Active versus Passive Aquatic Therapy: Understanding the Difference and the Healing Potential of WATSU®

Water has been recognised as a source of healing and renewal for centuries. In modern healthcare and rehabilitation, aquatic therapy or hydrotherapy has become an established tool to help people improve mobility, reduce pain, and restore wellbeing. Within aquatic therapy, two broad approaches are commonly used: active and passive therapy.

While active aquatic therapy involves exercises performed by the client, passive therapy focuses on relaxation and therapist-led movement, often in warm water. Among the passive approaches, WATSU® stands out as a unique form of aquatic bodywork that supports both physical and emotional healing.

Defining Active vs. Passive Aquatic Therapy

Active Aquatic Therapy

• In active aquatic therapy, the client participates directly, performing specific movements or exercises guided by a therapist.

• The buoyancy, hydrostatic pressure, and resistance of water allow for safer and more effective rehabilitation—reducing joint load, enabling earlier muscle re-education, and improving strength, coordination, and balance.

• Active aquatic therapy is often used in recovery from injury or surgery, for mobility training, or to maintain fitness in people with chronic conditions.

Passive Aquatic Therapy

• Passive therapy, by contrast, requires little or no active effort from the client. Instead, the therapist supports and gently moves the client in the water.

• The focus is on relaxation, pain relief, and nervous system regulation.

• Passive approaches may include immersion baths, whirlpools, or manual techniques like aquatic bodywork.

Comparing Active and Passive Approaches

Feature	Active Aquatic Therapy	Passive Aquatic Therapy
Patient Role	Performs exercises with therapist guidance	Fully supported, therapist moves the body
Primary Goals	Strength, mobility, balance, endurance	Relaxation, pain relief, nervous system reset
Typical Uses	Rehabilitation after injury/surgery, arthritis, neurological training	Chronic pain, stress, limited mobility, trauma support
Water Properties	Buoyancy reduces load, resistance builds strength	Warmth and support induce relaxation, reduce spasm

Both approaches are valuable—and in many treatment programs, therapists may combine elements of each depending on the client’s needs.

Spotlight on Passive Aquatic Bodywork: WATSU®

Among passive aquatic therapies, WATSU® is one of the most well known. Developed in the early 1980s by Harold Dull, WATSU® combines principles of Shiatsu massage, gentle stretching, joint mobilisation, and mindful presence, all while floating in warm water.

A therapist gently cradles, rocks, and moves the client through flowing patterns, allowing the body to release deeply held tension. Sessions take place in water heated to body temperature (~35 °C), which enhances comfort and relaxation.

While WATSU® can be beneficial for anyone as well as serve as deeply calming and restoring experience (like massage) for an improved sense of wellbeing. it has also been shown to offer benefits for clients in clinical settings for some specific conditions:

Clinical Benefits of WATSU®

WATSU® produces measurable physiological effects by shifting the body from a “fight-or-flight” (sympathetic) state into a “rest-and-digest” (parasympathetic) mode. Documented changes include:

• Decreased heart rate

• Slower, deeper breathing

• Increased peripheral circulation

• Reduced muscle spasm, rigidity, and spasticity

• Enhanced digestion and immune function

These changes directly benefit clients with orthopaedic, neurologic, and rheumatologic conditions.

Benefits for Special Needs and Chronic Conditions

Orthopaedic & Rheumatologic Benefits

• Relief from joint compression and stiffness

• Increased range of motion through gentle, unloaded stretching

• Soft tissue release and reduced muscle guarding

• Significant pain reduction—both physical and emotional

  
  

Neurologic Benefits

• Reduction of spasticity and abnormal muscle tone

• Gentle rocking and trunk rotation help decrease hypertonicity

• Improved movement for clients with stroke, cerebral palsy, Parkinson’s disease, or spinal cord injury

  
  

Benefits often reported include:

• Increased mobility

• Muscle relaxation

• Decreased spasm and pain

• Improved sleep and digestion

• Enhanced immune system response

• Greater reduction of chronic pain

• Decreased anxiety and emotional distress

WATSU® is now incorporated into aquatic therapy programs in hospitals, rehabilitation centres, and clinics worldwide, supporting clients with traumatic brain injury, fibromyalgia, ankylosing spondylitis, post-surgical recovery, PTSD, and more.

Many clients have report that “nothing else is as effective in decreasing their pain and improving their ability to move.”

Choosing the Right Approach

• Active aquatic therapy is best suited for rehabilitation goals requiring muscle engagement, strength, and balance training.

• Passive approaches like WATSU® are ideal when clients need profound relaxation, pain management, emotional support, or when active participation is not possible.

Often, the most effective programs combine both, tailoring sessions to each individual’s condition, goals, and stage of recovery.

Conclusion

Active and passive aquatic therapies are not opposites, but complementary tools in water-based rehabilitation and wellness. Active therapies restore function and strength; passive therapies like WATSU® nurture the nervous system, reduce pain, and unlock deeper levels of healing.

Whether you are a therapist seeking to expand your practice, or someone looking for relief and renewal, exploring both approaches may open new possibilities for movement, comfort, and wellbeing—supported by the gentle power of warm water.