Week 5: Introduction to Muscle Structure and Function

This week introduces skeletal muscle structure and function from the cellular scale (cross-bridge cycle, calcium cycling, fiber types) up to the tissue scale (force-length and force-velocity properties, power, efficiency).

Lectures

• Lecture 11: Introduction to Muscle Structure and Function 1 — Cellular Scale (28 slides) Skeletal muscle terminology and ultrastructure, the cross-bridge cycle, calcium cycling and the activation-relaxation cycle, twitch kinetics, the zero-sum game of muscle volume fractions, fiber-type categories, training-induced mitochondrial changes.

• Lecture 12: Introduction to Muscle Structure and Function 2 — Tissue Scale (32 slides) Hypertrophy, hummingbird flight muscle, regional endothermy and heater organs, types of muscle contraction, isometric force-length and isotonic force-velocity relationships, the 3D force-length-velocity surface, activation scaling, and the optimal velocity for peak power.

• Week 5 Friday Review and Discussion (12 slides) Satellite cells and “muscle memory”, sarcopenia and hybrid fiber types, endurance vs resistance training in seniors, muscle quantity vs quality, the high-heels study, and two practice activities (power-velocity construction and inferring muscle function from a pie chart).