🧬 The Protein Synthesis Cycle
Muscle Protein Synthesis (MPS) = the process of building new muscle proteins
Muscle Protein Breakdown (MPB) = the process of breaking them down
* Net muscle gain happens when:
MPS > MPB
🔁 The Full Cycle
1. Stimulus (Training)
Resistance training creates:
• Mechanical tension
• Microdamage
• Metabolic stress
This triggers signaling pathways
2. Signal Activation
Your body “turns on” growth pathways:
• mTOR (primary growth switch)
• Satellite cell activation
• Hormonal responses
3. Amino Acid Availability
You need:
• Essential amino acids (especially leucine)
• Adequate total protein intake
Without this → no building material
4. Protein Synthesis (MPS Spike)
• Muscle cells begin building new proteins
• Peaks ~3–5 hours post-workout
• Elevated up to ~24–48 hours (longer in beginners)
5. Remodeling & Adaptation
• Damaged fibers repaired
• Fibers become thicker & stronger
📈 The “Muscle Full” Effect
MPS doesn’t stay elevated forever:
• After protein intake, MPS rises
• Then plateaus even if amino acids are still present
* This is why meal timing matters
🍗 Protein Timing Strategy
Optimal Pattern:
• 3–5 protein feedings/day
• ~20–40g high-quality protein per meal
Every feeding = new MPS spike
🧪 Key Pathways Involved
mTOR Pathway (Master Growth Switch)
mTOR = mechanistic target of rapamycin
Activated by:
• Resistance training
• Leucine (amino acid)
• Insulin
Role:
• Turns on protein synthesis machinery
• Increases ribosome activity
* This is the #1 driver of hypertrophy
AMPK Pathway (Energy Sensor)
Activated by:
• Low energy (fasting, intense cardio)
Role:
• Conserves energy
• Can inhibit mTOR
* Too much endurance training without fueling = reduced muscle growth
Satellite Cells
• Muscle stem cells
• Activated by damage & tension
• Donate nuclei to muscle fibers
* More nuclei = greater growth capacity
IGF-1 Pathway
Insulin-like Growth Factor 1
• Released locally in muscle after training
• Activates mTOR
• Promotes repair & growth
Myostatin (Growth Inhibitor)
• Limits muscle growth
• Higher levels = harder to build muscle
*Training can suppress myostatin
PROTEIN SYNTHESIS
Hypertrophy = an increase in the size of muscle fibers, not the number of fibers.
At the cellular level, you’re:
• Increasing contractile proteins (actin & myosin)
• Expanding fluid + glycogen storage
• Strengthening structural components of the muscle
🔬 Types of Hypertrophy
1. Myofibrillar Hypertrophy (Strength-focused)
• Growth of contractile fibers
• Increases density + strength
• Lower reps, heavier weight (3–6 reps)
*Harder, denser muscles
2. Sarcoplasmic Hypertrophy (Size-focused)
• Increase in sarcoplasm (fluid, glycogen, enzymes)
• More muscle volume, less direct strength gain
Higher reps (8–15+), more volume
*Bigger-looking muscles (bodybuilder style)
⚙️ The 3 Primary Drivers of Hypertrophy
1. Mechanical Tension (MOST IMPORTANT)
Heavy resistance creates force across muscle fibers.
