Week 5 Muscular Strength Flashcards
Muscular strength
the greatest amount of force that muscles can produce in a single max effort
Muscular endurance
ability to perform repeated contractions of a muscle group for a period of time
Muscular power
work over time
- force x velocity
- essentially power involves strength and speed
what are some of the benefits of strength training - there are 8
- reduce/slow aging loss of muscle
- increase functional mobility
- increase size and strength of muscle fibers
- stronger muscles protect joints
- improved physical appearance
- improve posture
- reduce chance of injury
- improve self esteem
what are the three types of Muscular Contraction?
- Dynamic (isotonic) contraction
- Isometric contraction
- Isokinetic Contraction
What is a dynamic (isotonic) contraction
bony levers move in a range of motion to perform work
- free weights or machines
eg: bicep curl
Dynamic contraction - Concentric contraction
muscle shortens with tension as it lifts a constant load
dynamic - eccentric contraction
external resistance exceeds muscle force, the muscle lengthens while developing force
- usually resisting gravity
isometric contraction def and example
- this is a static contraction so there is tension but no change in the angle of the joint or length of the muscle
eg: upright row from lab
isokinetic contraction
the muscle is shortened at a constant velocity by a measuring machine
- max force throughout full range of motion
what are the 5 purposes of strength assessment
- assess muscular fitness
- identify specific areas of weakness
- monitor progress in rehab
- measure effectiveness of resistance training
- motivation for training
what are the three strength assessment techniques?
- one repetition maximum
- dynamometer techniques
- computer-assisted, isokinetic methods
what is one repetition maximum and what does it measure
- uses free weights or machines and allows for dynamic muscle contractions
- measures the max amount of weight that can be lifted at once
what is a critque of 1 repetition maximum
can be dangerous for indviduals who are not experienced in weight lifting
what is estimated one repetition maximum and why do we estimate?
we are able to estimate 1 rep max from repetitions to failure on a machine or weight
number of reps must not go past 10 but this is safer than using 1-RM for. begginers
what strength do dynamometers measure and what are they?
a spring grip machine
this measures isometric strength
- inexpensive and reliable
what are computer-assisted, isokinetic methods
this is a type of equipment where the computer can be programmed at any initial force, angle, velocity or number of repetitions
- measures peak force
- very reliable and accurate but expensive
what are some of the important strength assessment considerations
- standardized instructions and warm-up
- angle of measurement must be consistent
- consider individual differences in size and proportions
- specifing test and training mode (concentric, eccentric, isometric, iskinetic) should assess muscle with correct strength test
- safety
- test administrators should be well trained and understand procedure
what are the 5 factors on strength
- muscle cross sectional area
- body size
- muscle fiber composition
- mechanical factors
- sex and age
what effect does the muscle cross sectional area have on strength?
- the picture of trathalone thighs vs 80 yr old
- strong positive relation between muscle CSA and strength
how does more muscle imrpove for your strength?
when muscle size increases their strength increases aswell by the increase of firing rates of their motor units
what is hypertrophy
an increase in the SIZE of a cell - (like a muscle fiber)
- accounts for most of increase of CSA
what is hyperplasia?
an increase in the NUMBER of cells such as adipose cells
- only evidence that this occurs in animals
how does body size impact strength?
positive correlation between size/mass and strength
- smaller athletes are strnger kilogram for kilogram than larger athletes - ex: 132lb 4”10 weight lifter can light 3.2x body mass but 6’2 290 pound can only lift 1.9 x body mass
