Jeffery Allen PT. OCS
Aquatic Therapy for the Low Back Pain Patient
offers a therapeutic environment which is unachievable on land.
Application of weight bearing in graded or progressive manner
Exercise in water produces less
spinal and lower extremity joint compression than the identical exercise
performed on land. This reduction in compression creates an environment in
which weight bearing and joint compression (of the lower extremities and
spine) can be applied in a graded or progressive manner by the therapist.
Archimedes' principle states:
"when a body is wholly or partially immersed in a fluid, it
experiences an upthrust equal to the weight of fluid displaced."
This upthrust, or buoyancy, counterbalances gravity and supports the body,
resulting in an apparent reduction in weight bearing through the spine and
lower extremities. Buoyancy can provide either assistance and support
or resistance to movement of the body in the water, depending on the
position of the individual. Weight bearing may be systematically
reduced by increasing the amount of the body submerged.[8,9]
study by Harrison and Bulstrode measured static weight bearing in a pool
using a population of healthy adults. Results indicated that weight
bearing during immersion was reduced to less than land-based weight.
Immersion to C-7 levels reduced weight to 5.9%-10% of normal weight.
Immersion to the xiphosternum reduced weight to 25%-37% of normal.
Immersion to the level of the anterior superior iliac spine (ASIS) reduced
weight to 40%-56% of normal.
follow-up study by Harrison, Hillma, and Bulstrode compared weight bearing
during immersed standing, slow and fast walking. During slow walking,
subjects had to be immersed to the ASIS before weight bearing was reduced
to 75% of normal. Immersion to the clavicle during slow walking reduced
weight bearing up to 50% of normal values, and immersion above the
clavicle resulted in weight bearing 25% of normal or less.
fast walking, mid-trunk immersion produced weight-bearing up to 75% of
actual weight. Subjects had to be immersed deeper than the xiphosternum in
order for weight bearing to be less than 50% and deeper than C-7 for
weight bearing to be less than 25% of normal values.
Decrease in subjective complaints
Aquatic therapy performed in a therapeutic pool provides a palliative
effect and may reduce these complaints. Argument : Although dependent on
the population using the facility, therapeutic pools are generally heated
to between 92 and 97 degrees Fahrenheit.
temperatures above "thermoneutral" (approximately 93-95 degrees
F at rest and 91-92 degrees F during mild exercise),[11,12] body
temperature increases due to the reduced ability of the body to dissipate
heat through the skin.[13,14] Thermal energy (heat) is exchanged between
water and the body and between air and the body.
exchange between a submerged body and the water occurs through both
convection and conduction. Thermal energy is also exchanged between the
body and the air through radiation and evaporation — methods which
become more critical if the total body is immersed and the water
temperature prevents heat dissipation from occurring during aquatic
in water warmer than the skin will result in a rise in superficial tissue
temperature which creates a palliative effect like that experienced during
the therapeutic use of paraffin, Fluidotherapy® and moist heat.
mechanism of pain relief may come from one of several phenomena discussed
in great detail in the July, 1997 issue of the Journal of Aquatic Physical
Movement-induced enhancement of somatosensory input (improved
Movement of a body part through water results in greater somatosensory
input to receptors than movement of that body part through air. Argument :
Movement through water is affected by turbulence and viscosity. Water
is more viscous than air, and resistance to flow through water is greater
than resistance to flow through air. Thus, it takes more force to push
through water molecules than to push through air molecules. Additionally,
the faster an object is pushed through the water, the more turbulence is
created and this creates additional resistance to movement.
Geigle and colleagues argue that somatosensory input is increased more by
moving an object through a viscous liquid than by moving through a less
viscous gas (air). They postulate that resistance to movement may
"cause distention or stretch of the skin resulting in stimulation of
rapidly adapting mechanoreceptors, perhaps contributing to better
Interruption of pain cycle
Standing in water results in less
spinal and lower extremity weight bearing than standing on land. This
reduction in weight bearing results in a reduction in motor activity
required from postural muscles. This reduction in motor activity allows
patients to maintain an upright, stable position with less muscle spasm.
