Misc. MS

Question 1

Define body composition

Answer 1

The relative percentage of body weight that is comprised of fat and fat-free tissue.

Question 2

What is a healthy range of body fat for:
Males?
Females?

Answer 2

Males: 12-18%
Females: 18-23%

Question 3

How does hydrostatic weighing calculate body composition?

Answer 3

Hydrostatic weighing calculates the density of the body by immersing a person in water and measuring the amount of water that becomes displaced. The percentage of body fat is then determined by calculating the measured amount of water displaced in an equation based on Archimedes’ principle. Limitations include the need to account for residual lung volume; patient tolerance.

Question 4

How does plethysmography calculate body composition?

Answer 4

Plethysmography calculates the density of the body utilizing the amount of air displacement during testing within a specialized closed chamber. The change in pressure within the chamber is measured and converted to the percentage of body fat using a standardized equation.

Question 5

How does skinfold measurement calculate body composition?

Answer 5

Skinfold measurement determines overall percentage of body fat through the measurement of 9 standardized sites. The correlation relies on the theory that the amount of subcutaneous fat is proportional to the total fat in the body. Limitations include the requisite of an experienced examiner and variance from the standards based on gender, age, and ethnicity. Accuracy is within +/-3% with appropriate technique and equipment.

Question 6

Describe the skinfold measurement procedure.

Answer 6

1) All measurements should be taken on the right side of the body
2) Take multiple measurements at each site to ensure accuracy and retest if the difference is greater than 1-2 mm.
3) Skinfold calipers should be positioned one centimeter away from the examiners fingers when pinching the side, positioned perpendicular to the skinfold, and centered between the base and top of the fold
4) Wait one to two seconds before reading the caliper
5) Maintain pinching of the site during the reading of the caliper

Question 7

How does bioelectrical impedance analysis (BIA) calculate body composition?

Answer 7

BIA uses a small electrical current and measures the resistance or opposition to the current flow. This technique is based on the principle that resistance to electrical current is inversely related to the composition of water within the body. The formula of height^2/resistance is used for the general population while population specific equations are also available. The standard error compares to the accuracy of skinfold measurements at approx. +/-3%. Limitations include the requisite for the subject to be properly hydrated as well as following all guidelines for the BIA protocol.

Question 8

Describe the BIA protocol.

Answer 8

1) Abstain from eating or drinking within four hours prior to testing
2) Abstain from vigorous physical activity within 12 hours prior to testing
3) Urinate within 30 mins prior to testing
4) Avoid alcohol consumption for 48 hours prior to testing
5) Avoid excessive water intake prior to testing

Question 9

Describe the ideal plumb line alignment.

Answer 9

• Slightly posterior to coronal suture
• Thru the external auditory meatus
• Thru the axis of the odontoid process
• Midway thru the tip of the shoulder
• Thru the bodies of the lumbar vertebrae
• Slightly posterior to the hip joint
• Slightly anterior to the axis of the knee joint
• Slightly anterior to the lateral malleolus
• Thru the calcaneocuboid joint

Question 10

What are the 7 standard skinfold sites?

Answer 10

Abdominal
Triceps
Biceps
Chest/pectoral
Medical calf
Midaxillary
Subscapular
Suprailliac
Thigh

Question 11

Give examples of joints with a FIRM end-feel.

Answer 11

ankle DF
finger extension
hip internal rotation
forearm supination

Question 12

Give an example of a joint with a HARD end-feel.

Answer 12

elbow extension

Question 13

Give examples of joints with a SOFT end-feel.

Answer 13

knee flexion

elbow flexion

Question 14

Describe the different types of “abnormal end-feel”

Answer 14

Consists of any end-feel that is felt at an abnormal or inconsistent point in the range of motion or in a joint that normally presents with a different end feel.
Empty = cannot reach end-feel, usually due to pain
Firm = increased tone, tightening of capsule, ligament shortening
Soft = edema, synovitis, ligament instability/tear

Question 15

What is muscle insufficiency?

Answer 15

A muscle contraction that is less than optimal due to an extremely lengthened or shortened position of the muscle. Two types: active and passive

Question 16

Describe active muscle insufficiency.

Answer 16

When a two-joint muscle contracts (shortens) across both joints simultaneously. The muscle can not shorten beyond a certain limit without loosing tension and this is called active insufficiency ( e.g. maximal hip flexion with knee extension from a supine lying position).

Question 17

Describe passive muscle insufficiency.

Answer 17

When a two-joint muscle is lengthened over both joints simultaneously. The muscle can not e stretched beyond certain limits without causing pain. (e. g. when a person tries to flex the hip fully with maximal knee extension, he usually feels pain in the hamstring muscle if he has tight hamstrings).

Question 18

Describe the position of the hand during a power grip.

Answer 18

The fingers are in flexion and the wrist is in ulnar deviation and slight extension.

Question 19

What are the 4 types of power grips?

Answer 19

Cylindrical grasp
Fist grasp
Spherical grasp
Hook grasp

Question 20

Which joints of the hand are involved in a precision grip?

Answer 20

Metacarpophalangeal and interphalangeal joints

Question 21

What are the 3 types of precision grips?

Answer 21

Digital prehension grip (3-fingered pinch, holding a pen)
Lateral prehension grip (using a key)
Tip prehension grip (holding a needle)

Question 22

Define dynamometry. How is it used?

Answer 22

The process of measuring forces that are doing work. Dynamometry is used with a handheld dynamometer to measure grip strength, handheld dynamometer used to measure strength of the extremities through isometric contraction, and the dynamometer used to measure strength through isokinetic contraction

Question 23

Normally, a patient’s dominant grip strength is ___ to___ pounds greater than the non-dominant grip strength.

Answer 23

5 to 10 pounds

Question 24

Define isometric dynamometry.

Answer 24

Measures the static strength of a muscle group without any movement. The extremity is restrained by stabilization straps or stabilized with only verbal instructions.

Question 25

What are the benefits of isometric dynamometry?

Answer 25

Benefits include attaining peak and average force data, reaction time data, rate of motor recruitment, and maximal exertion data. This method is relatively safe, simple to use, easy to interpret data, and cost effective.

Question 26

What are the disadvantages of isometric dynamometry?

Answer 26

Need for caution with patients with acute orthopedic injury, osteoporosis or hernia. This method is contraindicated for patients with fractures and significant hypertension.

Question 27

Define isokinetic dynamometry.

Answer 27

Measures the strength of a muscle group during a movement with constant, predetermined speed. This device will alter the resistance to accommodate for the change in the length-tension ratio and lever arm throughout the entire arc of motion. The muscle groups will therefore maximally contract throughout the motion. Common speeds of motion include 60, 120, 180 deg per second.

Question 28

What are the benefits of isokinetic dynamometry?

Answer 28

The ability to test muscle strength at various speeds, ability to measure power, and the patient will never have more resistance than they can handle during isokinetic testing.

Question 29

What are the disadvantages of isokinetic dynamometry?

Answer 29

High cost of operation for the device, limitations in patterns of movement, a higher level of understanding is required by the patient, and does not truly correlate to function since people do not perform at a constant velocity during daily activities.