What is defined as an abnormal shortening of muscle tissue leading to resistance against passive stretch?

The correct answer is the term "contracture," which refers to an abnormal shortening of muscle tissue that results in increased resistance to passive stretching. This condition can lead to a decreased range of motion and may occur due to prolonged immobility, neurological conditions, or following injury. Contractures are often the result of changes in the muscle fibers and surrounding connective tissue, causing the muscle to maintain a shortened position.

Atrophy refers to the decrease in muscle size due to lack of use or disease, while hypertrophy would describe the increase in muscle size as a response to resistance training or regular exercise. Myositis is the inflammation of muscle tissue, which may lead to pain and weakness but does not specifically refer to abnormal shortening. Contracture is, therefore, the only option that succinctly captures the concept of shortened muscle tissue leading to resistance against passive stretch.