • Cardiac Output (Q):

    • Calculated as Q=HR×SVQ = HR × SV, increases significantly with exercise.

  • Blood Flow Redistribution:

    • Blood flow increases to working muscles while decreasing to non-essential organs.

Pressure, Flow, and Resistance

  • Flow (Q):

    • Defined by the equation:
      Q=racextPressuredifference(riangleP)extResistance(R)Q = rac{ ext{Pressure difference} ( riangle P)}{ ext{Resistance} (R)}

    • Effects:

    • Increased pressure increases flow.

    • Increased resistance decreases flow.

    • Vessel diameter: Strongly influences resistance, larger diameters reduce resistance.

Blood Flow Regulation

  • Regulated primarily by arterioles through:

    • Sympathetic Vasoconstriction: Increases resistance.

    • Local Metabolites: Such as CO2, H+, lactate, and adenosine, can induce vasodilation.

    • Nitric Oxide (NO): Promotes vasodilation.

    • Hormonal Control: Influences blood flow dynamics.

Functional Sympatholysis

  • During exercise, local metabolites can override sympathetic vasoconstriction, promoting increased blood flow to active muscles.

Venous Return Mechanisms (Upright Exercise)

  1. Muscle Pump:

    • Skeletal muscle contractions push blood toward the heart.

  2. Respiratory Pump:

    • Pressure changes during breathing aid venous return.

  3. Venoconstriction:

    • Sympathetic activation leads to constriction of veins, enhancing venous return.

Chronic Adaptations to Aerobic Training

  • Resting Heart Rate: Decreased

  • Submaximal Heart Rate: Decreased

  • Stroke Volume: Increased

  • Cardiac Output: Increased

  • Parasympathetic Tone: Increased, which is the primary reason for lower resting HR in trained individuals.

Population Differences

  • Genetic Factors: Account for 25–50% of VO2 max variation among individuals.

  • Sex Differences: Account for approximately 10% of variation.

  • Presence of responders and non-responders to training stimuli.

FUNCTIONS OF BLOOD

  • Transport:

    • Carries oxygen, nutrients, hormones, and waste products.

  • Regulation:

    • Maintains temperature, pH levels, and fluid balance in the body.

  • Protection:

    • Involves immune function and clotting processes.

RESPIRATORY SYSTEM

Structure and Function

  • Function:

    • Delivers oxygen to the alveoli.

    • Facilitates oxygen transfer to the blood.

    • Removes carbon dioxide from the body.

    • Contributes to pH regulation, temperature control, vocalization, and aiding immune defense.

Mechanics of Breathing

  • Inspiration:

    • Diaphragm contracts, thoracic cavity expands, leading to decreased pressure and air flowing into the lungs.

  • Expiration:

    • Diaphragm relaxes, thoracic cavity decreases, leading to increased pressure and air flowing out of the lungs.

Lung Volumes

  • Tidal Volume (VT):

    • Normal breath, approximately 500 mL.

  • Inspiratory Reserve Volume (IRV):

    • Additional volume of air that can be inhaled.

  • Expiratory Reserve Volume (ERV):

    • Additional volume of air that can be exhaled.

  • Residual Volume (RV):

    • Volume of air remaining in the lungs after maximal exhalation.

Lung Capacities

  • Vital Capacity (VC):

    • Calculated as VC=VT+IRV+ERVVC = VT + IRV + ERV.

  • Total Lung Capacity (TLC):

    • Calculated as TLC=VT+IRV+ERV+RVTLC = VT + IRV + ERV + RV.

  • Functional Residual Capacity (FRC):

    • Calculated as FRC=ERV+RVFRC = ERV + RV.

  • Inspiratory Capacity (IC):

    • Calculated as IC=VT+IRVIC = VT + IRV.

Gas Transport

  • Oxygen Transport:

    • Primarily transported bound to hemoglobin.

  • Carbon Dioxide Transport:

    • Mainly transported as bicarbonate (HCO3-).

pH and Bohr Effect

  • Decreased pH:

    • Represents increased acidity, which reduces hemoglobin’s affinity for oxygen.

    • This response enhances the unloading of oxygen to working muscles during exercise.

Afferent Feedback

  • Chemoreceptors:

    • Detect changes in carbon dioxide (CO2), oxygen (O2), and pH levels.