Archimedes' principle states: "when a body is wholly or partially
immersed in a fluid, it experiences an upthrust equal to the weight of
fluid displaced." Water has a relative density (specific gravity)
equal to 1. It serves as the reference point for all objects. Objects with
specific gravity less than water float, and those with specific gravity
greater than water sink. Objects with specific gravity near the value of
water hover just below the surface. The human body has elements which tend
to sink (dense muscle) and elements which tend to float (fatty tissue and
air-filled lungs). This tendency to float counterbalances gravity and
supports the body, resulting in an apparent reduction in weight.
reduction in weight can provide relief from compressive forces on painful
joints. It is therefore possible for a person to stand, even walk, with
reduced pain without external support or abnormal protective mechanisms in
the water. Thus, the patient can initiate "normal" weight
bearing tasks such as gait, transfers, and balance drills in the water and
offset any deconditioning effects of immobility or reduced movement.
activity may be systematically reduced by increasing the amount of the
body submerged. Mano et al examined the effects of graded immersion on
skin and muscle receptors during quiet standing. Mano and his team
examined the effects of immersion in warm water on muscle sympathetic
activity (MSA) and electromyography (EMG) of the soleus muscle, and skin
sympathetic activity (SSA) of the sole of the foot. As the level of
immersion increased, both MSA and EMG activity decreased proportionally as
weight bearing diminished. With immersion to the cervical spine, both MSA
and EMG became almost absent. In other words, the subjects' calf muscles
became less active in a buoyant environment. In effect, the calf muscle
responsible for maintaining upright posture in a gravity-based environment
had diminished responsibilities.
as the level of immersion was increased, the sympathetic activity of the
skin on the sole of the foot decreased. With immersion to the cervical
spine, the SSA showed a marked and proportional decrease in activity.
Translated, this means that although immersion results in less motor
activity for postural muscles such as the calf, it also results in less
sensory input to the skin (and probably joint) receptors which record
4. Has the evidence (scientific research) demonstrated benefits with
aquatic physical therapy for this type of patient?
American Physical Therapy Association. The Guide to Physical Therapy
Practice: Part II: Preferred Practice Patterns. Phys Ther
American Physical Therapy Association (APTA) Aquatic Physical Therapy
Section. Statement of Purposes, Rationale, and Goals Alexandria, VA: APTA;
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Practice: Part I: Description of Patient/Cleint Management. Phys Ther
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Thacker JG. Bioengineering principles of hydrotherapy. J Burn Care Rehabil
Cirullo JA. Aquatic physical therapy approaches for the spine. Orthop Phys
Ther Clin North Am 1994;3(2):179-208.
Styer-Acevedo J, Cirullo JA. Integrating land and aquatic approaches with
a functional emphasis. Orthop Phys Ther Clin North Am 1994;3(2):165-178.
Harrison RA, Bulstrode S. Percentage weight bearing during partial
immersion in the hydrotherapy pool. Physiother Practice 1987;3:60-63.
Harrison RA, Hillma M, Bulstrode S. Loading of the lower limb when walking
partially immersed: implications for clinical practice. Physiotherapy
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Ptacin MJ, Sobocinski KA, Morris RD. Cardiovascular regulation during
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Sagawa S, Shiraki K, Yousef MK, Konda N. Water temperature and intensity
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Walsh M. Hydrotherapy: the use of water as a therapeutic agent. In:
Michlovits SL, Wolf S (eds). Thermal Agents in Rehabilitation.
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Richley Geigle P, Cheek WL, Gould ML, Hunt HC III, Shafiq B. Aquatic
physical therapy for balance: the interaction of somatosensory and
hydrodynamic principles. J Aquatic Phys Ther 1997;5(1):4-10.
Mano T, Iwase S, Yamazaki Y, Saito M. Sympathetic nervous adjustments in
man to simulated weightlessness induced by water immersion. Sangyo Ika
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Allen Physical Therapy