Which modality involves immersion in a bath of water for therapeutic purposes?

• A. Diathermy
• B. Ultraviolet
• C. Whirlpool
• D. Infrared

Answer: (C)

Immersion in a bath of water for therapeutic purposes is hydrotherapy. A whirlpool is a specific hydrotherapy modality that involves soaking in water while jets create movement and massage. This combination of water immersion, temperature effects, and mechanical agitation helps relax muscles, improve circulation, reduce edema, and decrease joint loading, which is why it best fits the description of therapeutic immersion in water. The other options are heating or light therapies not involving water: diathermy uses electrical currents to heat tissue, ultraviolet uses UV light, and infrared uses radiant heat—none require immersion.