  • Mechanoreceptors:

    • Detect movement and stretch.

  • Baroreceptors:

    • Detect pressure changes within the cardiovascular system.

Respiratory Adaptations to Training

  • Slight Increase:

    • In total lung capacity.

  • Increased VO2 Max:

  • The respiratory system is typically not a limiting factor in performance.

RESISTANCE TRAINING ADAPTATIONS

Definitions

  • Muscular Strength:

    • Maximum force exerted, commonly measured as one-repetition maximum (1RM).

  • Muscular Endurance:

    • Ability to sustain repeated contractions over time.

Timeline of Adaptations

  • Weeks 1–4:

    • Neural adaptations dominate, allowing strength gains without significant hypertrophy.

  • Weeks 4–8:

    • Hypertrophy begins to emerge.

  • Weeks 8–16:

    • Noticeable increases in muscle cross-sectional area occur.

Neural Adaptations

  • Motor Unit Recruitment:

    • Increases with training leading to improved strength.

  • Firing Rate:

    • Increased rate coding contributes to greater force output.

  • Coordination:

    • Much improved, allowing for better performance during resistance exercises.

  • Note: Strength gains may occur even in the absence of hypertrophy.

Hypertrophy

  • Definition:

    • Increase in muscle fiber size.

  • Components:

    • Increased amounts of actin, myosin, and myofibrils within the muscle fibers.

    • Growth in Type II fibers ranges from 20–45% and Type I fibers from 10–25%.

    • Whole muscle growth averages about 10–30% within 3–6 months of consistent training.

Mechanisms of Growth

  • mTOR Signaling Pathway:

    • Plays a crucial role in increasing muscle protein synthesis (MPS).

  • Positive Net Protein Balance:

    • Required for muscle growth to occur.

  • Satellite Cells:

    • Provide additional nuclei to support growth and repair of muscle fibers.

Muscle Architecture

  • Pennation Angle:

    • Increases by approximately 5–20%, which can enhance force production.

  • Fiber Length:

    • Experiences slight increases.

  • Overall Force Production:

    • Enhanced due to the structural changes in muscle architecture.

Connective Tissue and Bone

  • Tendon Stiffness:

    • Increases by 20–30%.

  • Collagen Synthesis:

    • Increased in response to resistance training.

  • Bone Mineral Density:

    • Increased with consistent weight training.

Hormonal Responses

  • Influencing Hormones:

    • Testosterone, growth hormone, and IGF-1 contribute to hypertrophy.

  • Acute and Chronic Hormonal Responses:

    • Both play roles in the training adaptations process.

Detraining Effects

  • Strength Loss:

    • Begins rapidly, losing approximately 3–4% per day initially without training stimulus.

  • Fiber Type Sensitivity:

    • Type I fibers are more adversely affected during periods of detraining.

Sex Differences

  • Strength Gains:

    • Men and women tend to attain strength at comparable relative rates despite physiological differences.

AEROBIC AND ANAEROBIC TRAINING

Central Adaptations (Cardiovascular)

  • Stroke Volume: Increased as a response to training.

  • Cardiac Output: Increased as a result of aerobic training adaptations.

Peripheral Adaptations (Muscle)

  • Mitochondria Density: Increased, enhancing aerobic metabolism.

  • Capillary Density: Increased, improving oxygen delivery to the muscle.

  • Oxygen Extraction: Enhanced capacity to utilize available oxygen.

Aerobic Training Adaptations

  • VO2 Max: Increased with consistent aerobic training.

  • Resting Heart Rate: Decreased, indicative of improved cardiovascular efficiency.

  • Endurance Performance: Improved through adaptations in cardiovascular and muscular systems.

Anaerobic Training Adaptations

  • Muscle Size: Increase due to hypertrophy from resistance training.

  • Glycogen and Creatine Stores: Enhanced, providing better energy substrates for high-intensity efforts.

  • Buffering Capacity: Improved, allowing for greater tolerance to lactate buildup.

  • Type II Fibers: Increased in proportion and size as a result of anaerobic training.

Metabolic Adaptations

  • Efficiency in Energy Production: Improved, enabling efficient ATP production.