• Progressive overload is key
• Full range of motion matters
• Controlled reps > sloppy reps
2. Metabolic Stress
That burning feeling = accumulation of:
• Lactate
• Hydrogen ions
• Metabolites
Triggers:
• Cell swelling
• Hormonal signaling
• Fiber recruitment
3. Muscle Damage
Micro-tears from training (especially:
• Eccentric/lengthening phase)
Body repairs - builds back bigger & stronger
🧬 What Actually Happens
1. You train → create tension + stress
2. Muscle fibers experience microtrauma
3. Body activates satellite cells (muscle stem cells)
4. Protein synthesis increases
5. Muscle rebuilds thicker than before
📈 Progressive Overload (Non-Negotiable)
To grow, you must gradually increase:
• Weight
• Reps
• Sets
• Time under tension
• Training density
No overload = no growth
🍗 Protein & Nutrition
Muscle growth depends heavily on protein synthesis:
• Target: ~0.7–1g protein per lb bodyweight
• Caloric surplus (for optimal growth)
• Carbs = fuel + glycogen storage
• Fats = hormone support
🧪 Key Biological Pathways
mTOR Pathway
• Master regulator of muscle growth
• Activated by:
• Resistance training
• Protein (especially leucine)
Satellite Cells
• Donate nuclei to muscle fibers
• Allow greater growth capacity
🏋️ Optimal Training Variables for Hypertrophy
Volume
• 10–20 sets per muscle group per week
Intensity
• 65–85% of 1RM
Reps
• 6–15 (sweet spot)
Rest
• 30 sec – 2 min (shorter = more metabolic stress)
Frequency
• Train each muscle 2x/week
🧠 Fiber Types & Growth
Type I (Slow-twitch)
• Endurance-focused
• Harder to grow
Type II (Fast-twitch)
• Explosive, high growth potential
• Primary target for hypertrophy
Common Mistakes
• Training too light without effort
• Not going close to failure
• Inconsistent progression
• Undereating protein/calories
• Poor sleep
• Program hopping
🧩 Advanced Concepts
Time Under Tension (TUT)
• Slower reps = more stimulus
Mind-Muscle Connection
• Improves activation of target muscles
Training to Failure
• Useful, but don’t overdo it (fatigue management matters)
Deloading
• Periodic recovery weeks to avoid burnout
BUILDING MUSCLE
🏋️ Building Strength & Power
These are related, but not the same:
• Strength = how much force you can produce
• Power = how fast you can produce that force
Power = Force × Velocity
So:
• Heavy slow lifts → build strength
• Fast explosive movements → build power
🧠 Neural vs Muscle Adaptations
Hypertrophy = muscle size
Strength & power = heavily nervous system driven
You’re training your brain + nerves to:
• Recruit more muscle fibers
• Fire them faster
• Coordinate movement more efficiently
🧬 Strength: What’s Actually Improving?
1. Motor Unit Recruitment
• Activating more muscle fibers at once
2. Rate Coding
• Firing signals faster → stronger contractions
3. Coordination
• Better technique = more force output
🏋️ Strength Training Principles
Heavy Loads
• 80–95% of 1RM
Low Reps
• 1–6 reps per set
Longer Rest
• 2–5 minutes
Compound Movements
• Squat
• Deadlift
• Bench press
• Overhead press
• Pull-ups / rows
⚡ Power Training Principles
Speed First
• Move weight as fast as possible
Moderate Loads
• 30–70% of 1RM (or bodyweight)
Explosive Intent
Even with heavier lifts, intent to move fast matters
💥 Best Power Exercises
Olympic Lifts
• Clean
• Snatch
• Push press
Plyometrics
• Box jumps
• Broad jumps
• Depth jumps
Ballistic Movements
• Medicine ball throws
• Kettlebell swings
Sprinting
• One of the purest forms of power output
🧱 Strength vs Power Training Example
Strength Day
• Squat: 5×3 (heavy)
• Deadlift: 4×3
• Bench: 5×5
• Rest: long
Power Day
• Box jumps: 5×3
• Power cleans: 5×2
• Medicine ball throws: 4×5
• Sprint intervals
🔁 Rate of Force Development (RFD)
This is what separates elite athletes:
• Not just producing force
• But producing it quickly
Critical for:
• Sports
• Fighting
• Sprinting
• Jumping
⚙️ Progressive Overload for Strength
Different than hypertrophy:
• Increase weight (primary)
• Improve bar speed
• Refine technique
• Increase neural efficiency
🧠 Technique
Strength is skill-dependent.
Better technique =
• More efficient force transfer
• Less energy leak
• Lower injury risk
💤 Recovery Demands
Strength & power training are CNS intensive
• Longer recovery needed
• Avoid constant maxing out
• Sleep is critical
⚠️ Common Mistakes
• Training like a bodybuilder (too much volume, not enough intensity)
• Not resting enough between sets
• Ignoring explosive work
• Poor form under heavy load
• Going to failure too often (kills performance)
🧩 Advanced Methods
Contrast Training
• Heavy lift → explosive movement
Example:
• Squat → box jump
Cluster Sets
• Short rest within a set to maintain power output
Accommodating Resistance
• Bands / chains to match strength curve
