What is muscular strength
The greatest amount of force muscles can produce in a signle maximal effort
What is muscular power
Work/Force per unit time (strength over a unit of time)
Benefits of strength training
-Slow down sarcopenia
-Increase functional mobility
-Increase size and strength of muscle fibers
-increase tendon, ligament and bone tensile strength
-Protect joints the muscle crosses better
-Helps posture
-Less likely to be strained and injured
-Improve self esteem and self-perception
Types of muscular contraction
Isotonic contraction
Isometric contraction
Isokinetic contraction
What is isotonic contraction
The bony levers move through a ROM when the appropriate muscles perform work.
Movement at same tone/effort
Types of dynamic contraction
Eccentric and Concentric
What is isometric contraction
Tension is developed but there is no change in the angle or position of joint
What is isokinetic contraction
Muscle is shortened at a constant speed/velocity (allows maximal force through full ROM)
What is one rep max
The maximum amount of weight lifted once
What is the dynamometer techniques
A strength testing technique consisting of a spring being deformed a certain amount when force is applied to it
What type of strength does the dynamometer measure
isometric strength
What are all the strength assessment techniques
-One rep max
-Dynamometer techniques
-Computer assisted, Isokinetic Methods
What is the isokinetic method of measuring strength
A computer assisted program that can be programmed at any initial and final force, angle, velocity, or number of reps
Measures peak torque using a force transducer and joint angle using an electro goniometer
What are the strength assessment considerations
-standardized instructions should be given
-Warmup should be uniform duration and intensity
-Angle of measurement is consistent
-take into account body size and proportion differences
-Test and training mode of muscle should be specific
-Safety
-Test administrators well trained
How does muscle cross sectional area affect strength
There is a positive relationship between CSA and strength
increase in size recruitment, and firing rates of motor units = more strength
What is hypertrophy
An increase in size of a cell such as a muscle fiber
What is hyperplasia
an increase in number of cells such as adipose cells
What accounts for most MCSA
Muscle fiber hypertrophy
What stays consistent during hypertrophy
Ratio of nuclei to fiber volume ratio
What does body size cause strength wise
There is a positive correlation between body size and absolute strength but a negative correlation between body mass and strength/mass ratio
Do slow or fast twitch fibers cause more strength
fast twitch
What is the force exerted by a muscle affected by
-The initial length of the muscle fibers
-The angle of pull of the muscle on the bony skeleton
-The speed of shortening
What happens to muscle strength after age 16 (in terms of sex)
The average female is about 2/3 as strong as the average male in terms of force
