Lecture 1- Biomechanical Principles, Intro to Kinesiology, Basic Structure and Function of Human Joints, Muscle Structure and Function Flashcards
BIOMECHANICAL PRINCIPLES
BIOMECHANICAL PRINCIPLES
What is Newton’s 1st Law?
Law of Inertia
-A body remains at rest or at a constant linear or angular velocity except when compelled by an external force to change its state.
What is inertia?
Amount of energy required to alter the velocity of a body.
What is inertia directly related to?
Directly proportional to mass.
Where is the center of mass typically located on the human body?
Just anterior to 2nd sacral vertebrae in upright.
What is meant by center of gravity?
Point where effects of gravity are completely balanced.
What is the mass moment of inertia?
- Quantity that indicated resistance to change in angular velocity.
- In layman’s terms, the ability to resist changes in rotational speed about a specific axis.
What is the mass moment of inertia dependent on?
Mass, but also the distribution of that mass with respect to the axis of rotation.
Which is easier to move forward during the swing phase of gait of running, a leg that weighs 40 pounds that is flexed at the knee and hip or a leg that weight 40 pounds that is extended at the hip and knee?
Leg that is flexed at the knee and hip, due to the mass being closer to the axis of rotation.
What is Newtons 2nd Law?
Law of Acceleration
- The linear acceleration of a body is directly proportional to the force causing it, takes place in the same direction in which the force acts, and is inversely proportional to the mass of the body.
- F=ma
- The angular acceleration of a body is directly proportional to the torque causing it, takes place in the same rotary direction in which the torque acts, and is inversely proportional to the mass moment of inertia of the body.
- T=mass moment of inertia (I) * angular acceleration (α)
What is acceleration directly proportional with?
What is angular acceleration directly proportional with?
- force
- torque
What is acceleration inversely proportional to?
What is angular acceleration inversely proportional to?
- mass
- mass moment of inertia
What is newtons 3rd Law?
-For every force, there is an equal and opposite directed force.
What does an electrogoniometer measure?
Measures angles of joints and their ROM.
What does an accelerometer measure?
Measure acceleration of either individual segment or whole body.
What is a force plate used for?
Measure the ground reaction forces generated by a body.
INTRO TO KINESIOLOGY
INTRO TO KINESIOLOGY
What is kinesiology?
Study of movement
What are the three cardinal planes of osteokinematics and the motions that occur in each of these planes?
Sagittal
- Flexion and Extension
- Dorsiflexion and Plantarflexion
- Forward and Backward Bending
Frontal (Coronal)
- Abduction and Adduction
- Lateral Flexion
- Radial and Ulnar Deviation
- Inversion and Eversion
Horizontal (Transverse)
- Internal and External Rotation
- Axial Rotation
What is Degree of Freedon (DOF)?
Number of independent directions of movevment allowed at a joint.
What are the degrees of freedom of a uniaxial, biaxial, and triaxial joint?
Uniaxial= 1 DOF Biaxial= 2 DOF Triaxial= 3 DOF
What is the difference between a closed kinetic chain and an open kinetic chain?
CKC- Chain in which the distal segment is fixed and the proximal segment is free to move.
OKC- Chain in which the proximal segment is fixed and the distal segment is free to move.
Does osteokinematics or arthrokinematics describe the motion we visualize with movement?
Osteokinematics
Does osteokinematics or arthrokinematics describe the motion that occurs between the joint surfaces that you cannot visually see when observing?
Arthrokinematics
Describe the convex-concave rule.
- If the moving part is convex, the glide will be opposite of the roll.
- If the moving part is concave, the glide will be in the same direction of the roll.
Describe the direction of the roll and glide for glenohumeral flexion.
- Arm is moving anteriorly
- Roll is moving anteriorly
- Glide is moving posteriorly
Describe the direction of the roll and glide for glenohumeral extension.
- Arm is moving posteriorly
- Roll is occuring posteriorly
- Glide is occuring anteriorly
Describe the direction of the roll and glide for glenohumeral abduction.
- Arm is moving laterally
- Roll is moving superiorly
- Glide is moving inferiorly
Describe the direction of the roll and glide for glenohumeral adduction.
- Arm is moving medial
- Roll is moving inferiorly
- Glide is moving superiorly
Describe the direction of the roll and glide for tibiofemoral flexion.
- Leg is moving posteriorly
- Roll is moving posteriorly
- Glide is moving posteriorly
Describe the direction of the roll and glide for tibiofemoral extension.
- Leg is moving anteriorly
- Roll is moving anteriorly
- Glide is moving anteriorly
What is the third but less common movement in arthrokinematics?
Spin
What is excessive joint play and what may it be a result of?
- hypermobility
- can occur from ligamentous injury or abnormal laxity
The direction of roll and spin is typically in the _______ direction as osteokinematics.
same
Convex on concave- glide and osteokinematics occur in ________ direction.
Concave on convex- glide and osteokinematics occur in _________ direction.
- opposite
- same
If we are performing shoulder abduction, and the arthrokinematics roll but do not glide, what could happen?
Cause impingement in subacromial space.
What is the difference between a loose-packed position (LPP) and a closed-packed position?
- CPP is the point where there is maximal congruency between the bones at the joint. In this position most ligaments and capsules are taut, thus resulting in a stable joint.
- LPP is the point where there is the least congruency between the bones at the joint. In this position the ligaments and capsules are on slack resulting in allowance for increased accessory movements.
Do we perform joint mobilizations in the closed-packed or loose-packed position and why?
Loose-packed position (LPP)
-This is where the joint will be the most mobile.
What is the difference between kinematics and kinetics?
- Kinematics involves looking at the motions without thinking of forces acting on the motions.
- Kinetics is involving the forces and torques acting and thus taking into account mass.