  • Lactate Tolerance: Increased capacity to tolerate higher levels of lactic acid during intense exercise.

General Adaptation Framework

  • Cycle of Training:

    • Stress → adaptation → improved performance through training adjustments.

Overtraining Signs

  • Symptoms Include:

    • Chronic fatigue.

    • Decreased performance outputs.

    • Sleep disturbances leading to poor recovery.

    • Mood changes indicative of mental fatigue.

    • Elevated resting heart rate as a physiological response.

PRINCIPLES OF EXERCISE TRAINING

SAID Principle

  • Definition: Specific Adaptations to Imposed Demands, underscoring that training adaptations occur in response to the specific demands of exercise.

Core Principles

  • Individuality:

    • Responses to training vary significantly among individuals.

  • Specificity:

    • Training must be tailored to align with individual goals and objectives.

  • Progressive Overload:

    • Increasing training stimuli over time is essential for continued improvement.

  • Reversibility:

    • Adaptations are lost when training ceases; consistent effort is necessary to maintain gains.

  • Variation (Periodization):

    • Planned alterations in training intensity and volume to optimize performance and recovery.

Training Guidelines

  • Exercise Order:

    • Large muscle groups should be prioritized before small muscle groups.

    • Multi-joint exercises should be performed before single-joint exercises.

    • High-intensity activities should precede low-intensity exercises in training sessions.

Force-Velocity Relationship

  • Relationship Characteristics:

    • High force correlates with low velocity; as the force demand increases, velocity decreases.

    • Conversely, high velocity corresponds with low force; rapid movements typically involve lighter loads.

Free Weights vs Machines

  • Free Weights:

    • Recruit stabilizing muscles providing a more functional strength training stimulus.

    • More beneficial for advanced individuals who have developed competency in movement patterns.

  • Machines:

    • Generally safer and easier to use, making them more suitable for beginners.

    • Allow for targeted isolation of specific muscles.

High-Intensity Interval Training (HIIT)

  • Structure:

    • Typically involves a 2:1 work-to-rest ratio.

  • Benefits:

    • Improves aerobic capacity efficiently with shorter training durations.

EXERCISE FOR HEALTH AND FITNESS

Benefits of Exercise

  • Improved Cardiovascular Health: Enhances heart and vascular function.

  • Improved Cognitive Function: Supports brain health and cognitive capacities.

  • Reduced Risk of Chronic Disease: Diminishes likelihood of developing various chronic health conditions.

  • Maintenance of Brain Structure and Function: Preserves neuroplasticity and cognitive abilities.

Exercise Prescription (6 Factors)

  1. Mode: Type of exercise performed.

  2. Frequency: How often exercise occurs.

  3. Intensity: Level of effort during exercise.

  4. Duration: Length of each exercise session.

  5. Volume: Total amount of exercise performed over time.

  6. Progression: Advancing training stimuli over time for continued adaptation.

ACSM Guidelines

  • Moderate Exercise: Minimum of 30 min on at least 5 days per week.

  • Vigorous Exercise: Minimum of 20 min on at least 3 days per week.

Minimum Threshold

  • Definition: The minimum level of exercise necessary for improvement, which varies by individual attributes and fitness levels.

Health Screening and Risk Stratification

  • Risk Categories:

    • Low Risk: No major risk factors present.

    • Moderate Risk: Two or more risk factors present.

    • High Risk: Presence of known disease or symptoms requiring medical evaluation.

Components of an Exercise Program

  1. Warm-up: Prepares the body for exertion.

  2. Endurance Training: Builds cardiovascular fitness.

  3. Resistance Training: Enhances strength and muscle performance.

  4. Flexibility: Improves range of motion and reduces injury risk.

  5. Cool-down: Assists in recovery post-exercise.

  6. Recreational Activity: Engages in enjoyable physical activities for leisure and health.

Prolonged Sitting

  • Negative Effects:

    • Increases in insulin resistance and adversely affects metabolism.

    • Cannot be fully offset by engaging in exercise alone.

  • NEAT (Non-Exercise Activity Thermogenesis): Helps to reduce health risks associated with sedentary behavior.

Body Composition

  • Importance: Understanding the difference between body fat percentage and BMI is essential for proper health assessment and management of fitness goals.