Which condition is a contributor to physical stress in diving?

Constricted movement is a significant contributor to physical stress in diving because it can limit a diver's ability to maneuver effectively underwater. When a diver's movement is restricted, whether due to ill-fitting gear, environmental factors, or physical constraints, it can lead to increased physical exertion. This added effort can elevate heart rates and fatigue levels, making it more challenging for divers to maintain control and perform necessary tasks, such as equalization, swimming, or executing specific dive techniques. Physical stress from constricted movement not only affects the diver's comfort but can also impact their ability to respond to emergencies, thus increasing the overall risk while diving.

In contrast, knowledge of diving techniques, a comfortable equipment fit, and proper hydration are essential for ensuring safety and minimizing stress, but they do not directly contribute to physical stress in the same way that constricted movement does.