Chapter 18: Muscle contraction and movement Flashcards
At what part of body lifts that female and male has distinguish different muscular strength?
upper body lift (bench press)
Does the concentric contraction accelerate or decelerate? eccentric?
concentric contraction accelerate
eccentric contraction decelerate
What muscle type that generate the greatest force? highest velocity?
pennate, bipennate, multipennate
parallel fibers in a fusiform manner
What does the maximal velocity depend on?
the cycle rate of number cross bridges
What does the maximal force depend on?
the number of cross bridges
What determine the maximal number of cross bridges?
the sarcomere length (2-2.25)
What does 1RM measure?
dynamic resistance strength
Identify the three most probably causes of fatigue during short-term, high-intensity
anaerobic exercise.
depletion of PC stores
lactate interferes with cross-bridgings
accumulation of hydrogen ions
Identify the three most probable causes of fatigue during long-term, moderate to
heavy, submaximal aerobic exercise.
depletion of glycogen
accumulation of hydrogen ions
lactate interferes with cross bridging
What are the two uniques cause of muscle fatique in static exercise?
Occlusion of blood flow
Inhibition of motor cortex via sensory fibers in muscle
What are the exercises use whole contraction of muscle?
dynamic, static and isokinematic exercise
What is the dynamic exercise?
Exercise in which muscle forces vary as due to change of muscle length accordingly to the movement around joints
Isotonic exercise
Exercise in which the muscle force is constant
Isokinetic exercise
exercise in which velocity of contraction is constant
Isokinematic exercise
exercise in which whole muscle contraction rate of limb displacement and joint is held constant
Isometric exercise
exercise in which the length of muscle fiber is constant (velocity is zero)
Static exercise
exercise in which there is no displacement or joints movement
What exercise create the greatest force? least force?
eccentric dynamic exercise
concentric dynamic exercise
what determine the force generated in muscle fibers?
neural factors ( frequency of stimulus and the recruitment of # of motor neurons)
Length-tension relationship
The greatest force is generated is when at the optimal length of sarcomere (2-2.25)
What happen when muscle fibers contract at optimal length?
the number of cross bridges are greatest
Force-velocity relationship
the shortening velocity increases when the force decreases
How does the muscle perform with prestretch?
muscle fibers generate greater force with prestretch without
What happen when exercise damage the skeletal muscle?
It cause the leaking membrane, increase Ca2+, which degrade Z-disc and cause inflammation
Treatment for DOMS?
Anti-inflammation drugs
Massage, Compression
What is delay-onset muscle soreness?
the condition which you feel pain when palpate your muscle, occur 8hrs after exercise and peak from 24-48 hours and disappear after 96 hrs
What are the laboratory methods to measure the muscular strength?
EMR: measure the motor units recruitment
Isokinetic: force, velocity, power
Force transducer: muscle static strength and endurance
What cause the decline in muscle strength?
muscle mass degrade - 25% for both male and femal
loss of contractile properties of muscle fibers
reduced activation of motor units, denervation
Does the ST lose more than FT when aging?
No, they are losing both equally
