ISSA Applied Science – Comprehensive Bullet-Note Guide

Applied Science – Study Guide Overview

"Applied Science" = foundation for all personal-fitness applications → integrates anatomy, physiology, kinesiology & biomechanics.
Core idea: Master structure/function of nervous, muscular & skeletal systems ➔ then link principles to any new training style.

Hierarchy of the Human Body

Organizational order: Atoms → Cells → Tissues → Organs → Organ Systems → Organism
11 organ systems; movement-centric: Nervous (master control), Muscular (engine), Skeletal (framework).

Nervous System (Ch. 3)

General Functions

Governs voluntary & involuntary body actions, integrates sensory input, initiates motor output.
Key outputs: sensory impulses, integrative processing, motor function.

Micro-Anatomy Terminology

Neuron (nerve cell) parts
- Cell body (nucleus & organelles)
- Dendrites (receive signals)
- Axon (conducts impulses)
Neuroglia = support & insulate neurons.
Neurosecretory tissue → converts neural signals into hormones.
Myelin sheath = lipid + protein insulation for faster propagation.
Decussation = crossover point (medulla ↔ spinal cord).
Homeostasis controlled largely by hypothalamus.

Neuron Classifications

Sensory (afferent) – convey touch, sound, light, etc.
Motor (efferent) – trigger muscle/gland action.
Interneurons – connect neuron-to-neuron.

Brain Lobes & Cortices

Frontal (motor control, emotion, language)
- Motor cortex & prefrontal cortex.
Parietal (sensory) – somatosensory cortex.
Temporal (hearing/memory) – auditory cortex.
Occipital (vision) – visual cortex.

CNS vs PNS

CNS = brain + spinal cord
- Cerebrum, cerebellum (conscious motor coordination), brain stem (midbrain, pons, medulla), thalamus, spinal cord.
PNS = cranial & spinal nerves + ganglia
- Afferent vs efferent.
- Reflex arcs processed in spinal cord.
Somatic NS → voluntary; Autonomic NS → involuntary
- Sympathetic ("fight-or-flight") vs Parasympathetic ("rest-and-digest").

Receptors & Sensory Concepts

Mechanoreceptors (tactile, proprioceptors, baroreceptors).
Proprioception = body-position awareness.

Motor Unit Concepts

Motor unit = α-motor neuron + its extrafusal fibers.
All-or-none principle for action potentials.
Size principle (Henneman): recruit small→large, slow→fast.

Muscular System (Ch. 3)

Types of Muscle Tissue

Tissue	Structure	Control	Example
Cardiac	Striated	Involuntary	Heart wall
Smooth	Smooth	Involuntary	Digestive organs
Skeletal	Striated	Voluntary; fatigues easily	Majority of body movement

Skeletal Muscle Micro-Structure

Sarcomere – contractile unit; Z-lines mark ends.
Myofilaments = actin (thin) & myosin (thick).
Sarcoplasm (cytoplasm), glycogen storage, myofibrils.
Connective sheaths: endomysium (fiber), perimysium (fascicle), epimysium (whole muscle); tendon connects to periosteum.

Neuromuscular Mechanics

Brain electrical signal → spinal cord → motor neuron.
Acetylcholine released at neuromuscular junction.
$Ca^{2+}$ binds actin → myosin heads "walk" using ATP.
Sliding-filament shortens sarcomere → contraction.

Excitation-contraction coupling links nerve impulse to mechanical work.

Fiber Types

Type I (slow-twitch, aerobic, endurance).
Type IIa (fast, moderate fatigue, moderate mitochondria).
Type IIx (fastest, fast-fatigable, low mitochondria, white).
Size principle defines recruitment order.

Muscle Actions

Concentric (shorten), Eccentric (lengthen), Isometric (static).
Stretch-shortening cycle = eccentric → amortization → concentric.

Roles in Movement

Agonist (prime mover), Antagonist (opposite), Synergist (assist), Stabilizer.
Sherrington’s law: activation ↔ inhibition of opposite muscle.

Fiber Arrangements

Fusiform (biceps), Convergent (pectoralis), Circular, Parallel, Uni/Bi/Multi-pennate, etc.

Skeletal System (Ch. 3)

Divisions & Counts

≈206 bones total.
Axial (80): skull, spine, ribs.
Appendicular (126): limbs + girdles.

