The Muscular SystemDay 1

Muscular System Overview

• Muscles pump blood through our bodies, move food through our digestive system, and control the movement or air in and out of our lungs

• Exercise is the key to health of the muscular system• In mass, muscle is the most abundant tissue in the body

• Our muscles consist of 75% water• Muscles work by means of two complementary or

opposing actions (contraction and extension)• A muscles is composed of bundles of fibers

Types of Muscle

• Smooth Muscle (Involuntary Muscle) – Movement of internal organs (eg. Intestines, bladder, etc.). Smooth muscle is not under conscious control

• Skeletal Muscle (Voluntary Muscle) – Muscles attached to bones that aid in body movements. An average adult male is made up of 40–50% of skeletal muscle and an average adult female is made up of 30–40%

• Cardiac Muscle – Striated tissue that forms the walls of the heart. Striated means Marked by narrow lines or grooves, usually parallel.

Skeletal MuscleType I – Slow Twitch

• Type I – “slow oxidative” or “slow twitch” muscle is dense with capillaries and is rich in mitochondria and myoglobin, giving the muscle tissue its characteristic Red color.

• The slow muscles are more efficient at using oxygen to generate more fuel (known as ATP) for continuous, extended muscle contractions over a long time.

• They fire more slowly than fast twitch fibers and can go for a long time before they fatigue. Therefore, slow twitch fibers are great at helping athletes run marathons and bicycle for hours.

Skeletal MuscleType II – Fast Twitch

• Because fast twitch fibers use anaerobic metabolism to create fuel, they are much better at generating short bursts of strength or speed than slow muscles. However, they fatigue more quickly.

• Fast twitch fibers generally produce the same amount of force per contraction as slow muscles, but they get their name because they are able to fire more rapidly.

• Having more fast twitch fibers can be an asset to a sprinter since he/she needs to quickly generate a lot of force.

Sport Fiber Type Used

Baseball Type I & II

Basketball Type II

Cross Country Skiing  Type I

Football  Type II

Gymnastics  Type II

Golf  Type II

Ice Hockey  Type II & I

Lacrosse   Type II & I

Softball   Type I

Soccer  Type I

Swimming - Sprint  Type II

Synchonized Swimming   Type I

Tennis   Type II & I

Track & Field   Type II

Volleyball   Type II & I

Weight Training   Type I

Fiber Type and Performance

• Our muscle fiber type may influence what sports we are naturally good at or whether we are fast or strong. Olympic athletes tend to fall into sports that match their genetic makeup. Olympic sprinters have been shown to possess about 80 percent fast twitch fibers, while those who excel in marathons tend to have 80 percent slow twitch fibers.

Can Training Change Fiber Type?

• This is not entirely understood, and research is still looking at that question. There is some evidence showing that human skeletal muscle may switch fiber types from "fast" to "slow" due to training but not the other way around.

• Fiber type is part of a great athlete's success, but it alone is a poor predictor of performance. There are many other factors that go into determining athleticism, including mental preparedness, proper nutrition and hydration, getting enough rest, and having appropriate equipment and conditioning.

Muscle Group Actions

• Agonist Prime Mover - A muscle that causes some specific movement to occur. It creates the normal range of movement in a joint by contracting. Agonists are also referred to as "prime movers" since they are the muscles that are primarily responsible for generating movement

• Antagonist - A muscle that acts in opposition to the specific movement generated by the agonist which is responsible for returning a limb to its initial position

Muscle Group Actions Cont’d

• Synergists – Smaller muscles which assist Prime Movers• Coordinated movement requires muscles primarily

responsible for movement agonists/prime movers, muscles that assist prime movers

synergists, and muscles that oppose prime movers

antagonist. Agonists produce most of the force needed for a movement. Synergists assist the action and fine tune the movement. The antagonist protects.

• Example: quadriceps and hamstrings. When your hamstrings (agonists) contract, your quadriceps (antagonists) oppose the motion preventing overstretching.

Agonist vs. AntagonistStep 1: Match the Agonist from Column 1 with the proper Antagonist from Column 2.

Step 2: In the Column called "Letter", match the muscle group with the proper Agonist/Antagonist pair.

Col 1 Agonist Col 2 Antagonist Letter Muscle Pair

A Anterior Deltoids Deltoids Abdomen and Lower Back

B Biceps Gastrocnemius Chest and Back

C Left External Oblique

Hamstring Front and Rear Shoulder

D Pectorals Latissimus Dorsi Front and Rear Thigh

E Quadriceps Posterior Deltoids Front and Rear Upper Arm

F Rectus Abdominus Right External Oblique

Left and Right side of Abdomen

G Tibialis Anterior Spinal Erectors Shin and Calf

H Trapezius Triceps Upper and Rear Shoulder

Homework…

• Major muscles Quiz

• ALL GROUPS must be ready to present, and have their Information Sheet prepared to be handed in

• Please attach your assignment sheet/rubric if you would like to receive a mark