Is lifting a glass of water to your mouth considered an isotonic muscle contraction? Is pushing against a stationary wall considered an isotonic muscle contraction?
Lifting a glass of water : Isotonic contraction
Pushing against stationary wall : Isometric Contraction
There are two types of muscle contraction : Isotonic & Isometric. When we lift a weight, muscles become shorter and thicker. In this type of contraction, tone or tensionof muscle remains the same and is referred to as isotonic contraction.
When we push against a wall the involved muscles remain at a constant length while the tone of the muscle increases. This type of contraction is known as isometric contraction.
From the picture we can see two types of contraction of muscle. As we move the glass it is isotonic contraction but we can not move the wall so the contraction is isometric :