Bone Categories & Examples

Flat (ribs), Short (carpals), Long (femur), Sesamoid (patella), Irregular (vertebrae).

Micro-Structure & Physiology

Cancellous (spongy) vs Compact (cortical).
Bone marrow houses stem cells.
Osteogenesis (bone formation) guided by Wolff’s law (adapt to loads).
Myositis ossificans = bone forms in muscle post-trauma.

Joints (Ch. 3)

Fibrous (sutures, syndesmosis, gomphosis) – minimal motion.
Cartilaginous (epiphyseal, intervertebral discs) – moderate motion.
Synovial – freely movable; sub-types: Gliding, Hinge, Pivot, Condyloid, Saddle, Ball-and-socket.
Arthrokinematics = joint motion; close- vs loose-packed positions.

Tendons, Ligaments & Cartilage

Tendons

Muscle→bone force bridge.
Proprioceptors: Golgi tendon organs (tension) & muscle spindles (length change).

Ligaments

Bone→bone stabilizers; types: Extrinsic (e.g., LCL), Intrinsic (ACL), Capsular (MCL).
Varus (away from midline) vs Valgus (toward midline) stresses.

Cartilage

Hyaline (articular surfaces), Fibrocartilage (meniscus), Elastic (ear, epiglottis).
Avascular/anervous → slow healing.
Perichondrium surrounds cartilage; nociceptors detect pain.

Supportive Systems (Ch. 4)

Circulatory

Heart facts: ~100 000 beats/day; pumps 5-6 qt/min at rest.
Pathway: body → RA → RV → lungs → LA → LV → body.
Cardiac cycle phases: Systole (contraction), Diastole (filling).
$BP = \frac{\text{systolic}}{\text{diastolic}}$ ; normal $120/80\,\text{mm Hg}$ .
Stroke volume, HR, cardiac output affect pressure.
Blood cells: erythrocytes, five WBC types (basophil, neutrophil, eosinophil, monocyte, lymphocyte).

Lymphatic

Structures: nodes, tonsils, spleen, thymus.
Balances fluids, absorbs fats, immune defense; fluid = lymph.

Respiratory

Path: nose → pharynx → larynx → trachea → bronchi → lungs → alveoli.
Key terms: inspiration, expiration, pulmonary ventilation, diffusion.
Diaphragm = prime mover.
External vs internal respiration (lungs↔blood vs blood↔cells).

Endocrine

Glands: hypothalamus, pineal, pituitary, thyroid, parathyroid, thymus, adrenals, pancreas, ovaries, testes.
Hormone table (GH, TSH, ACTH, etc.) – many ↑ with exercise intensity.
Exercise hormones: testosterone (anabolic), GH, IGF-1, insulin (glucose uptake), cortisol (stress; short- vs long-term), catecholamines (epi, norepi).
Endocrine (ductless, internal) vs Exocrine (ducts, external).

Digestive

GI tract: mouth (mastication→bolus) → esophagus → stomach (chyme) → small intestine (duodenum, jejunum, ileum) → large intestine/rectum.
Accessory: liver (bile, detox, metabolism), gallbladder (stores bile), pancreas (enzymes amylase, lipase, etc.).
Processes: ingestion, mechanical & chemical digestion, peristalsis, absorption (villi), elimination.

Integumentary

Skin, hair, nails; layers: epidermis, dermis, hypodermis.
Functions: protect organs, prevent fluid loss, thermoregulation.

Biomechanics & Kinesiology (Ch. 5)

Key Physical Quantities

Force $F = m \times a$
Work $W = F \times D$
Power $P = \frac{W}{t} = F \times v$
Torque $\tau = F \times \text{force arm}$
Momentum $= m \times v$
Center of gravity & line of gravity; base of support governs stability.
Joint mobility vs stability – alternate pattern along kinetic chain.
Length-tension & force-couple relationships; muscle synergies.

Motion Types

Linear vs Angular; displacement vs distance; velocity vs acceleration; rotary motion.

Newton’s Laws

Inertia (object resists change).
$F = m a$ ; force-velocity & force-distance work formulas.
- Acceleration equation $a = \frac{\Delta v}{\Delta t}$
Action-reaction; ground-reaction forces govern gait & lifts.

Friction (static, sliding, rolling), compression, tension, shear.

