Elizabeth Brewer
September 6, 2005
Professor Bennett
Modalities 414
Assignment 1
Chapter 1
1. What is radiant energy and how is it produced?
Radiant energy is the process of emitting energy from a source in the form of
waves. Radiant energy in various forms can be produced by movement of electrons
when intense chemical or electrical force is applied to any object. (Pages 2-3).
2. What is the relationship between wavelength and frequency?
Wavelength is the distance between the peak of one wave and the peak of the
preceding or succeeding wave. Frequency is the number of wave oscillations or
vibrations occurring in one second. The relationship between them is that longer
wavelengths must have shorter frequencies and shorter wavelengths must have higher
frequencies. If you multiply wavelength and frequency, you can calculate velocity. (Page
6).
3. What are the characteristics of electromagnetic energy?
There are four characteristics of electromagnetic energy:
1. They may be produced when sufficiently intense electrical or chemical
forces are applied to any material.
2. They all travel readily through space at an equal velocity.
3. Their direction of travel through space is always in a straight line and
will alter this straight line travel only when they come in contact with
some other surface.
4. They may be reflected, refracted, absorbed, or transmitted, depending
on the specific medium that they strike.
(Page 4).
4. Which of the therapeutic modalities produce electromagnetic energy?
All modalities are examples of electromagnetic energy except for: ultrasound,
massage, traction, and intermittent compression. Some of these are cold packs,
hydrocollator packs, whirlpools, paraffin baths, and contrast baths. (Page 10).
5. What is the purpose of using a therapeutic modality?
The purpose of using any therapeutic modality is to stimulate a specific tissue to
perform its normal function. (Page 15).
6. According to the Law of Grotthus-Draper, what happens to electromagnetic energy
when it comes in contact with and/or penetrates human biologic tissue?
When electromagnetic energy comes in contact with the surface of the skin,
different things can happen. A portion of the energy may be reflected from the surface
and have no physiological response. The part that does not reflect will penetrate the
tissue and some will be superficially absorbed. If enough is absorbed, then vasodilation
of the blood vessels may occur. The energy that penetrates the tissue will go deep to the
fat and muscle. At the interfaces, the differences in density of the two tissues can cause
the energy to be refracted and alter its direction of transmission. (Pages 7-8).
Comment [j1]: Grade: 23/25. Pretty
good. Some comments below and just
general opinions as well. This is an
excellent start on these assignments.
Keep up the good work! ☺
7. Explain the cosine and inverse square laws relative to tissue penetration of
electromagnetic energy.
The cosine law states that the smaller the angle between the propagating ray in the
right angle, the less radiation reflected and the greater the absorption. An example would
be when using ultrasound treatment, keep the surface of the applicator as close to the
surface of the skin as possible. This minimizes the energy reflected. The inverse square
law says that the intensity of the radiation striking a particular surface is known to vary
inversely with the square of the distance of the source. The modalities that emit
electromagnetic radiations with relatively longer wave lengths have the ability to transmit
energy through the superficial tissue layers, thus penetrating to the deeper tissues where
they are absorbed. (Pages 8-9).
8. Which of the therapeutic modalities produces acoustic energy?
Ultrasound devices produce a type of energy that must be classified as acoustic
rather than electromagnetic energy. Ultrasound is a mechanical vibration-a sound waveproduced and transformed from high frequency electrical energy. (Page 12).
9. What are the differences between electromagnetic energy and acoustic energy?
Acoustic and electromagnetic energy are different in their physical characteristics.
Acoustic vibrations travel at a velocity significantly lower than electromagnetic
radiations. The relationship between velocity, wavelength, and frequency is a bit
different with acoustic energy than electromagnetic energy even though the inverse
relationship between wavelength and frequency still exists. Wavelengths are shorter in
acoustic vibrations rather than electromagnetic radiations at any given frequency.
Electromagnetic radiations are capable of traveling through space, whereas acoustic is
not. (Pages 12-13).
Chapter 2
1. How should the athletic trainer incorporate therapeutic modalities into a
rehabilitation program for various sports-related injuries?
Decisions regarding how and when a modality may best be incorporated should
be based on a combination of theoretical knowledge and personal experience. You
should not use modalities at random or based on what has been done before. Always
give consideration to what should work best for that specific injury. As an athletic
trainer, you should make your own decisions about which modality will be most
effective. (Page 18).
