Aquatherapy is any activity performed in water to assist in rehabilitation and recovery from hard training or serious injury.[1][2] 

Physical properties of water

In common with other forms of matter, water has certain physical properties which include mass, weight, density, relative density, buoyancy, Hydrostatic pressure, surface tension, refraction and reflection. [3][4]

Of the physical laws of water that the physiotherapist should understand and apply when giving Aquatherapy, those of buoyancy and hydrostatic pressure are the most important. The lateral pressure exerted and the effect of buoyance together will give the feeling of weightlessness.[3]

Buoyancy [5]

Buoyancy is the force experienced as an upthrust which acts in the opposite direction to the force of gravity. A body in water is therefore subjected to two opposing forces. When the weight of the floating body equals the weight of the liquid displaced, and the centres of buoyancy and gravity are in the same vertical line, the body is kept in stable equilibrium.[4] If the centres are not in the same vertical line the two forces acting on the body will cause it to roll over untill it reaches a position of stable equilibrium.

Hydrostatic pressure [5]

The molecules of a fluid thrust upon each part of the surface area of an immersed body. Pascal's law states that fluid pressure is exerted equally on all surface areas of an immersed body at rest at a given depth. Pressure increased with the density of the fluid and with its dept. This means that swelling will be reduced more easily if exercises are given well below the surface of the water where the increased pressure may be used.[4]

Physiological effects

The physiological effects of water therapy combine those brought by the hot water of the pool with those of the exercises. The exent of the effects varies with the temperature of the water, the lenght of the treatment and the type and severity of the exercise.[3]

The physiological effects of exercise in water are similar to those of exercise on dry land. The blood supply to the working muscles is increased, heat is evolved with each chemical change occurring during the contraction, and the muscles temperature rises. There is an increased metabolism in the muscles resulting in a greater demand for oxygen and increased production of carbon dioxide. These changes augment the similar changes brought about by the heat of the water, and both contribute towards the final effect. The range of joint movement is either maintained or increased, and muscle power increases.[4]

During the immersion the physiological effects are similare to those brought about by any other form of heat but less localized. A rise in body temperature is inevitable because the body gains heat from the water and from all the contracting muscles performing the exercises. As the skin becomes heated the superficial blood vessels dilate and the peripheral blood supply is increased. The blood flowing through these vessels is heated and by convection, the temperature of the underlying structures rises.[4]

The relatively mild heat of the water reduces the sensitivity of sensory nerve endings and the muscle tone will diminish when the muscles are warmed by the blood passing through them.[4]

Therapeutic effects 

  • Relieve pain and muscle spasm[4]
  • To gain relaxation [4]
  • To maintain or increase the range of joint movement[3]
  • To re-educate paralyzed muscles[3]
  • To strengthen weak muscles and to develop their power and endurance.[4]
  • To encourage walking and other functional and recreational activities.[3]
  • To improve circulation ( throphic condition of the skin ) [4]
  • To give the patient encouragement and confidence in carrying out his exercises, thereby improving his morale.[4]

Clinical Contraindications [4][2]

Serious Contraindications Absolute Contraindications
  • Cardiovascular disease
  • cardiopulmonary disease
  • Diabetic
  • Balance disorder
  • History of CVA, Epilepsy
  • Incontinence
  • Labyrinthitis
  • a cold
  • Influenza
  • Fever
  • skin conditions
  • Chemical allergies (Chlorine)
  • Contagious diseases
  • Hepatitis
  • Tracheotomy
  • Urinary tract infection
  • Serious Epilepsy
  • Urinary incontinence
  • Open Wounds 
  • Recently Surgery 
  • Hydrophoby

Prevention and Risk Management 

An accident is always possible when a patient undergoes physiotherapy in any form, but such mishaps can be avoided if the physiotherapist is aware of the possible causes of accidents and takes sufficient care to ensure that they do not happen.[4] For dangers and precautions see Hydrotherapy Risk Management.

Alternative methods [4]

The "Watsu Method"

Also called “water Shiatsu", is a combination of Aquatherapy and Shiatsu. Watsu is based on stretching the body in the supportive, relaxing medium of warm water. Beside the physical aspect, also the mental aspect has a great importance during this therapy. The Watsu method has a general relaxation and calming effect that soothes the muscle tension and stimulates all of the body systems and organs by nourishing the energy flow.[4]

The "Bad Ragaz Ring Method"

The "Halliwick Method"

The "Burdenko Method"

The "Feldenkrais Method"


  1. Bartels et al., Aquatic exercise for the treatment of knee and hip osteoarthritis (Review),The Cochrane Library 2007, Issue 4 (Level of evidence : 1A)
  2. 2.0 2.1 Lori T. Brody, Paula R. Geigle (2009) Aquatic Exercise for Rehabilitation and Training. United states of America: Human Kinetics.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 Duffield M.H (1969) Exercise in water. Baltimore: The Williams & Wilkins Company.
  4. 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 4.14 Meeusen R. (2003) Sportrevalidatie: Aquatherapie (deel 1). België: Kluwer
  5. 5.0 5.1 Joanne M. Koury. (1996) Aquatic therapy programming: Guidelines for orthopedic rehabilitation. United stats of America: Human Kinetics.