Ch9 Muscle Anatomy and Biomechanics

Question 1

Sliding Filament Theory

Answer 1

Myosin thick filaments and actin thin filaments have projections that slide across each other. These cause muscle contractions

Question 2

Sarcomeres

Answer 2

The two types of protein filaments (myosin and actin) are grouped into functional units called sarcomeres

Question 3

Muscles are categorized two ways

Answer 3

1) Speed of contraction (slow or fast)

2) Metabolic properties (energy manufacture)

Question 4

Muscles contract and pull on your bones via : _______

Answer 4

the tendon connection (muscles are a lever system, they pull- not push!)

Question 5

Type 1 / Slow Oxidative/ Slow Twitch

Answer 5

Have more mitochondria, are more fatigue resistant. Everyday use/ recruited for endurance events (marathon)

Question 6

Type 2x / Fast Twitch

Answer 6

Can generate energy rapidly, powerful muscle contractions for bursts of high power activity (sprinting, jumping, throwing)

Question 7

The Size Principle (muscle energy use)

Answer 7

Type 1 fibers are recruited first (and are smaller). As power/force output increases, bigger Type 2 fibers are recruited. This means to train type 2 fibers = workout at high intensity.

Question 8

Resistance Training for Strength

Answer 8

High resistance, low repetition weights (or high output like sprints/ explosive stop and go activities)- recruits Type 2 Fibers

Question 9

The All-or-Nothing principle

Answer 9

When a motor unit is activated, all its fibers contract fully.

Question 10

Exercise examples (3) to develop higher Power:

Answer 10

maximal sprints, jumps and throws

Question 11

Muscle Fibers: Type 1/ Type 2 involvement in an 800m sprint ? (High/ Low)

Answer 11

Both HIGH

Question 12

Muscle Fibers: Type 1/ Type 2 involvement in a marathon ? (High/ Low)

Answer 12

Type 1 -HIGH

Type 2- LOW

Question 13

Muscle Fibers: Type 1/ Type 2 involvement in Olympic Weightlifting ? (High/ Low)

Answer 13

Type 1 - LOW

Type 2- HIGH

Question 14

5 Types of Muscular Contraction

Answer 14

1- Isometric
2-Isotonic
3-Isokinetic 
4-Concentric 
5-Eccentric

Question 15

Isometric Contraction

Answer 15

A contraction with no appreciable change in muscle length –an external force has prevented the muscle from shortening (i.e. pushing against a wall)

Question 16

Isokinetic Contraction

Answer 16

The muscle shortens or lengthens at a constant velocity (rare in a training scenario except with swimming, or with rehab)

Question 17

Isotonic

Answer 17

Occurs when you a moving a constant mass (dumbbell, body weight) - once you have the weight moving, you don’t need to accelerate the load, just keep it moving (thanks to inertia)

Question 18

Concentric

Answer 18

Concentric contractions occurs when the muscle is both lengthening and shortening

Question 19

Two possible types of concentric muscle contractions

Answer 19

1) isotonic

2) isokinetic

Question 20

Eccentric contractions

Answer 20

Occur when the muscle is both contracting and lengthening–the muscle is trying to shorten but an external force us causing it to be lengthened (most common cause: gravity)

Question 21

Give an example and description of an eccentric contraction

Answer 21

When you lower a weight slowly you are contracting eccentrically, the force of gravity is pushing the weight down and you are contracting against this force.

Question 22

Muscle “Force-Velocity” relationship

Answer 22

The faster a muscle shortens, the less force it is capable of generating.

Question 23

Why can’t you exclusively train with heavy weights at low velocities for optimal power?

Answer 23

You are not training your nervous system to coordinate that strong musculature to peak power.

Question 24

As deep muscle temperature increases….

Answer 24

increases potential force output of muscles. This is generated from chemical reactions of muscle contractions = why ACTIVE warm ups are best

Question 25

Torque is affected by 2 things

Answer 25

1) muscle force

2) Distance from the joint (this is crucial! Think about how you wouldn’t open a door from the hinge)

Question 26

Why is torque important to consider in safety of resistance training exercises?

Answer 26

If the path of the dumbbell is not optimal it can generate a lot of external torque and can cause injury.

Question 27

Agonist muscle

Answer 27

the muscle that is contracting

Question 28

Antagonist muscle

Answer 28

muscle that produces the opposite toque to the agonist muscle