Types of skeletal muscle contraction

Types of skeletal muscle contraction

Skeletal muscle contraction is classified into two primary types based on how the muscle's length and tension change during the contraction:

• Isotonic contraction ("iso-" = same, "ton-" = weight/resistance/tension) — the muscle's length changes while its tension stays constant, so the force produced is unchanged throughout the movement. Lifting a dumbbell through a full range of motion, or general weightlifting, are everyday examples: the muscle visibly shortens as it moves the load.
• Isometric contraction ("iso-" = same, "metric-" = distance) — the muscle's length stays the same while its tension changes, so the force produced varies even though no visible movement occurs. Pushing against an immovable wall, or holding a heavy bag steady without moving it, are examples: the muscle is working hard and generating variable force, but it is not shortening. …