Which of the following are the three types of muscle contractions?

The three types of muscle contractions are concentric, eccentric, and isometric.

Concentric contractions occur when a muscle shortens while generating force, such as when lifting a weight. This type of contraction is important for overcoming resistance and is commonly seen during activities like bicep curls.

Eccentric contractions involve the lengthening of a muscle while it is still under tension, which usually occurs when lowering a weight or during controlled movements. This type of contraction is significant for muscle control and stability in activities such as descending stairs.

Isometric contractions happen when a muscle generates force without changing length, such as holding a weight steady in a fixed position. This type of contraction is crucial for maintaining posture and stabilizing joints.

Understanding these types of muscle contractions is fundamental in kinesiology, as they play distinct roles in movement, strength training, and rehabilitation. The other provided choices refer to different concepts, such as specific motions (flexion, extension) or classifications of muscle roles (agonist, antagonist), rather than types of contractions themselves.