STRENGTH & POWER
Hormones regulate energy availability, tissue adaptation, and emotional well being
They operate through:
• Bloodstream signaling
• Receptor binding
• Feedback loops (especially from the brain)
* Most are controlled through the hypothalamus → pituitary → target gland axis
💪 ANABOLIC (BUILDING & ADAPTATION) HORMONES
Testosterone
• Binds to androgen receptors in muscle cells
• Increases protein synthesis
• Enhances neuromuscular efficiency
Effects
• Muscle growth
• Strength
• Bone density
• Red blood cell production
Low Levels
• Fatigue
• Reduced strength
• Increased fat mass
Interactions
• Suppressed by high cortisol
• Supported by adequate cholesterol & sleep
Growth Hormone (GH)
• Released in pulses (especially deep sleep)
• Stimulates liver to produce IGF-1
Effects
• Tissue repair
• Fat mobilization
• Collagen synthesis
* GH is more about recovery + fat metabolism than direct muscle growth
IGF-1 (Insulin-Like Growth Factor-1)
• Produced mainly in liver (triggered by GH)
• Acts locally in muscle tissue
Effects
• Muscle cell growth (hypertrophy)
• Cell proliferation
Interaction
• Bridges GH → actual tissue growth
Insulin (Anabolic + Metabolic)
• Binds to insulin receptors → opens glucose transporters (GLUT4)
Effects
• Drives glucose into muscle
• Promotes glycogen storage
• Inhibits muscle breakdown
Dysfunction
• Insulin resistance → fat gain, low energy
* Insulin is essential for recovery, not just fat storage
⚡ METABOLIC (ENERGY CONTROL) HORMONES
Thyroid Hormones (T3 & T4)
• Increase mitochondrial activity
• Regulate metabolic rate at cellular level
Effects
• Energy production
• Heat generation
• Fat oxidation
Low Function
• Fatigue
• Weight gain
• Brain fog
Dependencies
• Requires iodine, selenium
• Sensitive to stress & calorie restriction
Glucagon
• Released when blood glucose is low
• Signals liver to release stored glucose
Effects
• Maintains blood sugar
• Supports fasting energy
Leptin
• Released from fat cells
• Signals energy sufficiency to brain
Effects
• Reduces appetite
• Increases energy expenditure
Leptin Resistance
• Brain ignores signal → overeating
Ghrelin
• Released from stomach
Effects
• Stimulates hunger
• Increases before meals
Interaction
• Opposes leptin
😰 STRESS & ADAPTATION HORMONES
Cortisol
• Released via adrenal glands (HPA axis)
• Increases glucose availability
Short-Term Effects
• Energy boost
• Alertness
Chronic Effects
• Muscle breakdown
• Fat storage (especially abdominal)
• Sleep disruption
Interactions
• Suppresses testosterone
• Impacts insulin sensitivity
Epinephrine (Adrenaline)
• Rapid release during stress/exercise
Effects
• Increases heart rate
• Mobilizes energy
• Enhances performance
Norepinephrine
• Similar to adrenaline
• More focused on alertness and focus
😴 SLEEP & RECOVERY HORMONES
Melatonin
• Released in response to darkness
Effects
• Regulates circadian rhythm
• Initiates sleep
Interaction
• Suppressed by blue light
• Controls timing of other hormones
🧬 ADDITIONAL CRITICAL HORMONES
Aldosterone
• Regulates sodium & water balance
Effects
• Controls blood pressure
• Works closely with hydration
* Direct link to performance in heat/sweat
Antidiuretic Hormone (ADH / Vasopressin)
• Controls water retention in kidneys
* Prevents dehydration
Parathyroid Hormone (PTH)
• Regulates calcium levels
*Critical for:
• Muscle contraction
• Bone health
Calcitonin
• Opposes PTH
• Helps regulate calcium balance
Prolactin
• Involved in recovery and immune regulation
• Can suppress testosterone
Estrogen
• Not just female hormone
• Important for:
• Bone health
• Brain function
• Recovery
• Needs balance (not too high, not too low)
Progesterone
• Regulates reproductive system
• Supports nervous system balance
🔄 HORMONAL AXES (SYSTEM CONTROL)
HPA Axis
(Hypothalamus → Pituitary → Adrenal)
• Controls stress (cortisol)
HPT Axis
(Hypothalamus → Pituitary → Thyroid)
• Controls metabolism
HPG Axis
(Hypothalamus → Pituitary → Gonads)
• Controls testosterone, estrogen
* These axes coordinate everything
⚡ PERFORMANCE INTEGRATION
Strength & Muscle
• Testosterone
• IGF-1
• Insulin
Fat Loss
• Thyroid
• Insulin sensitivity
• Cortisol balance
Energy
• Thyroid
• Adrenal hormones
Recovery
• GH
• Sleep hormones
• Low chronic stress
HORMONES
📊 FULL LIST OF AMINO ACIDS (20 TOTAL)
ESSENTIAL (9) — must get from food
1. Leucine
2. Isoleucine
3. Valine
4. Lysine
5. Methionine
6. Phenylalanine
7. Threonine
8. Tryptophan
9. Histidine
NON-ESSENTIAL (11) — body can make them
10. Alanine
11. Asparagine
12. Aspartic acid
13. Glutamic acid
14. Serine
15. Glycine
16. Proline
17. Cysteine
18. Tyrosine
19. Glutamine
20. Arginine
* Note: Some of these become “conditionally essential” during stress, illness, or heavy training.
