Muscular strength =
Muscular endurance =
Muscles = 40% of your body
mass
Basic Muscle Physiology Terms
Muscle fibers (cells)
Myofibrils
Myofilaments
Actin
Myosin
Sliding Filament Theory of Muscle
Contraction
Hypertrophy =
Atrophy=
The Sliding Filament Theory of Muscle Contraction
The Sliding Filament Theory of
Muscle Contraction
www.sci.sdsu.edu/movies/actin_myosin.html
Motor Units
TYPE of FIBER
Characteristic
Slow
Oxidative
(SO)
Fast Oxidative Fast Glycolytic
(FOG)
(FG)
Average Fiber %
50%
35%
15%
Speed of
Contraction
SLOW
FAST
FAST
Fatigue Resistance
HIGH
Intermediate
LOW
Aerobic Capacity
HIGH
intermediate
LOW
Anaerobic Capacity
LOW
Intermediate
HIGH
Mitochondria
MANY
MANY
FEW
Capillaries
MANY
MANY
FEW
Color of Fiber
RED
RED
WHITE
Glycogen Content
LOW
Intermediate
HIGH
Myoglobin Content
HIGH
HIGH
LOW
Fiber Diameter
SMALL
Intermediate
LARGE
Fast Twitch Type IIb
Slow Twitch
Type I
Intermediate Type
IIa
Muscle Fiber Recruitment
Isotonic vs. Isometric
Isotonic vs. Isometric
Two Phases of the Isotonic Contraction
Concentric
Eccentric
Isokinetic Contraction
Benefits of Muscular Fitness
Muscular Strength
a. Neural improvements
b. Hypertrophy
Muscular Endurance
Body Composition
a. weight management
1. basal metabolic rate
b. body image
Bone Density
Tendon, ligaments, joint
strength
Blood pressure
Blood cholesterol
Sarcopenia
Determinants of Muscular Fitness
Muscle fiber recruitment
Proportion of fibers recruited
Temporary muscular failure
Physiological changes
Hypertrophy= increase in number of
myofibrils
Rate of improvement
Depends on initial strength level
Genetic differences
Desired
outcome
Intensity
Repetitions
General
strength &
Endurance
40-80%
8RM
Max Strength
75100%
3RM
Strength
endurance
30-60%
15 RM
15-30
3-6
Fast
3-5
min.
Rehab from
injury
20-60%
15RM
15-25
1-5
Slow, pain
free
3-5
min.
Muscle mass,
bulk
80100%
5RM
1-10
Body Sculpting
10RM
10-12
6-10
3-8
Sets Contraction
3
Rest
Moderate
2-3
min.
5-10 Slow to
explosive
1-4
min.
5-15 Slow to
moderate
3-5
Slow to
moderate
1-3
min.
1-3
min.
ACSM’s Recommendations
Frequency
Intensity
Time
Type
2-3 days per week
lift to fatigue
1 set; 3-20 repetitions
8-10 exercises to work all
major muscle groups
Weight Training Guidelines
•Sequence
•Form
•Rest between sets
•Muscle balance
•Breathing
•Speed of movement
Major Muscle Groups