How Much Weight Really Goes Through the Leg in a Hydrotherapy Pool?
One of the most common questions we’re asked is:
“How much weight am I actually putting through my leg in the pool?”
The answer might surprise you… and its exactly why hydrotherapy is such a powerful rehabilitation tool.
At AquaPhysio, we don’t guess weight-bearing. We calculate it, using water depth, individual body factors, and tissue-healing requirements to guide safe, effective recovery. To demonstrate this, our Clinical Team Lead, Matt (5’10”), shows how different pool depths directly change how much load passes through the lower limbs, when we are stationary.
How Water Depth Changes Weight-Bearing When We Are Stationary
0% Weight-Bearing - Non-Weight Bearing
At deeper water levels where Matt cannot touch the pool floor, there is true non-weight bearing.
This stage is ideal in the early phases after surgery or fracture fixation, where joint compression must be minimised but movement is still essential. It allows patients to maintain mobility without stressing healing structures.
Common uses:
- Early post-operative rehabilitation
- Protected hip procedures
- Immediate post-fracture phases
15% Weight-Bearing - Upper Chest / Neck Depth
With the water level around 5 feet deep, submerging to the upper thoracic spine, only around 15% of body weight is transmitted through the legs. Research shows that immersion to C7 level in males can reduce weight-bearing to approximately 8-10%, making this an excellent option for very protected loading.
This depth allows:
- Gentle loading without overload
- Maintenance of muscle activation
30-35% Weight-Bearing-Mid-Chest Depth
At mid-chest (xiphisternum) level, the lower limbs typically bear around 30–35% of body weight when stationary.
This is a key transition phase where patients begin to:
- Tolerate more realistic loading
- Improve control and coordination
- Progress strength while protecting healing tissue
50-60% Weight-Bearing-Shallow Chest / Upper Abdomen
As the water becomes shallower, weight-bearing increases to around 50-60% of body weight.
This is where rehabilitation starts to closely resemble real-life movement, but still with:
- Reduced joint stress
- Improved movement quality
- Better tolerance compared to land-based rehab
All these values shown are intended as a static immersion baseline (quiet standing, bilateral support).
Once movement is introduced, effective loading at each depth can increase, often by 20-25% due to single leg support, changes in buoyancy assistance and altered vectors during gait like amount of sideways motion.
In practice we also take into account other individual factors, including their sex and body composition, which can subtly influence buoyancy and load transmission at a given immersion level.
Precision Weight-Bearing During Protected Healing
By simply adjusting water depth, we can precisely control how much load passes through the body. This allows rehabilitation to align closely with surgical protocols and fracture-healing requirements, rather than relying on time-based progression alone.
This means we can:
- Prescribe partial weight-bearing that matches post-operative guidance
- Maintain muscle strength and neuromuscular control during restricted phases
- Progress load based on height, sex, and tissue healing stage, not assumptions
Supporting Earlier, Safer Rehabilitation
This approach is particularly effective following:
- Hip arthroscopy
- Lower-limb fractures
- Achilles rupture
…and other injuries where load must be carefully managed.
Hydrotherapy allows patients to reduce deconditioning without compromising fixation, repair, or bone healing, supporting a smoother and safer return to function.
Weight-Bearing Is Calculated - Not Assumed
At Aqua Physio, every stage of rehabilitation is intentional.
Our multi-depth SwimEx® hydrotherapy pool enables precise, repeatable loading - giving clinicians control and patients confidence at every step of their recovery.