Constitution Attribute
Running is essential for every decent prisoner.
Constitution or body type defines everything connected with physical endurance and stamina. Is raised by: moving in general, walking, running, swimming, etc. Is lowered by: not moving, staying still for longer periods of time. It influences: health points, stamina, damage and status (shock, poison, etc.) resistances, immune system, calorie and water consumption efficiency. Ranges from 1 to 5.

Running Skill
Running is a skill that shows how athletic you are and how proficient you are at running. Is raised by: jogging or running. It influences: jogging and running speed.

Endurance Skill
Endurance is a skill that enables you to withstand pain by conserving strength and energy. Is raised by: moving under a weight load. It influences: stamina recovery rate, energy and water consumption rates.
Official SCUM in-game content (the game’s own text, translated by the studio).