What is meant by "stress" in tissue properties?

• A. The internal reaction or resistance to an external load
• B. The elastic limit of tissue
• C. The extent of deformation caused by loading
• D. The outside force acting on tissue

Answer: (A)

"Stress" in tissue properties refers to the internal reaction that tissues exhibit in response to an external load. When an external force is applied to a material, the tissue generates an internal force that resists this application. This internal force is what is termed "stress," and it is typically measured as force per unit area. Understanding stress is critical in athletic training and rehabilitation because it helps practitioners assess how tissues will respond to physical activity, healing, and potential injury.

The other concepts mentioned, such as the elastic limit, the extent of deformation, and external forces, all relate to the broader topic of tissue mechanics but do not define stress itself. The elastic limit is related to the maximum stress a material can withstand before it deforms permanently, deformation pertains to the changes in shape or size of the tissue, and external forces are the stimuli that cause stress in the first place.