What involves the external application of water in massage therapy?

The chosen answer is hydrotherapy, which specifically involves the use of water for therapeutic purposes. In the context of massage therapy, hydrotherapy can include various techniques such as soaking, applying wet packs, or using water jets to improve circulation, relieve pain, and enhance relaxation. The external application of water can take many forms, including baths, pools, or even localized applications like compresses. The therapeutic effects of hydrotherapy stem from the properties of water, such as temperature regulation and buoyancy, which can provide significant physical and psychological benefits.

Thermal therapy, while related, broadly addresses the use of heat and cold for therapeutic purposes, which can include but is not limited to water. Scalp massage specifically targets the head and does not focus on water applications. Acupressure is a technique that involves applying pressure to specific points on the body to promote healing, and is not associated with water use.