Which concept explains that ROM varies between individuals based on the series of joints involved and the functional demands placed on the person?

• A. Normal ROM
• B. Individual variation
• C. Scarring
• D. Arthritis

Answer: (B)

ROM varies among individuals because the movement depends on which joints are in the kinetic chain and the functional demands placed on the body. Different people use their joints in different ways, and tissues adapt to those demands over time. When a joint and its neighboring joints are regularly moved through a wide range as part of daily activities or sport, the surrounding muscles, ligaments, and connective tissue can lengthen and become more flexible, while limited use or specific task patterns can lead to tighter tissues and a reduced range. This natural difference from person to person is called individual variation. The other options describe broader or specific conditions that can limit ROM (like scarring or arthritis) or refer to a population reference, but they don’t capture the idea that ROM differences arise from the particular joints involved and the functional demands on each person.