Hydrotherapy 1st Lecture PDF

Hydrotherapy Dr. Basma Ibrahim, MSc, PhD Cairo university Lecturer in Egyptian Chinese University  Hydrotherapy Definition Hydrotherapy, or water therapy, is the use of water (hot, cold, steam, or ice) to relieve discomfort, promote physical well-being, to...

Hydrotherapy Dr. Basma Ibrahim, MSc, PhD Cairo university Lecturer in Egyptian Chinese University  Hydrotherapy Definition Hydrotherapy, or water therapy, is the use of water (hot, cold, steam, or ice) to relieve discomfort, promote physical well-being, to facilitate healing and exercise and to enable patients to achieve therapy goals.  General concept of Hydrotherapy The properties of water provide treatment options that might otherwise be difficult or impossible to Movement and exercise of the upper provide with land-based and lower extremities can be interventions. For example, in a pool, facilitated in these positions by the a patient can be placed in non-weight- effects of buoyancy. bearing positions (supine, prone, or sitting) with the use of buoyant devices.  Today the use of Historically, hydrotherapy whirlpools, particularly Water in the pool can was delivered in metal for treating wounds, serve as resistance to tubs of water agitated by has decreased because exercise to facilitate an attached electric motor of infection concerns muscle strengthening. (commonly known as and the resources and whirlpools) or by expense required for immersion in larger pools their use. of water (e.g., swimming pools). Newer techniques that deliver a pressurized Pool therapy, or aquatic Other methods of stream of water to therapy, has become hydrotherapy, such as wounds and incorporate increasingly popular in contrast baths, have suction, such as pulsed rehabilitation limited support in the lavage with suction programs. research literature for (PLWS) devices, have effectiveness mostly replaced whirlpools for wound care. The physiological effects of hydrotherapy primarily depend upon; And whether the How much of the The temperature of person or body body is immersed the water, part in the water is in the water, at rest or moving. Physical Properties Of Water Physical Properties Of Water 1. Buoyancy 2. Viscosity 3. Hydrostatic pressure 4. Hydrodynamics 5. Thermodynamics 1. Buoyancy  1. Buoyancy Content Definition Archimedes’ principle Introduction Table of percentage of weight bearing when immersed in water Types of exercise used buoyancy Difference between center of gravity and center of buoyancy  Definition the tendency of a body to float or to rise when partially or fully immersed in water or fluid. Archimedes’ principle: states that “the buoyant force on a body immersed in a fluid is equal to the weight of the fluid displaced by that object. One of the most important properties of water is buoyancy. A body or body part immersed in water will experience this buoyant force, which reduces the force of gravity on the body and, thus, decreases weight-bearing on the lower part of the body. A person immersed in water up to the neck will have about 10% of the body weight bearing on the lower body. Immersion up to the xiphoid process will bear about 33% body weight on the lower body. And immersion up to the anterior superior iliac spines will bear about 50% body weight on the lower extremities, and here is in detail the percentage of weight bearing when female and male immersed in water.  Table shows percentage weight bearing when immersed in water Level Female Male C7 10% 11.8% Xiphisternum 31% 35% A.S.I.S 52% 59% Exercise of the extremities can be assisted by buoyancy. A person standing in water up to the neck can raise an extremity with the assistance of buoyancy. Resistance exercises for strengthening can be performed against the force of buoyancy when an extremity moving downward against the force of buoyancy For example, A patient recovering from surgical repair of the rotator cuff muscles can use the buoyant force of water to assist in raising the extremity from the side of the body to 90° of flexion or abduction while standing in neck-deep water. When returning the extremity to the side, buoyancy can be used as A resistance to this movement. When a body is partially immersed in water, it is subjected to two opposing forces: buoyancy and gravity. The reference point for analyzing the effects of gravity on the body is the center of gravity, whereas the reference point for analyzing the effects of buoyancy of the part of the body that is immersed in water is the center of buoyancy. The body will remain balanced, and no movement will take place if these forces are equal and opposite to each other. When these forces are unequal and unaligned, the body or body part will tend to move or rotate. This motion may cause a person standing or sitting in a pool of water to become unstable and potentially unbalanced. Therapists must be aware of the combined effects of gravity and buoyancy of a person immersed in water and use appropriate guarding and/or flotation devices to prevent loss of balance.  It is defined as the ratio of the object’s density to that of standard density like water. So, it is the ratio of the object’s density to the water’s density at 39.2°F (4°C) Specific The specific gravity value assigned to Gravity water is 1, whereas the specific gravity of the body with air in the lungs is 0.963. Objects with a specific gravity less than 1 will displace a proportional amount of water and will float.  