Open, evidence-based learning
The science of the human body, training and performance — explained properly.
From the sarcomere to the season plan. Every lesson explains what, why and how, shows the mechanism with original diagrams, and traces each important claim back to its research.
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Learning pathways
Beginner: How the body moves and makes energy
No prior knowledge. Learn the language of anatomy, how muscle works and how the body fuels exercise.
8 steps · 8 available
IntermediateEndurance science: from heart to performance
Cardiac output, VO₂ max, thresholds and intensity control — the science behind aerobic training.
9 steps · 8 available
IntermediateUnderstanding the squat
Everything connected to one movement: hip, knee and ankle anatomy, mechanics, assessment, loading and injury prevention.
11 steps · 10 available
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Featured scientific explainer
Energy systems never switch on one at a time
Popular fitness content often says the aerobic system “kicks in” after a few minutes. Research reviews show all three systems contribute from the first second, and aerobic metabolism supplies about half the energy in a maximal effort lasting roughly 75 seconds.
Read the lesson →Energy systems overview: how the body makes ATP
The phosphagen, glycolytic and oxidative systems — how each resynthesises ATP, how fast and for how long, and why they always work together rather than in sequence.
Aerobic Fitness and IntensityVO₂ max
What maximal oxygen uptake is, how it is measured and estimated, what limits it, how trainable it is, and why it matters for both performance and long-term health.
Muscle PhysiologyMuscle physiology: excitation–contraction and the sliding filament model
How a nerve signal becomes muscle force — from the neuromuscular junction to calcium release, cross-bridge cycling and the length–tension relationship.
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Most-used lessons
Energy systems overview: how the body makes ATP5 min VO₂ max5 min Heart rate zones and RPE-based intensity control5 min Concentric, eccentric and isometric muscle actions5 min Anatomical terminology, planes, axes and movement directions6 min Stroke volume, heart rate and cardiac output5 minRecently added
New and updated
Anatomical terminology, planes, axes and movement directionsHuman Anatomy 2026-10-31 The ankle and foot complex
Human Anatomy 2026-10-31 Bone structure, remodelling and adaptation to loading
Human Anatomy 2026-10-31 Cervical and thoracic spine functional anatomy
Human Anatomy 2026-10-31 Core and pelvic stability
Human Anatomy 2026-10-31 Elbow and wrist functional anatomy
Human Anatomy 2026-10-31
New to exercise science?
Eight lessons that take you from anatomical terminology to energy systems and intensity — no prior knowledge needed.
Start learning Professional pathwayCoaching clients or athletes?
Scope of practice, screening, assessment, programming and special populations, ordered for professional development.
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Recommended video lessons
Marked “needs verification” until reviewed by a person; unverified links open a YouTube search.
Anatomical position, directional terms and planes (introductory overview)
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The ankle and foot complexAnkle and foot anatomy
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Cervical and thoracic spine functional anatomyCervical spine anatomy
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Core and pelvic stabilityWhat is the core? Anatomy and function
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