💪 BREAKDOWN OF EACH AMINO ACID
ESSENTIAL AMINO ACIDS
Leucine
• Turns on muscle protein synthesis
• Most important for building muscle
Isoleucine
• Helps muscles use glucose
• Supports recovery
Valine
• Helps reduce mental fatigue
• Supports muscle repair
Lysine
• Helps build muscle tissue
• Supports collagen formation
Methionine
• Helps process fats
• Important for liver health
Phenylalanine
• Converts to tyrosine ~ dopamine
• Supports focus & mood
Threonine
• Important for skin, cartilage
• Supports gut health
Tryptophan
• Converts to serotonin ~ melatonin
• Helps regulate sleep
Histidine
• Helps produce histamine
• Supports oxygen transport
——- NON-ESSENTIAL AMINO ACIDS
Alanine
• Helps regulate blood sugar
• Used during exercise
Asparagine
• Helps build proteins
• Supports nervous system
Aspartic Acid
• Helps produce ATP
• Supports testosterone production
Glutamic Acid
• Key neurotransmitter
• Supports energy pathways
Serine
• Important for brain function
• Helps produce cell membranes
Glycine
• Major part of collagen
• Helps improve sleep quality
Proline
• Critical for collagen
• Supports tissue repair
Cysteine
• Helps produce glutathione
• Protects cells from damage
Tyrosine
• Produces dopamine & adrenaline
• Improves mental performance
Glutamine
• Most abundant amino acid
• Supports gut and immune health
Arginine
• Produces nitric oxide
• Improves circulation
AMINO ACIDS
VO₂ max = the maximum amount of oxygen your body can use per minute
Measured as:
• mL of oxygen per kg of bodyweight per minute
Core equation:
VO_2 = Q \times (a - v)O_2
* This breaks VO₂ max into 2 components:
• Q (Cardiac Output) → how much blood you deliver
• (a-v)O₂ → how much oxygen muscles extract
The Oxygen Pipeline
VO₂ max depends on a chain:
1. Respiratory system → brings in oxygen
2. Cardiovascular system → transports oxygen
3. Blood → carries oxygen (hemoglobin)
4. Muscles → extract and use oxygen
5. Mitochondria → produce ATP
*Your VO₂ max is only as strong as the weakest link in this chain
VO₂ Max Limits
Central Limit ~ Cardiac output (Q)
Q = HR \times SV
• HR = heart rate
• SV = stroke volume
*Stroke volume is the biggest limiter
• Bigger, stronger heart → higher VO₂ max
Peripheral Limit
• Capillary density
• Mitochondrial density
• Muscle oxidative capacity
* Determines how much oxygen muscles can use
Oxygen Carrying Capacity
• Hemoglobin levels
• Blood volume
Respiratory System
• Usually NOT the main limiter
• Only becomes limiting at elite levels
VO₂ Max vs Performance
***High VO₂ max ≠ automatically elite performance
Because performance also depends on:
• Lactate threshold
• Movement efficiency
• Fuel utilization
Lactate Threshold
The intensity where lactate accumulates faster than it can be cleared
*Determines how much of your VO₂ max you can actually use
Example:
• Person A: High VO₂ max, low threshold → poor endurance
• Person B: Moderate VO₂ max, high threshold → better endurance
* Threshold often matters MORE than VO₂ max
Ventilatory Threshold (VT1 & VT2)
Closely tied to lactate:
• VT1 → aerobic threshold (easy/moderate pace)
• VT2 → anaerobic threshold (hard effort)
* Used to define training zones
Movement Economy
How much oxygen you use at a given workload
* Better economy = less energy used
Influenced by:
• Technique
• Neuromuscular coordination
• Biomechanics
*Elite athletes are efficient, not just powerful
V02 MAX
Central Nervous System (CNS)
The CNS is not just a “processor”—it’s a predictive command center.
Brain regions (functional specialization):
• Cerebral cortex → conscious thought, voluntary movement, planning
• Motor cortex → initiates movement patterns
• Somatosensory cortex → processes touch, pressure, proprioception
• Cerebellum → coordination, timing, motor learning (critical for skill + lifting efficiency)
• Basal ganglia → habit formation, movement efficiency, automaticity
• Brainstem → life support (breathing, heart rate, blood pressure)
* In training terms:
• Cortex = intent
• Cerebellum = precision
• Basal ganglia = efficiency (automatic reps)
Spinal Cord
More than a relay—it’s a real-time processor.
