Muscular strength =Muscular endurance =

Muscles = 40% of your body mass

Basic Muscle Physiology TermsMuscle fibers (cells) MyofibrilsMyofilaments Actin MyosinSliding 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

CharacteristicSlow Oxidative (SO)

Fast Oxidative (FOG)

Fast Glycolytic (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

Muscular Strength a. Neural improvements b. HypertrophyMuscular EnduranceBody Composition a. weight management 1. basal metabolic rate b. body imageBone DensityTendon, ligaments, joint strengthBlood pressureBlood cholesterolSarcopenia

Benefits of Muscular Fitness

Muscle fiber recruitmentProportion of fibers recruitedTemporary muscular failure

Physiological changesHypertrophy= increase in number of myofibrils

Rate of improvementDepends on initial strength level

Genetic differences

Determinants of Muscular Fitness

Desired outcome

Intensity Repetitions Sets Contraction Rest

General strength & Endurance

40-80% 8RM

6-10 3 Moderate 2-3 min.

Max Strength 75-100% 3RM

3-8 5-10 Slow to explosive

1-4 min.

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

80-100% 5RM

1-10 5-15 Slow to moderate

1-3 min.

Body Sculpting 10RM 10-12 3-5 Slow to moderate

1-3 min.

ACSM’s RecommendationsFrequency 2-3 days per weekIntensity lift to fatigueTime 1 set; 3-20 repetitionsType 8-10 exercises to work all major muscle groups

•Sequence

•Form

•Rest between sets

•Muscle balance

•Breathing

•Speed of movement

Weight Training Guidelines

Major Muscle Groups