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
dynamic stress
muscle contracts and changes the length of the joint
best for gaining strength that can be translated to other physical activity
concentric
shortens as enough force is applied to overcome resistance
eccentric
lengthens when resistance is greater than the force applied
resistance
Constant: constant load is applied throughout full range of motion
Variable: load changes to provide maximum load throughout the range of motions
dynamic forms of exercise
eccentric loading, plyometrics, speed loading, isokinetic loading
eccentric loading
load is placed as the muscle lengthens
Negatives: specifically used to overload the muscle eccentrically
plyometrics
eccentric loading and stretching followed by forceful contraction
explosive strength, maintain bone density
speed loading
move weight as quickly as possible
isokinetic loading
exerting force at a constant speed against equal force
methods and equipment
free weights, machines, kettlebells, body weight, resistance bands, stability balls, vibration training, pilates, medicine balls, suspension training, power-based, blood flow restriction training
FITT-VP principle
frequency, intensity, time, type, volume, progression
what are ergogenic aids used for
-enhance muscle hypertrophy, strength, power, and endurance
- speed up recovery and prevent overtraining
- increase training intensity and aggressiveness
- control fat, body water, and appetite
steroid side effects
- liver toxicity and tumors
- decreased HDL
- Cardiac arrhythmia
- reduced sperm count
- lower testosterone production
- increased BP
- glucose intolerance
- lowered immune function
- psychological disturbances
- masculinization in women and children
creatine
- increases creatine phosphate in muscle by 20%
- maintains ATP levels
- Improves short-term function
protein and amino acid
promote muscle hypertrophy, lower body fat, stimulates growth hormone release