2. What are the physiological events associated with the inflammatory-response phase of
the healing process?
Many events happen during the inflammatory-response phase. The first is
cellular response where the leukocytes are delivered to the injured site to help dispose the
by-products and set stage for repair. The second event is vascular reaction where the
blood starts to clot and coagulate. The tissue also starts to grow and also causes a spasm.
The third event in the phase involves the chemical mediators. There are three mediators
that help limit swelling. The fourth event entails the function of platelets where they
attach to the collagen fibers and form a plug. The fifth event is the clotting process
which converts fibrinogen to fibrin and shuts blood supply to the area. (Pages 21-22).
Comment [j2]: An example of the
cosine law is that keeping the ultrasound
head at a 90 degree angle to the skin will
increase the amount of energy absorbed
by the tissues. Your example is actually
an example of the inverse square law.
3. How can you differentiate between acute and chronic inflammation?
As an athletic trainer, it is important to know the difference between inflammation
phases. The initial acute phase lasts from the time of injury and for a couple weeks. If
the inflammation lasts longer than one month, it is then classified as subacute
inflammation. If the inflammation lasts months or years, it is then chronic. Chronic
inflammation is a result of many acute microtraumas and overuse. One feature more
prominent in chronic inflammation is the rapid increase in tissue degeneration. Acute
and chronic inflammation are also different because of the cells they use. Chronic
inflammation uses lymphocytes, plasma cells, and macrophages. In acute inflammation,
neutrophil leukocytes are used. (Pages 21-22).
4. How is collagen laid down in the area of injury during the fibroblastic-repair phase of
healing?
During the fibroblastic-repair phase, the collagen fibers are randomly deposited
during formation of the scar on about day 6. As the collagen increases, the strength of
the wound rapidly increases in proportion to the rate of the collagen synthesis. (Page 25).
5. Explain Wolff’s Law and the importance of controlled mobility during the maturationremodeling phase of healing.
Wolff’s Law states that both bone and soft tissue will respond to the physical
demands placed upon them causing them to remodel or realign along the lines of tensile
force. The importance during this phase falls upon progressively being exposed to
weight bearing. Immobilization is important for scar formation, revascularization,
muscle regeneration, and reorientation of muscle fibers. (Pages 26-27).
6. What are some of the factors that can have a negative impact on the healing process?
Some factors that impede healing are the extent of injury, edema, hemorrhage,
muscle spasm, atrophy, and infection. These are just some of the many factors that affect
the healing process. (Pages 27-28).
7. Why is the immediate care provided following acute injury so important to the healing
process and the course of rehabilitation?
Immediate care is very important following an injury. You want to limit and
reduce swelling and pain as soon as possible. By controlling those factors from the
beginning you can limit the time an athlete has to rehab. (Page 29).
8. What specific modalities may be incorporated into treatment during the inflammatoryresponse phase?
Depending on the injury, the athletic trainer can use a variety of modalities such
as: cryotherapy, electrical stimulating currents, intermittent compression, or ultrasound.
(Page 23).
9. What specific modalities may be incorporated into treatment during the fibroblasticrepair phase?
Similar to the inflammatory phase, a variety of choices ranging from:
thermotherapy, electrical stimulating currents, low power laser, ultrasound, but also
incorporating range of motion. (Page 23).
10. What are the specific indications and contraindications for using the various
modalities?
Some indications for using modalities are: reduce inflammation, vasodilation,
wound healing, fracture healing, muscle strengthening, increase range of motion. Some
contraindications are: pacemakers, skin lesions, infections, pregnancy, poor circulation,
Comment [j3]: And, or course, the
rate of collagen synthesis is dependent on
Wolff’s Law, i.e., a little stress to the
joint (while not increasing injury) will
speed up collagen synthesis and therefore
wound repair
Comment [j4]: Or increased stress for
upper extremity or non-weight bearing
structures
Comment [j5]: Actually, I think
immobilization is horrible for muscle
regeneration and reorientation of muscle
fibers. Have you seen the size of a
muscle after you get out of a cast?
Comment [j6]: For the future, you
should always spell this out as instead of
shortening it. In written form, it is better
to be a little more formal than if you were
talking.
allergies. It is critical to use knowledge when deciding which modality to use and during
which healing phase. (Page 14).