The buoyancy of an object in water depends on its density (mass per unit volume). Objects that are Specific denser than water will have less Gravity buoyancy and will tend to sink. Objects that are less dense than water will experience more buoyancy and will tend to float.  The body will displace about Buoyancy of the body will 90% of water when immersed be affected by the amount and about 2.6% will float. This of air in the lungs. Fully enables a person lying supine inflated lungs will increase in water to keep the face out of buoyancy, and deflated the water while most of the lungs will decrease body is immersed slightly buoyancy. below the surface.  Buoyancy is also dependent upon body composition. Obese individuals will have increased buoyancy because fat tissue has a lower specific gravity than most other tissues. Females have greater buoyancy than males because females have a higher body fat percentage. This provides an advantage for females for swimming, resulting in an approximate 30% lower energy expenditure than males. 2. VISCOSITY  Viscosity content Definition Introduction Types of resistive Cohesive Bow force Drag force forces: force  Definition of viscosity Is the internal friction present in liquids secondary to the cohesive forces between the molecules.  Introduction If a patient experiences When an arm or a leg is pain during exercise and moved through water, the stops pushing against the water’s viscosity will resist this water, the force of the movement. The faster the limb water against the body part is moved, the greater the drops instantly. This can resistance encountered serve as a protective effect secondary to water viscosity. during exercise in water. Types of resistive forces: A) Cohesive force C)Drag B) Bow force force  Cohesive Force There is a slight but easily overcome cohesive force that runs in a parallel direction to the water surface. This resistance is formed by the water molecules loosely binding together, creating a surface tension. Surface tension can be seen in still water because the water remains motionless with the cohesive force intact unless disturbed  Bow Force A second force is the bow force, or the force that is generated at the front of the object during movement. When the object moves, the bow force causes an increase in the water pressure at the front of the object and a decrease in the water pressure at the rear of the object. This pressure change causes a movement of water from the high-pressure area at the front to the low-pressure area behind the object. As the water enters the low-pressure area, it swirls-in to the low-pressure zone and forms eddies, or small whirlpool turbulences. These eddies impede flow by creating a backward force, or drag force Drag force Drag force is a force that resists the movement of an object or body part in water, and it is parallel to the direction of movement but in the opposite direction.  Doubling the velocity of movement of an object or body part in water will quadruple the magnitude of the drag force. If the object or body part moves downward in the water, then the resistance encountered is the sum of both the drag force and the buoyancy.  This third force, the fluid drag force, is very important in aquatic therapy. The bow force on an object (and, therefore, also the drag force) can be controlled by changing the shape of the object or the speed of its movement  Frictional resistance can be decreased by making the object more streamlined. This change minimizes the surface area at the front of the object. Less surface area causes less bow force and less of a change in pressure between the front and rear of the object, resulting in less drag force. In a streamlined flow, the resistance is proportional to the velocity of the object. When working with a patient with generalized weakness, consideration of the aquatic environment is necessary. Increased activity occurring around the patient and turbulence of the water can make walking a challenging activity On the other hand, if the object is not streamlined, a turbulent situation (also referred to as pressure or form drag) exists. In a turbulent situation, drag is a function of the velocity squared. Thus, by increasing the speed of movement 2 times, the resistance the object must overcome is increased 4 times. This provides a method to increase resistance progressively during aquatic rehabilitation. Considerable turbulence can be generated when the speed of movement is increased, causing muscles to work harder to keep the movement going. Another method to increase resistance is to change directions of movement, creating increased drag. Finally, by simply changing the shape of a limb through the addition of rehabilitation equipment that increases surface area, the athletic trainer can modify the patient’s workout intensity to match strength increases  Precaution for drag forces Drag forces must be considered carefully when attempting to protect a limb during rehabilitation. Drag forces can  torque over any joint in rehabilitation which may be contraindicated. 3. Hydrostatic Pressure Hydrostatic pressure content Definition Introduction Advantages and disadvantages  Hydrostatic pressure is the force that water Definition exerts on the immersed body or body part in rest.  