Interventions Lecture 4 Flashcards
Muscle performance
capacity of a muscle to do work
(force * distance)
(formace * moment arm)
muscle performance is based on
- metabolic factors
- biomechanical factors
- neurological factors
- morphological factors
Key elements to muscle performance include
- strength
- power
- endurance
Strength biomechanical definition
ability of contractile tissue to produce tension with a resultant force based on the demands placed on the tissue
strength application definition
the greatest measurable force than can be exerted by a muscle (muscle group) to overcome resistance during single, maximal effort
functional strength
ability of a neuromuscular system to produce, reproduce, or control forces contemplated or imposed during functional activities in a smooth, coordinated matter
overload principle
a load that exceeds the metabolic capacity of a muscle (i.e., the muscle will be challenged) will lead to muscle performance improvement
- focus is on progressive loading
- you need to overload the muscle to increase strength
strength =
increase in resistance
endurance =
increase in time or repititions
SAID principle
extension of Wolff’s law (body systems adapt over time) specificity to what type of muscle performance needs to be improved must be accounted for
carry overs between strength & endurance training
- strength training – may increase in edurance
- endurance training has 0 effect on strength
- strength training at one speed – some improvement at other speeds
Reversibility Principle
Response to a resistance training program are not permanent unless improvements are regularly utilized for function
detraining
reduction in muscle performance that occurs due to cessation of training
Factors that influence tension
- Muscle size (hypertrophy)
- IIB fibers most effected
- more protein synthesis than degradation
- increase in individual muscle fiber size
- increase in number of fibers (hyperplasia); longituidnal splitting of fibers - occurs when size of the fiber becomes ineffeicient - fiber type
- muscle structure
- length-tension relationship
- connective tissue
- neurlogical
- nutrition
- type of contraction
- speed of contraction
Type of contraction
Ecentric > isometirc > concentric
At birth muscle accounts for ___ of body weight
25%
boys are ___% stronger than girls through puberty
10%
most strength gains in kids comes from:
appropriate play/activity without hypertrophy
At puberty (boys)
- muscle mass increases more than 30%/year
- muscle mass/body weight peaks before strength
At puberty (girls)
- increase in muscle mass (less than boys)
- strength peaks before body weight
muscle mass constitutes __ of an adult’s body weight
40%
____ decrease in strength from 3rd to 5th/6th decase
8-10%
older adults lose ___% of strength/decade
15-30%
decreased activity leads to
rapid decrease in strength and endurnace
decreased flexibility leads to
decreased force producing capacity of muscle and decreased speed of contraction
muscular endurance
ability of a muscle to contract repeatedly against a load (resistance), generate and sustain tension, and resist fatigue over an extended period of time
Endurance involves
manipulating a light load for many repititions or sustained contraction over an extended period of time
cardiovascular endurnace
“whole-body endurnace”; don’t confuse with muscular endurance - should explain the differences to paitents
muscular power
requires strength & endurance
work (force * distance) produced by a muscle per unit time
(force *distance / time)
-power is not always adressed in PT; PT is more functional
anaerobic power
high intensity exercise carried out over a short duration
-fiber Type II
aerobic power
lower intensity exercise carried out over a long duration
- fiber type I
- often interchanged with endurance
factors you can control in muscle performance
-biomechanics & neuro factors
torque
F *MA (moment arm is constantly changing with movement)
Load
1deg external factors
“moments” - recall the different moments that occur at the LE joints due to change in LOG
-changes with BOS - force in single limb stance vs. (B) limb stance
-constant change in COM during dynamic activity
-stress; stress/strain components
-momentum; consider change in force production due to speed of motion
neuroplasticity
how the CNS learns new movement behaviors; plasticity allows learning of new movement pattern