Aquatic Therapy for Knee Osteoarthritis

Knee osteoarthritis is one of the most common causes of chronic joint pain and mobility limitations in older adults. A 2025 narrative review highlights the growing evidence that aquatic therapy for knee osteoarthritis is a safe and effective rehabilitation approach that reduces pain while improving functional mobility, muscle strength and balance.

The review analysed recent randomized controlled trials and systematic reviews, demonstrating that water-based exercise consistently provides meaningful clinical benefits for people living with knee osteoarthritis.

Why aquatic therapy is effective for knee osteoarthritis

People with knee osteoarthritis often experience pain during walking, standing and exercise. These symptoms can make conventional land-based rehabilitation difficult and reduce long-term adherence to exercise programmes.

Aquatic therapy provides a supportive environment where the physical properties of water reduce stress on the joints while allowing patients to perform strengthening and mobility exercises with greater comfort and confidence.

According to the review, aquatic therapy is particularly valuable because it combines pain relief with improvements in functional performance.

Key benefits of aquatic therapy

The reviewed studies consistently demonstrated positive clinical outcomes for patients with knee osteoarthritis.

Significant pain relief

Pain reduction was one of the most consistent findings across the reviewed studies. Water-based exercise reduced joint discomfort, allowing patients to participate more comfortably in rehabilitation and daily activities.

Several studies also reported greater pain relief than comparable land-based exercise programmes.

Improved functional mobility

Aquatic therapy significantly improved functional mobility, including walking ability, sit-to-stand performance and overall daily function.

These improvements help patients maintain independence and participate more easily in everyday activities.

Increased muscle strength

Water resistance provides gentle but effective strengthening throughout every movement.

Multiple studies reported improvements in knee extensor and flexor strength, contributing to better joint stability and reduced fatigue.

Better balance and postural control

Several studies demonstrated improved balance, posture and movement control following aquatic therapy.

Better balance may reduce the risk of falls, particularly in older adults with knee osteoarthritis.

Higher patient adherence

One of the most important findings was that patients were more likely to complete aquatic rehabilitation programmes than traditional land-based exercise.

Reduced pain during exercise and greater enjoyment contributed to higher attendance and treatment adherence.

Different types of aquatic therapy

The review describes several aquatic rehabilitation approaches that have shown positive clinical outcomes.

Hydrotherapy

Traditional hydrotherapy programmes using therapeutic exercises in heated pools consistently reduced pain while improving physical function and muscle strength.

Aquatic cycling

Aquatic cycling was shown to improve knee pain, physical function and cardiovascular fitness while maintaining excellent patient adherence.

This approach may be particularly suitable for individuals with mild to moderate knee osteoarthritis.

Whole-body aquatic exercise

Studies that combined lower limb exercises with trunk and upper body training demonstrated greater improvements in balance, function and pain than lower limb exercises alone.

Why exercising in water works

The therapeutic effects of aquatic therapy are largely explained by the unique physical properties of water.

Buoyancy reduces joint loading

Water supports body weight, decreasing compressive forces acting on the knee joint and allowing painful movements to be performed more comfortably.

Hydrostatic pressure supports movement

Hydrostatic pressure improves circulation while providing gentle support around the joints, helping patients move with greater confidence.

Water resistance strengthens muscles

Unlike traditional weights, water provides continuous resistance in every direction, allowing muscles to strengthen while minimising impact on the joints.

Who benefits most from aquatic therapy?

The review suggests that aquatic therapy is particularly beneficial for:

• Older adults with knee osteoarthritis
• Individuals with obesity
• Patients with reduced mobility
• People unable to tolerate land-based exercise
• Individuals experiencing chronic knee pain during walking or exercise

For these populations, aquatic therapy provides a comfortable and accessible rehabilitation environment that encourages regular participation.

Clinical implications

The authors conclude that aquatic therapy should be actively considered as part of comprehensive rehabilitation programmes for knee osteoarthritis.

Beyond reducing pain and improving mobility, aquatic therapy offers excellent patient satisfaction, strong safety outcomes and high treatment adherence, making it a valuable addition to conservative osteoarthritis management.

Conclusion

Current evidence consistently supports aquatic therapy for knee osteoarthritis as a safe, low-impact and effective rehabilitation intervention.

By reducing pain, improving mobility, increasing muscle strength and enhancing balance, aquatic therapy helps patients remain active while improving their overall quality of life.

The review recommends further research into long-term outcomes and standardised treatment protocols, but the existing evidence strongly supports incorporating aquatic therapy into modern knee osteoarthritis rehabilitation.