Week 9 - Exercise in water Flashcards
What is hydrotherapy?
Exercise in warm water
OR
exercise in water
Origins of hydrotherapy?
→ Origins stem from ancient practices of immersion and hot and cold therapy
→ Western medieval revival late 1700’s in Europe, and the UK in the late 1840s (Victorian era)
→ Understanding and application has developed, but essential principles remain largely unchanged
4 principles of water as a physical material?
- Density and buoyancy
- Hydrostatic pressure
- Viscosity
- Thermodynamics (ability to hold/transfer heat)
What is density?
The relationship between the mass of an object (KG) and the amount of space that object occupies.
(m3).
→different materials have different density ratios
→ water at 4C has a density of 1000kg/m3 - 1000x more dense than air
→ salty water more dense as its more compressed - molecules are a lot closer together
What is archimedes principle?
When an object is immersed in water it displaces the same volume of water as the volume it occupies and receives an opposite force accordingly.
How is density applied to humans?
Density determines whether we float or sink.
Human beings are roughly 970kg/m3.
Very lean and muscly individuals = more dense (sink)
Individuals w/more adipose tissue = float
How can human density be manipulated?
Taking a deep breath
What is buoyancy?
Buoyancy is the relative force of displacing water and is in direct opposition to mass and gravity (it points upwards)
How does buoyancy change depending on how much of an object is submerged?
The more of an object that is submerged, the more buoyancy force is created and the less that object is subjected to the downwards force of gravity and mass.
- The more submerged in water we become, the less we seem to weigh.
- Immersed up to C7 = 10% bodyweight on land
Key points about buoyancy?
→ Buoyancy can either resist or assist depending on the direction of movement
→ Muscle contraction in a positively buoyant
environment is opposite to what is expected on land
How can buoyancy be applied to hydrotherapy?
→ Minimising weight-bearing and forces - increasing depth leads to reductions in load of body weight.
→ Reduction of loads through arthritic joints and fracture sites
→ Individuals who are wheelchair dependent may be able to ambulate when immersed in water.
What is hydrostatic pressure?
Density creates pressure - pressure = the force exerted by one substance on another
Hydrostatic pressure increases w/depth (about 1mmHg per 1.4cm) - deeper you submerge an object, the more pressure it is subjected to.
Therapeutic application of hydrostatic pressure?
Immersion in water acts to compress the human being. Deeper water causes more compression.
Systems relying on pressure see changes in function.
→ Fluids driven from extremities towards centre of body ↳ muscle blood supply increases followed by central CV system
→Kidney filtration increase and urine output increases
↳ dehydrate more quickly in pool.
→Thorax compressed creating increased work of breathing (+60% at neck immersion).
→Possible improvements in sensory information, proprioception etc. due to compression of our nervous system e.g. peripheral nerves.
What is water’s relationship with viscosity?
→It is inherently hydrophilic and possess a high degree of internal friction.
→Water molecules resist being separated from other molecules of water
→ Moving through water creates separation of water molecules - requires effort and produces a force known as drag
What is drag?
The force created by an object moving through a fluid.
→ Depends on the shape of the object and the speed at which that object is moving through the fluid
→ The bigger the object, the faster the object, the more drag.
→ There is also drag created by friction between the skin of the object and the water