• Handles reflex arcs (no brain needed for speed)
• Integrates sensory + motor signals locally
• Enables rate of force development (RFD) via rapid motor neuron firing
Peripheral Nervous System
A.Somatic Nervous System (Voluntary)
• Controls skeletal muscle
• Uses alpha motor neurons to trigger contraction
B. Autonomic Nervous System (ANS)
Regulates internal environment (homeostasis)
Sympathetic (SNS) — “Mobilization”
• Increases:
• Heart rate
• Blood pressure
• Blood glucose
• Neural drive
• Releases:
• Norepinephrine
• Epinephrine
* Training link:
High-intensity lifting, sprinting = SNS dominant
Parasympathetic (PNS) — “Recovery”
• Decreases heart rate
• Enhances digestion
• Promotes tissue repair
• Dominated by the vagus nerve
* Training link:
Recovery, sleep, growth = PNS dominant
The Neuron
• Dendrites → receive signals
• Cell body (soma) → processes
• Axon → transmits electrical signal
• Myelin sheath → increases speed (up to 100x faster conduction)
Electrical Signaling — Action Potentials
Neurons fire via electrochemical gradients:
• Resting potential ≈ -70 mV
• Depolarization → Na⁺ influx
• Repolarization → K⁺ efflux
* This creates an action potential (all-or-nothing signal)
Synaptic Transmission
Communication between neurons:
• Electrical signal → chemical signal
• Neurotransmitters released into synapse
• Bind to receptors on next neuron
Major Neurotransmitters:
Excitatory:
• Glutamate → increases firing
Inhibitory:
• GABA → decreases firing
Modulators:
• Dopamine → motivation, reward, motor control
• Acetylcholine → muscle contraction
• Serotonin → mood, recovery, sleep
• Norepinephrine → alertness, focus
Motor Unit Recruitment
A motor unit = motor neuron + muscle fibers it controls
Size Principle:
Motor units are recruited from smallest → largest:
1. Low-threshold → endurance fibers (Type I)
2. Mid-threshold → mixed fibers
3. High-threshold → power fibers (Type II)
* High-threshold units = biggest growth + strength potential
***To maximize hypertrophy:
• You must recruit high-threshold motor units
• This happens via:
• Heavy load
• High effort (close to failure)
• Explosive intent
Rate Coding
Force is not just recruitment—it’s also firing frequency:
• Low frequency → weak contraction
• High frequency → stronger contraction (summation → tetanus)
* Elite strength =
• High recruitment
• High firing rate
• Precise synchronization
Neuroplasticity
The nervous system rewires itself based on use.
Mechanisms:
• Synaptic strengthening (long-term potentiation)
• Increased myelination
• Improved motor pattern efficiency
* This is why:
• Skill improves with repetition
• Lifting technique becomes automatic
• Early strength gains are mostly neural
Fatigue — Central vs Peripheral
Central Fatigue (CNS)
• Reduced neural drive from brain
• Decreased motor unit recruitment
• Linked to:
• Stress
• Poor sleep
• Overtraining
Peripheral Fatigue (Muscle)
• Metabolite buildup (H⁺, Pi)
• Reduced calcium release
• Energy depletion (ATP)
* You can feel “tired” before muscles are truly maxed
That’s CNS protection
Reflexes & Protective Mechanisms
Muscle Spindle
• Detects stretch
• Triggers contraction (stretch reflex)
* Helps explosive movement (plyometrics)
Golgi Tendon Organ (GTO)
• Detects tension
• Inhibits contraction when too high
* Limits force output (safety mechanism)
Training can desensitize GTO → higher force potential
Nervous System & Energy Efficiency
• Minimize energy use
• Maximize output efficiency
• Better motor unit coordination
• Reduced unnecessary muscle activation
• Improved movement economy
* This is why trained athletes:
• Use less energy for same work
• Look “smooth” and efficient
NERVOUS SYSTEM
Gross Structure
• Diaphysis - shaft (dense, strong)
• Epiphysis - ends (spongy, shock-absorbing)
• Periosteum - outer layer (where tendons/ligaments attach)
• Medullary cavity - marrow storage
Bone Tissue Types
Cortical (Compact Bone)
• Dense, rigid
• High strength
• Handles heavy loads
Trabecular (Spongy Bone)
• Porous, lattice-like
• Absorbs force
• Found in joints and vertebrae
* Heavy lifting increases bone density, especially cortical bone.