Levers

Parts: fulcrum, effort arm, resistance arm, moment arm.
Classes: 1st (neck extension), 2nd (calf raise), 3rd (biceps curl) – majority in body are 3rd-class; $\text{MA} = \frac{\text{force arm}}{\text{resistance arm}}$ .

Planes & Axes

Sagittal (flexion/extension), Frontal (ab/adduction, side lunge), Transverse (rotation).
Anatomical terms: anterior/posterior, proximal/distal, medial/lateral, etc.
Movements list: abduction, plantarflexion, pronation, etc. (see transcript for full definitions).

Balance

Static vs dynamic; equilibrium when net forces = 0.

Kinetic Chain Checkpoints

Foot/Ankle (tibialis ant., gastrocnemius/soleus) – flex/extend, invert/evert.
Knee (quad, sartorius, gracilis, TFL, hamstrings) – hinge.
Hips – multi-planar; key for LPHC stability.
Spine – multiple planes; supported by core musculature.
Shoulder (ball-and-socket) – SITS rotator cuff.
Head/Neck – indicates chain alignment.

Cellular & Energy Systems (Ch. 6)

Cell Components Relevant to Metabolism

Mitochondria = aerobic ATP factory (Krebs + ETC).
Cytoplasm houses anaerobic glycolysis.
Ribosomes (protein synthesis), ER, Golgi, lysosomes.

Bioenergetics Terminology

ATP hydrolysis: $ATP \rightarrow ADP + P + H^+ + \text{energy}$
Creatine phosphate donates P: $CP + ADP \rightarrow ATP + C$
Anaerobic threshold & lactate threshold (onset of blood lactate).
Respiratory quotient $RQ = \frac{V{CO2}}{V{O2}}$ (1.0 carbs; 0.7 fats).
Indirect calorimetry measures O2/CO2 to estimate expenditure.

Energy Pathways

System	O2?	Dominant Duration	Rate	ATP Yield
ATP-CP	No	\<10 s	Fastest	Small
Anaerobic Glycolysis	No	10 s – 2 min	Fast	Moderate; produces lactate
Oxidative (Krebs + ETC, β-oxidation)	Yes	>2 min	Slow	Largest

Macronutrient Energy

Carbs 4 Cal/g, Protein 4 Cal/g, Fat 9 Cal/g.
Resting mix ≈70 % fat / 30 % carb.
Gluconeogenesis converts non-carb substrates to glucose under fasting/high-protein intake.

Energy Balance & Calculations

TDEE = RMR (≈70 %) + TEF + EAT + NEAT + growth.
RMR (Mifflin/Bland-Altman):
- Men $=66.473 + 13.7516W{kg} + 5.0033H{cm} - 6.7550A$
- Women $=655.0955 + 9.5634W{kg} + 1.8496H{cm} - 4.6756A$
DCE (Harris-Benedict) multiplies by Activity Level Factor $ALF$ values (1.2–1.9).
Surplus (+200-500 Cal) → muscle gain; Deficit (-200-500 Cal) → fat loss.

Somatotypes

Ectomorph (lean) – may need higher carb/protein.
Mesomorph (athletic) – balanced macros.
Endomorph (thicker) – lower carbs, higher protein.

Acute & Chronic Exercise Adaptations (Ch. 9)

Anaerobic Training Increases

Muscle strength & size, sprint speed, power, fast-twitch fiber size, stored CP/ATP/glycogen; bone/tendon strength.
Neural adaptations drive early strength gains.

Aerobic Training Increases

VO$_2$max, capillary & mitochondrial density, stroke volume, fat utilization; lowers resting HR & BP.
Both modalities ↓ bodyfat % & can ↑ tendinous strength.

High-Yield Equation Summary

$F = m a$
$W = F D$
$P = \frac{W}{t} = F v$
$\tau = F \times \text{force arm}$
$RQ = \frac{V{CO2}}{V{O2}}$
RMR (men): $66.473 + 13.7516W + 5.0033H - 6.7550A$
RMR (women): $655.0955 + 9.5634W + 1.8496H - 4.6756A$

Practical & Ethical Implications

Understanding foundational science allows trainers to adopt evidence-based trends safely.
Awareness of endocrine & stress responses (e.g., chronic cortisol) guides program design to promote health not harm.
Knowledge of joint anatomy (close-packed vs loose-packed) informs safe exercise selection & progression.
Recognizing proprioceptive feedback & kinetic-chain checkpoints aids in correcting dysfunctional movement patterns, thereby reducing injury risk.