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Motor Unit/How to Increase
single motor neuron and all the muscle fibers it innervates- once fired all units WILL maximally contract; increase motore units by exercising which increases force! TERM 2
Difference Between Minimal vs. Maximal
Resistance
DEFINITION 2 Number of muscle fibers recruited TERM 3
Fiber Recruitment Increased By:
DEFINITION 3
- Activate those motor units containing greater # of muscle fibers 2. Activate more motor units 3. Increase frequency of motor unit activation. TERM 4
First 2 Weeks of Strength Building
DEFINITION 4 Neouromuscular brain is being worked bc you are activating motor units that haven't been used before. Strength might increase but muscle growth comes later. TERM 5
Muscle Fibers per Motor Unit
DEFINITION 5 The eye requires about 10 precise motor fibers while larger muscles (quads) contain a few thousand less complex muscles fibers.
How Do Muscle Fibers Contract
Motor Unit recieves an action potential from brain and spinal cord, through the axon, and to muscle TERM 7
Subthreshold
Stimulus
DEFINITION 7 If stimulus is not strong enough to cause an action potential, a contraction does not occur (Paralesis) TERM 8
Threshold
Stimulus
DEFINITION 8 When stimulus becomes strong enough to produce an action potential in a single motor unit axon, threshold occurs and all the muscle fibersin the motor unit contract. (When neuron fires, minimal amount of activity needed). TERM 9
Submaximal
Stimuli
DEFINITION 9 Stimuli that are stronger to the point of producing action potentials in additional motor unit. TERM 10
Maximal
Stimulus
DEFINITION 10 Occurs when all action potentials are produced in motor units of particular muscle (No matter how hard you stimulate, contraction won't increase after max).
Muscle Force-Velocity Relationship
As you hold more weight (resistance) the shortening velocity decreases. As force increases, eccentric velocity quickens. TERM 17
Angle of Pull
DEFINITION 17 Angle b/w line of pull of the muscle and the bone on which it inserts; Rotary Component- the closer angle of pull is to 90 degrees, the greater the rotary component. Stabilizing Component- pull is less than 90 degrees Dislocating Component- pull is greater than 90 degrees TERM 18
Active/Passive Insufficiency
DEFINITION 18 Active- muscle becomes shortened to point that it can not generate or maintain active tension. Passive- opposing muscle becomes stretched to the point where it can no longer lengthen and allow movement (flexing hip and trying to extend knee) TERM 19
Biomechanics
DEFINITION 19 study of mechanics as relates to functional and anatomical analysis. TERM 20
Mechanics
DEFINITION 20 Study of physical actions of forces (static and dynamic) Static- study of systems in constant motion (balanced; ice skating) Dynamics- study of systems in motion with acceleration
Kinematics/Kinetics
KMatics- description of motion and includes consideration or time, displacement, velocity, acceleration, and space factors (quality) Kinetics- study of forces associated with motion of body (quantity) TERM 22
Mechanical Advantage/Radius Wheel Larger
than Axle/Single Pulley
DEFINITION 22 Load divided by effort; MA is greater than 1; Single Pully MA is 1 TERM 23
3 Machines in Body
DEFINITION 23
- Levers 2) Wheel-Axles 3)Pulleys TERM 24
Two Bones of Shoulder Girdle
DEFINITION 24
- Clavicle 2) Scapula - ONLY bony link to axial skeleton is sternum articulation TERM 25
Scapulothroacic
DEFINITION 25 Joint: Posterior articulation between scapula and ribcage
Depression/Elevation
Downward or Inferior Movement. Upward or superior movement (shoulder shrug) TERM 32
Anterior Tilt
DEFINITION 32 (Upward) Rotational movement of scapula about frontal axis occurring during glenohumeral hyperextension TERM 33
Posterior Tilt
DEFINITION 33 ( Dowward) Rotation of scapula about frontal axis occurring during hyperflexion of glenohumeral TERM 34
Lateral Tilt
DEFINITION 34 (Protraction) Scapula rotate about vertical axis resulting posterior movement of medial border and ANTERIOR movement of lateral border. TERM 35
Medial Tilt
DEFINITION 35 (Retraction) Scapula rotates about vertical axis resulting in anterior movement of medial border and POSTERIOR movement of lateral border
How Shoulder Joint Movements Occur
Muscles of shoulder girdle are essential in providing a scapula-stabilizing effect; shoulder girdle muscles contract to maintain scapula in relatively static position (SYNERGIST) TERM 37
Muscles of Shoulder Girdle
DEFINITION 37
- Trapezius 2) Rhomboid 3) Levator Scapula 4) Serratus Anterior 5) Pectoralis Minor TERM 38
Scapula Abduction
DEFINITION 38 Pectoralis Minor and Serratus Anterior (the up part of the push-up). TERM 39
Scapula Adduction
DEFINITION 39 Middle Trapezius and Rhomboids TERM 40
Scapula Upward
Rotation
DEFINITION 40 Middle Trap, Lower Trap, Serratus Anterior
Lever
a rigid bar that turns about an axis of rotation or fulcrum TERM 47
In the Body (levers)
DEFINITION 47
- Bones are Bars(resistance) 2) Joints are Axes 3) Muscles are Force TERM 48
First Class Lever
DEFINITION 48 (FAR) SeeSaw- Resistance and Force Arm are balanced; produce speed and ROM when axis is close to force Examples: Crowbar, Scissors Tricep Extension (F= Tricep A= Elbow R= Forearm(Weight in Hand)) TERM 49
