Exercise Sciences: Mechanisms That Drive Coaching Decisions
Exercise Sciences is the anatomy, physiology, biomechanics, and endocrine foundation the CSCS exam uses to explain why training works. Expect items that connect a mechanism to a coaching decision rather than isolated definitions.
Muscle and motor control
- Sarcomere shortening uses actin-myosin cross-bridges; force depends on the length-tension and force-velocity relationships.
- Fiber types: I (slow oxidative), IIa (fast oxidative-glycolytic), and IIx (fast glycolytic). The Henneman size principle recruits low-threshold motor units first.
- The stretch-shortening cycle has eccentric, amortization, and concentric phases; a short, stiff amortization improves plyometric output.
Energy and cardiovascular response
- The phosphagen system dominates brief maximal efforts (about 0-10 s); glycolysis contributes heavily from roughly 10 s to 2 min; oxidative metabolism dominates longer work.
- Cardiac output = heart rate x stroke volume. Resistance exercise raises blood pressure acutely, so breathing and load choice matter.
- Acute resistance training raises anabolic hormones such as testosterone and growth hormone, but the response is modest and should not replace progressive overload as the design driver.
Biomechanics
- Torque = force x moment arm. Small changes in bar path or limb position change joint torque substantially.
Worked example
A 500 N load is held 0.20 m horizontally from the knee joint: torque = 500 x 0.20 = 100 Nm. If the bar drifts forward to 0.30 m, torque = 500 x 0.30 = 150 Nm, a 50% increase from a 10 cm shift. That is why a coach cues bar over midfoot rather than only stand up.
Traps
Confusing a muscle action with a joint action; assuming soreness proves a good stimulus; thinking low-intensity exercise uses only fat; ignoring the size principle when prescribing explosive work.