Muscular Strength

Muscular Strength

Muscular Strength

The greatest amount of force that a muscle or muscle group can produce in a single maximal effort.

Muscular Endurance

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

Muscular Power

The ability to produce force quickly.

Isotonic (dynamic) contraction

Contraction where tension is the same throughout the range of motion.

Concentric contraction

Muscle shortens with varying tension as it lifts a constant load.

Eccentric contraction

Muscle lengthens while developing force as the external resistance exceeds the muscle force.

Isometric contraction

Static contraction where tension is developed but there is no change in the angle of the joint or the length of the muscle.

Isokinetic contraction

Muscle is shortened at a constant velocity determined by computer instrumentation.

One Repetition Maximum (1 RM)

Maximum amount of weight lifted once.

Variable Repetition Maximum

Estimation of one repetition maximum from repetitions to failure.

Dynamometer Techniques

Strength testing using a spring or other device to measure force.

Computer-Assisted, Isokinetic Methods

Strength testing using computer-controlled equipment.

Muscle Cross Sectional Area

Strong positive relationship between muscle CSA and strength.

Body Size

Positive correlation between body size or mass and absolute strength.

Muscle Fiber Composition

Positive correlation between percentage of fast twitch fibers and strength.

Mechanical Factors

Initial length of muscle fibers, angle of pull, and speed of shortening affect force exerted by a muscle.

Muscle Strength and Sex

Average male is stronger than the average female, but individual differences exist.

Muscle Strength and Age

Muscle strength decreases with age, but resistance training can help maintain or increase strength.

Decreases

Refers to a reduction or decline in a particular aspect or parameter.

Increases

Refers to an augmentation or rise in a particular aspect or parameter.

Muscle mass

Refers to the total amount of muscle tissue in the body.

Muscle fiber size

Refers to the dimensions or diameter of individual muscle fibers.

Muscle metabolic capacity

Refers to the ability of muscles to produce energy and perform work.

Resting metabolic rate

Refers to the amount of energy expended by the body at rest.

Body fat

Refers to the adipose tissue or fat stored in the body.

Bone mineral density

Refers to the amount of minerals, such as calcium, present in bone tissue.

Physical function

Refers to the ability of the body to perform tasks and activities.

Purpose of Strength Assessment

• Assess muscular fitness

• Identify specific areas of weakness

• Monitor pogress in a rehabilitation program

• Measure effectiveness of a resistance training program

• Motivation for training

Strength Assessment Considerations

1. Standardized instructions should be given prior to testing

2. If a warm-up is given, it should be of uniform duration and intensity

3. Ensure that the angle of measurement of the limb or test device is consistent among subjects

4. Consider individual differences in body size and proportion when evaluating strength scores between individuals and groups

5. Test and training mode specificity are important for optimal expression of true strength gains

6. Safety is an important consideration when performing strength evaluations

7. Test administrators should be well trained and have a thorough understanding of all testing procedures and protocols

Hypertrophy

An increase in size of a cell such as a muscle fibre

Hyperplasia

An increase in number of cells such as adipose cells