Microscopic Structure
• Osteons (Haversian systems) → structural units
• Osteocytes → mature bone cells
• Osteoblasts → build bone
• Osteoclasts → break down bone
* Constant remodeling = bone is alive and adaptive
Bone Remodeling
1. Osteoclasts break down old bone
2. Osteoblasts build new bone
Wolff’s Law
*** Bone adapts to the stress placed on it
• More load - stronger, denser bone
• Less load - bone loss
Training Implications:
• Resistance training - bone density
• Impact training (jumping, sprinting) - structural strength
• Sedentary lifestyle - bone loss
Types of Bones
Long Bones
• Femur, humerus
• Built for movement and leverage
Short Bones
• Carpals, tarsals
• Stability + shock absorption
Flat Bones
• Skull, ribs
• Protection
Irregular Bones
• Vertebrae
• Complex functions
Sesamoid Bones
• Patella
• Improve force transmission
Joints
Structural Classification:
Fibrous (Immovable)
• Skull sutures
Cartilaginous (Slight movement)
• Spine discs
Synovial (Freely movable)
* Most important for training
Synovial Joint Components
• Articular cartilage - reduces friction
• Synovial fluid - lubrication
• Joint capsule - stability
• Ligaments - connect bone to bone
Types of Synovial Joints
Hinge
• Knee, elbow
• Flexion/extension
Ball-and-Socket
• Hip, shoulder
• Multi-directional movement
Pivot
• Neck rotation
Saddle
• Thumb
Condyloid
• Wrist
Gliding
• Small sliding joints
Connective Tissue
Ligaments
• Bone - bone
• Provide stability
• Poor blood supply - slow healing
Tendons
• Muscle - bone
• Transmit force
• Can store elastic energy
Cartilage
• Reduces friction
• Absorbs shock
• Limited healing capacity
Movement & Leverage
Bones act as levers with 3 Classes:
First-Class
• Neck (balance)
Second-Class
• Calf raise (power)
Third-Class
• Bicep curl (speed, range)
*** The body sacrifices force for speed and range of motion
SKELETAL SYSTEM
The cardiovascular system is primarily a transport and regulation network.
Primary roles:
• Deliver oxygen (O₂) to working tissues
• Remove carbon dioxide (CO₂) and waste
• Transport:
• Nutrients (glucose, fatty acids, amino acids)
• Hormones
• Electrolytes
• Regulate:
• Body temperature
• pH (acid-base balance)
• Blood pressure
Major Components
Heart - a four-chamber muscular pump.
Chambers:
• Right atrium
• Right ventricle
• Left atrium
• Left ventricle (most powerful)
Blood Flow Pathway:
1. Body - Right atrium (deoxygenated blood)
2. - Right ventricle
3. - Lungs (via pulmonary artery)
4. - Left atrium (oxygenated blood)
5. - Left ventricle
6. - Body (via aorta)
Valves (One-Way Flow)
• Tricuspid
• Pulmonary
• Mitral (bicuspid)
• Aortic
* Prevent backflow - maintain pressure and efficiency
Blood Vessels
Arteries
• Carry blood away from heart
• High pressure
• Thick, elastic walls
Veins
• Carry blood back to heart
• Lower pressure
• Contain valves
Capillaries
• Microscopic vessels
• Site of gas and nutrient exchange
Blood Components:
• Plasma (fluid)
• Red blood cells (RBCs) → carry oxygen via hemoglobin
• White blood cells → immune defense
• Platelets → clotting
Key Cardiovascular Metrics
Heart Rate (HR)
• Beats per minute
• Resting HR = efficiency indicator
Stroke Volume (SV)
• Blood pumped per beat
Cardiac Output (Q)
Q = HR \times SV
* Total blood pumped per minute
Blood Pressure (BP)
• Systolic (contraction)
• Diastolic (relaxation)
* Performance = ability to increase cardiac output efficiently
Oxygen Delivery System
This is where everything connects to performance
VO₂ (Oxygen Consumption)
VO_2 = Q \times (a - v)O_2
• Q = cardiac output
• (a-v)O₂ = oxygen extracted by muscles
Performance depends on:
1. How much blood you deliver
2. How much oxygen muscles can extract
Acute Response to Exercise
Increases:
• Heart rate
• Stroke volume
• Cardiac output
• Blood flow to muscles
• Systolic BP
Decreases:
• Blood flow to non-essential systems (digestive, etc.)
