What is characterized by the shortening or shrinkage of muscles and tendons?

The correct answer is characterized by the shortening or shrinkage of muscles and tendons, which is known as contracture. Contracture occurs when there is a significant restriction in the range of motion of a joint due to the tightening of surrounding muscles, tendons, or both. This condition can arise from various causes, including prolonged immobility, nerve damage, or certain medical conditions that affect muscle or joint function.

Muscle hypertrophy involves the increase in muscle size due to strength training or resistance exercises, which is the opposite of what is described in the question. Atrophy refers to the wasting away or decrease in muscle size due to disuse or a lack of stimulation, leading to weaker muscles rather than their shortening. A spasm is a sudden, involuntary contraction of a muscle or group of muscles, which may lead to temporary tightness, but does not specifically imply a permanent shortening or shrinkage of tendons. Therefore, contracture is accurately defined by the characteristics mentioned in the question.