When Does Isotonic Contraction Occur?

Isotonic contractions maintain constant tension in the muscle as the muscle changes length. This can occur only when a muscle's maximal force of contraction exceeds the total load on the muscle. Isotonic muscle contractions can be either concentric (muscle shortens) or eccentric (muscle lengthens).

What causes an isotonic contraction?

Contractions that involve shortening of the muscle are referred to as isotonic or concentric contractions. This type of contraction occurs when the force generated by the muscle is greater than the constant load acting on the muscle.

Where does isometric contraction occur?

Isometric contraction occurs when muscle length remains relatively constant as tension is produced. For example, during a biceps curl, holding the dumbbell in a constant/static position rather than actively raising or lowering it is an example of isometric contraction.