Blood Redistribution:
• Muscles get priority
• Skin increases flow (cooling)
Aerobic vs Anaerobic Systems
Aerobic (Oxygen-based)
• Fat + carbs as fuel
• Sustainable
• Lower intensity
Anaerobic (No oxygen required)
• Fast energy
• Limited duration
• Produces fatigue quickly
Lactate Threshold
• Point where lactate accumulates faster than cleared
• Determines endurance performance
• Trainable via:
• Tempo work
• Threshold training
Cardiovascular Efficiency
• Low resting HR
• High stroke volume
• Fast recovery HR
* Heart rate recovery (HRR)
• Faster drop post-exercise = better conditioning
Blood Pressure & Health
Normal:
• ~120/80 mmHg
Hypertension (High BP)
• Increased strain on heart
• Major risk factor for:
• Heart disease
• Stroke
Training Considerations:
• Avoid excessive valsalva
• Use moderate intensity
• Emphasize aerobic work
Thermoregulation
The cardiovascular system helps regulate temperature:
• Vasodilation → heat loss
• Vasoconstriction → heat conservation
• Sweat response supported by blood flow
CARDIOVASCULAR SYSTEM
The respiratory system is responsible for:
• Bringing in oxygen (O₂)
• Removing carbon dioxide (CO₂)
• Regulating blood pH (acid-base balance)
• Supporting energy production (ATP)
Anatomy (Airflow Pathway)
1. Nose / nasal cavity
2. Pharynx
3. Larynx
4. Trachea
5. Bronchi
6. Bronchioles
7. Alveoli (critical site)
Alveoli (Where Performance Happens)
• Tiny air sacs (~300 million)
• Surrounded by capillaries
• Massive surface area (~70 m²)
* This is where gas exchange occurs
Mechanics of Breathing
Inhalation
• Diaphragm contracts → moves downward
• Thoracic cavity expands
• Pressure drops → air flows in
Exhalation
• Diaphragm relaxes
• Lungs recoil
• Air is pushed out
Key Muscles
• Diaphragm (primary)
• Intercostals (rib movement)
• Accessory muscles (during intense breathing)
Gas Exchange
At the alveoli:
• Oxygen diffuses into blood
• Carbon dioxide diffuses out
Driven by partial pressure gradients
Hemoglobin Binding
• Oxygen binds to hemoglobin in red blood cells
• Transported to muscles
Bohr Effect (Performance Insight)
• Higher CO₂ + acidity → oxygen released more easily to muscles
* This is GOOD during exercise
Respiratory Volumes
Tidal Volume (TV)
• Normal breath
Vital Capacity (VC)
• Max inhale → max exhale
Residual Volume (RV)
• Air left after exhale
Minute Ventilation (VE)
VE = TV \times RR
• TV = tidal volume
• RR = respiratory rate
During Exercise:
• Both TV and RR increase
• Massive increase in oxygen delivery
Respiratory & Energy Systems
ATP-PC
• No oxygen needed
Glycolytic
• Limited oxygen involvement
Oxidative
*** Fully dependent on respiratory system
VO₂ Max Connection
Respiratory system supplies oxygen for:
VO_2 = Q \times (a - v)O_2
* If oxygen intake is limited → performance drops
Respiratory Fatigue
• Breathing muscles fatigue
• Compete for blood flow with limbs
* Can limit endurance performance
Oxygen vs Carbon Dioxide
Most people think breathing is about oxygen…
*** It’s equally about removing CO₂
• CO₂ buildup → acidity
• Affects muscle contraction
• Impacts fatigue
pH Regulation
Normal blood pH ≈ 7.4
During exercise:
• CO₂ ↑ → acidity ↑
• Breathing ↑ to compensate
Respiratory system helps maintain balance
RESPIRATORY SYSTEM
Planes of motion are imaginary 2D slices that divide the body and describe how movement occurs in 3D space.
The 3 Primary Planes:
Sagittal, Frontal, Transverse
Sagittal Plane (Front ↔ Back)
Divides the body into:
• Left
• Right
Primary Movements:
• Flexion
• Extension
Examples:
• Squat
• Deadlift
• Bicep curl
• Running
Joint Actions:
• Elbow flexion/extension
• Knee flexion/extension
• Hip hinge
* Most people OVERTRAIN this plane
• Traditional gym training = sagittal dominant
• Leads to imbalances if others are ignored
Frontal Plane (Side ↔ Side)
Divides the body into:
• Front (anterior)
• Back (posterior)
Primary Movements:
• Abduction (away from midline)
• Adduction (toward midline)
Examples:
• Lateral raises
• Side lunges
• Jumping jacks
• Lateral shuffles
Joint Actions:
• Shoulder abduction
• Hip abduction/adduction
*Critical for:
• Stability
• Injury prevention (especially knees/hips)
Transverse Plane (Rotational)
Divides the body into:
• Upper
• Lower
Primary Movements:
• Rotation
• Internal/external rotation
Examples:
• Russian twists
• Golf swing
• Throwing
• Punching
Joint Actions:
• Spinal rotation
• Shoulder rotation
• Hip rotation
* Most athletic power is rotational
Real Movement = Multiplanar
Almost no real-world movement is purely one plane.
