NETA Personal Trainer Practice Exam

Which type of exercise is characterized by no change in muscle length despite exerting force against resistance?

1. Isokinetic exercise

2. Isometric exercise

3. Open kinetic chain exercise

4. Eccentric exercise

The correct answer is: Isometric exercise

Isometric exercise is defined by the characteristic where muscle tension is generated without any change in the muscle's length, meaning the muscle contracts but does not shorten or lengthen. This type of exercise occurs when a muscle exerts force against a resistance while holding a stable position. Common examples of isometric exercises include planks, wall sits, and holding a weight in a static position. Because there is no movement at the joint during isometric contractions, the muscles work to maintain the position without changing length, which makes it particularly effective for maintaining strength and stability in specific postures. In contrast, the other types of exercises involve movement or varying muscle lengths. For example, isokinetic exercise involves movement at a constant speed regardless of the force applied, open kinetic chain exercise refers to movements where the distal segment (like a hand or foot) is free to move, and eccentric exercise focuses on the controlled lengthening of the muscle while it is under tension.