Exercise Physiology, Anatomy, and Kinesiology
What to know
Bioenergetics. The ATP-PC system dominates very short, very intense work (roughly 0–10 s); fast glycolysis covers ~10 s to 2 min; oxidative metabolism dominates longer, lower-intensity efforts. Intensity, not duration alone, decides which system leads.
Muscle. Type I fibers are slow, oxidative, capillary- and mitochondria-rich, and fatigue resistant. Type IIx fibers are fast, glycolytic, powerful, and fatigue quickly; Type IIa sit between. During the sliding-filament cycle, thin actin filaments slide over thick myosin toward the M line - the sarcomere shortens, but the filaments themselves do not change length, and cross-bridge cycling requires both ATP and calcium.
Muscle actions and planes. Concentric shortens, eccentric lengthens (highest force capability, low metabolic cost, most associated with delayed soreness), isometric holds length. Sagittal = flexion/extension and running; frontal = abduction/adduction and jumping jacks; transverse = rotation and horizontal adduction.
Acute and chronic responses. Aerobic exercise raises HR, stroke volume, and cardiac output (Q = HR × SV); systolic pressure rises while diastolic stays about the same or dips slightly. Training lowers resting HR, raises stroke volume and plasma volume, and increases capillary and mitochondrial density; resistance training adds contractile protein per the SAID principle.
Traps
- Claiming filaments shorten or lengthen instead of sliding.
- Swapping fiber-type characteristics or energy-system time frames.
- Assuming diastolic blood pressure climbs during aerobic work.
- Treating rep-max conversions or HRmax estimates as precise individual values.
Rule of thumb
1 MET = 3.5 mL·kg⁻¹·min⁻¹, roughly resting oxygen uptake. To convert a measured VO₂ (mL·kg⁻¹·min⁻¹) to METs, divide by 3.5; a 21 mL·kg⁻¹·min⁻¹ workload equals 6 METs.