What type of muscle contraction occurs with no change in muscle length?

The type of muscle contraction that occurs with no change in muscle length is isometric contraction. During an isometric contraction, the muscle generates force without shortening or lengthening. This means that while the muscle is activated and producing tension, it does not move the joint or change its overall length. Isometric contractions are often utilized in various forms of strength training and rehabilitation activities where stabilization of the joint is necessary without movement.

For instance, when you push against an immovable object, the muscle fibers engage and tense up, but there is no visible change in the muscle length, illustrating the isometric nature of the contraction. This contrasts with other types of contractions like concentric, where the muscle shortens while producing force, or eccentric, where the muscle lengthens under tension. Isokinetic contractions, meanwhile, are characterized by a constant speed of contraction throughout the range of motion, which does not apply when discussing changes in muscle length specifically.