Example: Walking
• Sagittal → leg movement
• Frontal → balance
• Transverse → torso rotation
Example: Squat
• Mostly sagittal
• BUT includes:
• Frontal stabilization
• Transverse control
Plane-Specific Muscle Emphasis
Sagittal Plane:
• Quads
• Hamstrings
• Glutes
• Biceps
Frontal Plane:
• Glute medius
• Adductors
• Abductors
Transverse Plane:
• Obliques
• Rotator cuff
• Deep hip rotators
Programming Based on Planes
Sagittal:
• Squat
• Hinge
• Push/pull
Frontal:
• Lateral lunges
• Side steps
• Single-leg work
Transverse:
• Rotational core work
• Anti-rotation exercises
Injury & Dysfunction Patterns
Sagittal Dominance Leads To:
• Tight hip flexors
• Weak glute med
• Knee valgus (collapse inward)
Poor Frontal Plane Strength:
• ACL injury risk
• Hip instability
Poor Transverse Control:
• Low back pain
• Poor force transfer
PLANES OF MOTION
Open Kinetic Chain
* The distal segment (hand/foot) is free to move
• Movement happens at one primary joint
• Body is not fixed
Examples:
• Leg extension
• Bicep curl
• Seated hamstring curl
• Dumbbell shoulder press
Closed Kinetic Chain
* The distal segment is fixed (usually against ground or surface)
• Multiple joints move together
• Body moves around the fixed point
Examples
• Squat
• Push-up
• Pull-up
• Deadlift
• Lunges
Open Chain:
• Isolated joint movement
• External load moves through space
• Less stabilization required
Closed Chain:
• Multi-joint movement
• Body moves as a system
• High stabilization demand
Muscle Recruitment Patterns
Open Chain:
• Targets specific muscles
• Less co-contraction
• Easier to isolate weak areas
* Example:
Leg extension - mostly quads
Closed Chain:
• High co-contraction (multiple muscles working together)
• Greater joint stability
• More “real-world” strength
* Example:
Squat - quads + glutes + hamstrings + core
Joint Stress & Safety
Open Chain:
• Can place higher stress on a single joint
• Less joint stability
• More shear force
* Example:
Leg extension - high stress on knee joint
Closed Chain:
• Distributes force across joints
• More compressive (stable) forces
• Generally safer for joints
* CKC = more joint-friendly (in most cases)
* OKC = more targeted but potentially higher stress
Neuromuscular Demand
Open Chain:
• Lower coordination requirement
• Easier to learn
• Good for beginners
Closed Chain:
• High coordination
• Requires balance + stability
• Engages nervous system more
* CKC builds movement intelligence
* OKC builds muscle specificity
Functional Transfer
Open Chain:
• Less carryover to real-world movement
• Good for:
• Rehab
• Muscle isolation
Closed Chain:
• High transfer to:
• Sports
• Daily life
• Performance
Core Activation
Open Chain:
• Minimal core demand
Closed Chain:
• High core engagement
• Requires stabilization of spine
* Example:
Push-up vs bench press
Push-up demands more full-body stability
Rehab & Corrective Use
Open Chain:
• Early-stage rehab
• Isolate weak or injured muscles
• Controlled environment
Closed Chain:
• Later-stage rehab
• Restore movement patterns
• Improve joint stability
Example Progression:
• Knee rehab:
1. Leg extension (OKC)
2. Bodyweight squat (CKC)
3. Single-leg squat (advanced CKC)
Strength & Hypertrophy Application
For Hypertrophy:
* Combine both
• OKC → isolate and fatigue muscle
• CKC → load heavy and recruit more fibers
For Strength:
* Prioritize CKC
• Greater load potential
• Better neural adaptation
For Muscle Imbalances:
* Use OKC strategically
• Fix weak links
• Improve symmetry
Force Production Differences
Open Chain:
• Force peaks at specific joint angles
• Less overall force production
Closed Chain:
• Higher total force output
• Better force distribution
Stability & Balance
Open Chain:
• Low stability demand
Closed Chain:
• High stability demand
• Trains:
• Balance
• Proprioception
• Joint control
Sport-Specific Relevance
Open Chain:
• Throwing
• Kicking
Closed Chain:
• Running
• Jumping
• Cutting
• Lifting
* Most sports = CKC dominant