Ch9 Muscle Anatomy and Biomechanics Flashcards
Sliding Filament Theory
Myosin thick filaments and actin thin filaments have projections that slide across each other. These cause muscle contractions
Sarcomeres
The two types of protein filaments (myosin and actin) are grouped into functional units called sarcomeres
Muscles are categorized two ways
1) Speed of contraction (slow or fast)
2) Metabolic properties (energy manufacture)
Muscles contract and pull on your bones via : _______
the tendon connection (muscles are a lever system, they pull- not push!)
Type 1 / Slow Oxidative/ Slow Twitch
Have more mitochondria, are more fatigue resistant. Everyday use/ recruited for endurance events (marathon)
Type 2x / Fast Twitch
Can generate energy rapidly, powerful muscle contractions for bursts of high power activity (sprinting, jumping, throwing)
The Size Principle (muscle energy use)
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.
Resistance Training for Strength
High resistance, low repetition weights (or high output like sprints/ explosive stop and go activities)- recruits Type 2 Fibers
The All-or-Nothing principle
When a motor unit is activated, all its fibers contract fully.
Exercise examples (3) to develop higher Power:
maximal sprints, jumps and throws
Muscle Fibers: Type 1/ Type 2 involvement in an 800m sprint ? (High/ Low)
Both HIGH
Muscle Fibers: Type 1/ Type 2 involvement in a marathon ? (High/ Low)
Type 1 -HIGH
Type 2- LOW
Muscle Fibers: Type 1/ Type 2 involvement in Olympic Weightlifting ? (High/ Low)
Type 1 - LOW
Type 2- HIGH
5 Types of Muscular Contraction
1- Isometric 2-Isotonic 3-Isokinetic 4-Concentric 5-Eccentric
Isometric Contraction
A contraction with no appreciable change in muscle length –an external force has prevented the muscle from shortening (i.e. pushing against a wall)
Isokinetic Contraction
The muscle shortens or lengthens at a constant velocity (rare in a training scenario except with swimming, or with rehab)
Isotonic
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)
Concentric
Concentric contractions occurs when the muscle is both lengthening and shortening
Two possible types of concentric muscle contractions
1) isotonic
2) isokinetic
Eccentric contractions
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)
Give an example and description of an eccentric contraction
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.
Muscle “Force-Velocity” relationship
The faster a muscle shortens, the less force it is capable of generating.
Why can’t you exclusively train with heavy weights at low velocities for optimal power?
You are not training your nervous system to coordinate that strong musculature to peak power.
As deep muscle temperature increases….
increases potential force output of muscles. This is generated from chemical reactions of muscle contractions = why ACTIVE warm ups are best