Second Class Lever
DEFINITION 49 (ARF) Produces force movement since Force Arm is ALWAYS longer than the Resistance Arm having a MA greater than 1. Example: Wheelbarrow, Nutcracker, Loosening Lug Nut, Plantar Flexion (A= Ball of Foot R= Tibial Articulation F= Calcaneus) TERM 50
Third Class Lever
DEFINITION 50 (AFR) Most common in human body; Resistance Arm is ALWAYS greater than Force Arm having MA less than 1. Example: Paddling Boat, Shoveling, Bicep Brachii in Elbow Flexion (A= Elbow F= Bicep R= Hand (Weight))
Torque & Eccentric
Force
The turning effect of an eccentric force which is force applied in direction not in line with center of rotation of an object w/ fixed axis; Determine Torque by Force x Force Arm TERM 52
Relation with ROM and Speed
DEFINITION 52 Increase Force Arm= Decrease ROM and Increase Speed Decrease Force Arm= Increase ROM and Decrease Speed TERM 53
Inverse Relation B/W Length of
Two
DEFINITION 53 Long Force Arm= less force required to move the lever if resistance and resistance arm remain constant. Shortening Resistance Arm= greater resistance to be moved if force and force arm remain constant TERM 54
Proportional Relation B/W Length of
Two
DEFINITION 54 Greater Resistance Arm= Greater Foce or Longer Force Arm Greater Force Arm= Greater Amount of Resistance to move Longer Resistance Arm TERM 55
Increasing Insertion of Bicep by 2 Inches
DEFINITION 55 If you were to move your bicep 2 inches from its insertion point you would calculate how much pull (force) is needed by multiplying Force x Force Arm (2 inches)= Resistance ( lbs) x Resistance Arm (18 inches). (F2=360) You would then divide by 2 to come to the answer of 180 lbs of Force.
Pulley
Function to change effective direction of force application (MA=1). Each additional pulley increases MA by 1. Pulley in Body= Lateral malleolus acting as pulley around tendon of peroneus longus TERM 62
Two Types of Motion
DEFINITION 62
- Linear Motion 2) Angular Motion TERM 63
Linear Motion
DEFINITION 63 Motion along a line; Rectilinear- motion along a straight line (fast pitch). Curvilinear- motion along a curved line (Football pass). TERM 64
Angular Motion
DEFINITION 64 Rotation along an axis (spin). (Football Pass). You can take rotary out and have a curved motion, but NOT rectilinear TERM 65
Displacement
DEFINITION 65 Actual distance that the object has been displaced form original starting point. If a person starts at point A, turns right and walks to point B, then turns left and walks to point C, you would measure in a straight line from point A to point C to determine displacement. If the person walked back to point A, the displacement would be 0. (Can be Angular and Linear).
Distance
Actual sum length of measurement traveled. TERM 67
Speed
DEFINITION 67 (Distance divided by Time) How fast an object moves or distance that an object moves in specific amount of time. TERM 68
Velocity
DEFINITION 68 Included direction and describes RATE OF DISPLACEMENT (If you were to move your body forward and backwards, your velocity would be 0). TERM 69
1st Law of Motion
DEFINITION 69 Inertia: A body in motion remains in motion at same speed in straight line until acted upon by a force. A body at rest remains at rest until acted upon by a force. TERM 70
Inertia
DEFINITION 70 Resistance to action or change (body is resistance to acceleration or deceleration). Based upon MASS (Greater Mass= Greater Inertia). Example: Sprinter on Block
3rd Law of Motion
Reaction: For every action there is an equal and opposite reaction. (Walking on the ground- As we push down and back on the ground, the ground is pushing up and forward upon us)= GROUND REACTION FORCE TERM 77
Friction
DEFINITION 77 Force that results from resistance b/w surfaces of two objects: Static Friction (Always Greater)- amount of friction between objects at rest. Kinetic Friction- amount of friction between objects that are sliding. Rolling Friction- resistance to an object rolling across a court (always lesser than static or kinetic). TERM 78
Balance
DEFINITION 78 Ablitiy to control equilibrium, either static or dynamic TERM 79
Equilibrium
DEFINITION 79 No change in speed or direction (zero acceleration). Static- body is at rest. Dynamic- all applied and internal forces action on the moving body are in balance, movement with unchanged speed and direction TERM 80
Stability
DEFINITION 80 is resistance to a change is body's acceleration or disturbance of body's equilibrium. To enhance stability, you must determine the center of gravity
General Factors for Equilibrium, Stability, and
Balance
- Balance when CoG falls within base of support. 2) Larger the Base of Support= More Balance. 3) Greater the Weight= More Balance. 4) Lower CoG= More Balance. 5) Balance is LESS if CoG is near the edge of the base. 6) Oncoming force, stability enhanced by creating enlarged base of support in direction of applied force.
- Equilibrium enhanced by increasing friction b/w body and surface. 8) Rotation around axis aids balance (bike). 9) Kinesthetic physiological functions contribute (inner ear, vision, touch, etc.).
