Chapter 4 Flashcards
muscle fibers
- individual muscle cell, each cell contain multiple nuclei
- bundle of fascicles
- single muscles are made up of multiple fascicles
- held together by connective tissue
how are muscle fibers classified
strength, speed of contraction, and energy source
what are muscle fibers made of
myofibrils
sarcomere
- contractile unit of myofibril
- composed of actin and myosin molecules
- contraction are produced when the myosin glides across the actin
hypertrophy
myofibrils increase in size and number
hyperplasia
increased number of fibers instead of larger size
atrophy
decrease in muscle fiber size
slow twitch fibers
fatigue resistant
slower contraction than fast-twitch
primarily fueled by aerobic system
reddish color
fast twitch fibers
rapid and forceful contraction
fatigue quickly
primarily fueled by anaerobic system
preferentially increased with training
whitish color
motor unit
nerve connected to muscle fibers
a small unit is slow twitch, a large unit is fast twitch. The number of units recruited is dependent on the amount of strength needed
axons
covered in myelin and the more motor skills causes more myelin to lay down on the axon. This improves neural conduction and improves skills
physiological changes from strength training
muscle learning: increases strength
maintain motor nerve connections
decrease bone loss when practiced regularly
metabolic and hearth health
improves glucose metabolism
increases vo2max
lowers blood pressure
increases HDL and lowers LDL
blood vessel health
assessing strength and endurance
strength: 1 rep max
endurance: counting maximum reps of an exercise
static stress
isometric contraction
important for developing core muscles for support of spine and torso and useful after injury to improve strength with minimal movement