Introduction This force impacts the body equally from all directions at a given depth of immersion. The amount of hydrostatic pressure will vary, depending on the depth of immersion of the body part. A person standing in a pool of water up to the neck will have a greater amount of hydrostatic pressure against the feet than against the trunk or shoulders. Therefore, when exercising near the water’s surface, the patient will encounter less resistance than when exercising at a greater depth.  Advantages and disadvantages This increased pressure may encourage venous return in a proximal direction from the lower extremities. Using therapeutic effect of aquatic therapy, combined with the effect of hydrostatic pressure, for increasing lymph flow and reducing edema in patients with lymphedema. However, the dependent position of the body part may cancel this effect. Some studies found that the combination of heat and the dependent position of an extremity in a whirlpool have the potential to encourage lower extremity swelling. 4. Hydrodynamics  Hydrodynamics content Difference between hydrodynamic Types of Definition Introduction pressure and hydrodynamics hydrostatic pressure Definition branch of physics that deals with the motion of fluids and the forces acting on solid bodies immersed in fluids and in motion relative to them Difference between hydrodynamic pressure and hydrostatic pressure Hydrostatic pressure is the pressure exerted by, or existing within, a liquid at rest with respect to adjacent bodies, while hydrodynamic pressure is the pressure generated by the motion of a liquid relative to adjacent bodies.  Types of hydrodynamics Streamline flow Turbulent flow Streamline flow (or laminar flow): This occurs when each molecule of the fluid follows parallel to each other in a smooth path without crossover of paths, typically in slow movement. Turbulent flow: is the flow of fluids in erratic, small, whirlpool-like circles called eddy currents or eddies, typically in fast movement. Viscosity of water is much greater during turbulent water flow, resulting in more resistance to movement. Movement of a body part in water at rest will encounter minimal turbulence, although the movement itself will create some turbulence. Movement against turbulent water will encounter more resistance, as experienced while moving a body part in a whirlpool when the water is agitated. 5. Thermodynamics  Thermodynamics content Specific heat: Heat transfer: - Definition Definition - Introduction - Introduction - Precautions - Equation Definition branch of physical science that deals with the relations between heat, work, temperature and other forms of energy  Thermodynamics: Heat Transfer If the water’s temperature is greater than the temperature of the body or body part in the water, then the temperature of the body or body part will increase. If the water’s temperature is cooler than the temperature of the body or body part, then the temperature of the body or body part will decrease. The rate of heat loss in body tissues to water at moderate temperatures is 25 times greater than the rate of heat loss to air at the same temperature. When the body or body part and the water are not moving, some heat will be transferred by conduction. However, the layer of water immediately adjacent to the skin may act as a “sealer,” which tends to inhibit conductive heat transfer. Agitation of the water in a whirlpool will limit this sealer effect. Heat will be transferred primarily by convection when the patient is moving in the water or when the water moves across the skin’s surface. The body can also lose heat by radiation and evaporation, depending on the amount of the body that is immersed and the temperature and humidity of the environment. Radiation is the exchange of electromagnetic energy between the warmer surface of the body and the cooler surrounding air. Evaporation is the loss of body fluids to the environment by sweating. These processes do not occur when the body surface is immersed in water.  Precautions for heat transfer Care must be taken to expose enough body surface to the environment outside the hydrotherapy tank or pool to allow for radiational cooling and evaporation. The ability of the body to lose heat to help maintain a constant core temperature is limited when the hydrotherapy environment is too warm or too humid. It is best to maintain the hydrotherapy environment at an air temperature between 65°F and 80°F (18.3°C and 26.7°C) and humidity between 50% and 65%.  Thermodynamics: Specific Heat Definition *Another property of water related to heat transfer is specific heat. This is a measure of the amount of energy (heat) stored in a material and the amount of energy required to heat the material. *Also, it is the amount of heat (calories) required to raise the temp of 1 gram of substance by 1°C. The amount of heat required to change the temperature of a given material is proportional to the mass of the material and to the temperature change. This can be expressed by the following equation: Q = mc ΔT Where Q is the amount of heat, m is the mass of the material, c is the specific heat of the material, and ΔT is the change in temperature.  Water has one of the highest specific heats of all substances. However, Heat transfer increases with velocity Also, water conducts (patient moving will lose temp 25 times faster than body temp faster than air patient at rest)  There is great difference between heat transfer in water and paraffin. Paraffin is usually applied to the skin safely at a temperature between 113°F and 129.1°F (45°C and 54°C), whereas water at these temperatures would feel uncomfortably hot and can burn the skin.