Anatomy and physiology in physical activity
The anatomy and physiology domain examines how the skeletal, muscular, cardiovascular and respiratory systems produce and support movement. SEC questions often ask you to identify structures, explain their function during exercise and interpret simple physiological data.
Core structures and responses
- Joints: hinge (elbow, knee) allows flexion/extension; ball-and-socket (shoulder, hip) allows flexion, extension, abduction, adduction, rotation and circumduction. Ligaments join bone to bone; tendons join muscle to bone.
- Muscles: work in antagonistic pairs, e.g. biceps brachii flexes the elbow while triceps brachii extends it. Slow oxidative fibres suit endurance; fast glycolytic fibres suit brief, powerful efforts.
- Cardiovascular: cardiac output = stroke volume × heart rate. During exercise, stroke volume and heart rate rise, increasing oxygen delivery and removing CO2.
- Respiratory: inspiration is active at rest (diaphragm and external intercostals); expiration is passive at rest but active during intense exercise. Gaseous exchange occurs at alveoli by diffusion.
Worked example
A performer has a resting stroke volume of 70 mL and heart rate of 70 beats/min: cardiac output = 70 × 70 = 4,900 mL/min (4.9 L/min). During exercise, stroke volume is 110 mL and heart rate 160 beats/min: 110 × 160 = 17,600 mL/min (17.6 L/min). The reasoning is to multiply, keep units consistent and compare the rise.
Traps
Confusing tendons with ligaments; saying expiration is always passive; mixing up slow and fast fibres; forgetting that cardiac output increases mainly through heart rate at high intensities.