Lecture 5

Question 1

Muscular strength

Answer 1

The greatest amount of force that muscles can produce in a single maximal effort. (Kg)

Question 2

Power

Answer 2

Work per unit time

force x velocity

Question 3

Muscular endurance

Answer 3

ability of a muscle group to perform repeated contractions against a light load for an extended period of time

Question 4

Muscular power

Answer 4

the ability to exert a maximal force in as short a time as possible

Question 5

Benefits of strength training

Answer 5

Slow down the muscle loss that accompanies aging process
increase functional mobility
Increase the size and strength of muscle fiber
Increased tendon, ligament and bone tensile strength
Stronger muscles better protect the joint that they cross
improve physical appearance
Better strength in muscles of the trunk = prevent common postural problem
Stronger muscle = less likely to be injured
Improvement in self concept and self esteem

Question 6

3 types of Muscular contractions

Answer 6

1. Dynamic (isotonic ) contractions
2. Isometric contraction
3. Isokinetic contraction

Question 7

Dynamic (isotonic) contraction

Answer 7

Dynamic
Range of motion when muscle perform work
Concentric contraction - muscle shortens
Eccentric contraction - Muscle lengthens ( used in resisting gravity )

Question 8

Isometric contraction

Answer 8

Static contraction . No change in angle of the joint or the length of the muscle. eg. Jackson upright row test

Question 9

Isokinetic Contraction

Answer 9

Muscle is shortened at constant velocity
Exert maximal force throughout the full range of motion
Usually need electronic equipment

Question 10

Purpose of strength Assessment

Answer 10

1. Assess muscular fitness
2. Identify specific areas of weakness
3. Monitor progress in a rehabilitation program
4. Measure effectiveness of a resistance training program
5. Motivation for training

Question 11

Strength assessment techniques

Answer 11

1. One repetition Maximum =
2. Dynamometer techniques
3. Computer-assisted, isokinetic methods

Question 12

One Rep Maximum

Answer 12

Maximum amount of weight lifted once

Estimated One rep maximum = (weight lifted )/ [1.0278 - (n x 0.0278)]

Question 13

Dynanometer techniques

Answer 13

Usually consist of a spring of some type
deform when a certain amount of force is applied to it
eg. Hand grip dynamometer
Measures isometric strength

Question 14

Computer assisted, isokinetic methods

Answer 14

Using isokinetic machine, but many of these machines can also test strength in isometric, concentric, and eccentric modes.

Question 15

Strength assessment considerations

Answer 15

1. Standardized instructions should be given
2. Warm up should be uniform duration and intensity
3. Ensure that the angle of measurement is consistent
4. Consider individual differences in body size and proportions
5. Test and training mode specificity are important
6. Safety
7. Test admin must know what they are doing

Question 16

Effect of various factors on Strength

Answer 16

1. Muscle cross sectional Area
2. Body size,
3. Muscle fiber composition
4. Mechanical factors
5. Sex and Age

Question 17

1. Muscle cross sectional Area

Answer 17

1. Muscle Cross Sectional Area - there is a strong positive relationship between muscle
   CSA and strength.
   Muscles increase in strength by increasing their size and by enhancing the recruitment and firing rates of their motor units.
   Hypertrophy accounts for most increase in muscle

Question 18

Hypertrophy

Answer 18

Increase in size of cell

Question 19

Hyperplasia

Answer 19

Increase in number

Question 20

Myonuclear addition

Answer 20

Myofibrillar proteins increase

Myofiber CSA increase

Question 21

Body size

Answer 21

Body Size - there is a positive correlation between body size or mass and absolute strength.
There is a negative correlation between body mass and the strength/mass ratio. The strength to mass ratio directly reflects an athlete’s ability to accelerate his or her body.

Question 22

Muscle fiber conposition

Answer 22

For a given size of muscle, positive correlation between % of fast twitch fiber and strength

Question 23

Mechanical factors

Answer 23

Force exerted by a muscle is affected by:

1. Initial length of the muscle fiber
2. The angle of the pull
3. The speed of shortening

Question 24

Sex

Answer 24

Average male is physically larger than average female
Difference in body composition = average male has more muscle and less fat due to testosterone
Larger muscles are stronger muscles
Body proportion differences
Cultural factors - less emphasis on strength activities for females

Question 25

Age

Answer 25

During this time period the increase in muscle mass in both sexes is due to hypertrophy of individual muscle fibers and not hyperplasia.
Maximum strength of men and women is generally achieved between ages of 20-30 years = muscle cross sectional area is usually the greatest
After, progressive decrease in strength