What are the 6 main forces applied to the musculoskeletal system?
Describe them.
- Tension-pulling bone apart
- Compression-pushing bone together
- Bending-…bending
- Shear-force is applied as 2 surfaces move across one another
- Tension-twisting motion
- Combined loading-tension and compression
T or F
After strain in the elastic region is removed from a tissue it results in permanent change. Explain.
False, the point in which permanent change occurs is called the plastic region.
What happens to tissue stretched in the elastic region?
It will return to its original length.
What is the beginning of the plastic region?
What is the ending of the plastic region?
Explain both.
- Yield point- this is where elongation occurs beyond a physiological range
- Ultimate failure point- point where tissue is partially or completely seperated
What is the area that must be drawn taut before tension is measured called?
Toe region
What is viscoelasticity?
Viscocity=resistance to flow
Elasticity=ability to return to original length
Tissues with high viscocity have a _____ resistance to deformation.
high
What is creep and what tissues is creep a part of in the body?
- Creep is the progressive strain of a material when exposed to a constant load over time.
- Connective tissue
What is a good way to visualize creep?
Tree branch with a weight put on the end will eventually start to pull the branch down even though the weight stays the same.
Internal forces can be both _______ and ________.
active and passive
What are some examples of active vs passive forces produced within the body?
Active- muscle
Passive- connective tissue such as ligament or joint capsule
What are examples of external forces?
Things such as gravity or weights
What is the moment (lever) arm?
Perpendicular distance between axis of rotation of the joint and the force being applied
What is the difference between internal and external torque?
- Internal torque is a product of internal force and internal moment arm.
- External torque is a product of the external force and external moment arm.
If internal torque is greater than external torque what happens?
Concentric contraction
If internal torque is less than external torque what happens?
Eccentric contraction
If internal and external torque are equal what happens?
Isometric contraction
In MMT, the clinician is providing an ______ torque to assess the strength of the individual’s ability to produce an _______ torque.
- external
- internal
What is meant when we talk about the classes of levers?
Where the axis is in regards to the force (muscle) and resistance (external)
In a first class lever, where does the axis of rotation, internal torque, and external torque sit in relationship to one another?
Axis of rotation is between internal torque (Force) and external torque (Resistance)
In a second class lever, where does the axis of rotation, internal torque, and external torque sit in relationship to one another?
Axis of rotation is at one end, resistance in the middle, and force at the other end
In a third class lever, where does the axis of rotation, internal torque, and external torque sit in relationship to one another?
Axis of rotation at one end, force in the middle, and resistance at the other end
What lever arm is the most common in the human body?
3rd class lever
BASIC STRUCTURE AND FUNCTION OF HUMAN JOINTS
BASIC STRUCTURE AND FUNCTION OF HUMAN JOINTS
What are the 2 joint types?
- Synarthrosis
- Diarthrosis (Synovial)
Which type of joint allows for essentially no movement?
Synarthrosis
Synarthrosis can be further broken down into what 2 types of joints?
- Fibrous
- Cartilaginous
What are the 7 elemental structures that are always present in diarthrodial (synovial) joints?
- synovial fluid
- articular cartilage
- joint capsule
- synovial membrane
- ligaments
- blood vessels
- sensory nerves
What are the 7 types of synovial joints and what are examples of each?
- Hinge- humeroulnar joint
- Pivot- humeroradial joint
- Ellipsoid- radiocarpal joint
- Ball and Socket- GH and hip joint
- Plane- intercarpal or intertarsal joint
- Saddle- carpometacarpal joint of thumb
- Condyloid- metacarpophalangeal joint
T or F
The axis of rotation at your joints is a fixed point.
False, they are rarely fixed.
What does connective tissue form?
- capsules
- ligaments
- tendons
- articular cartilage
- fibrocartilage
What are the main components of connective tissue?
Fibrous proteins -Collagen (type I and II) -Elastin Ground Substance -Glycosaminoglycans (GAGs) -Water -Solutes Cells -Fibroblasts -Chondrocytes
What are the three types of periarticular connective tissue?
- Dense Connective Tissue
- Articular Cartilage
- Fibrocartilage
What is included in dense connective tissue?
- ligaments
- fibrous layer of the joint capsule
- tendons
Dense connective tissue has limited what?
blood supply
What is the primary function of dense connective tissue?
resist tension
Dense connective tissue can be classified as ________ and _________.
Regular and irregular
What is the difference between regular and irregular dense connective tissue?
- Irregular has a more haphazard orientation of collagen and is suited to resist tensile forces in multiple directions.
- Regular has near parallel orientation of collagen and functions most effectively when stretched parallel to long axis of ligament.
A _______ is an example of tissue made up of mostly irregular dense connective tissue.
joint capsule
A _______ is an example of tissue made up of mostly regular dense connective tissue.
ligament or tendon
Why is the rate of repair slow or nonexistent in dense connective tissue?
Limited blood supply
Are tendons or ligaments laid out more parallel?
tendons (ligaments are nearly parallel)
What is the primary function of articular cartilage?
Distribute and absorb joint forces and reduce joint friction.
Articular cartilage is thicker in areas of what?
high compression
Articular (hyaline) cartilage is avascular and aneural, meaning what?
- doesn’t have the ability to repair itself
- don’t feel it wearing down
How does articular (hyaline) cartilage recieve nutrients?
compression
Fibrocartilage is a mixture of what?
dense and articular cartilage
What is included in fibrocartilage?
- menisci
- labrum
- discs
What is the primary function of fibrocartilage?
Supports and mechanically stabilizes joints, dissipates loads across multiple planes and guides complex arthrokinematics
Fibrocartilage is also anueral and has limited ____________.
blood supply (outer rim of some fibrocartilage do have direct blood supply
What is the primary function of bone?
Rigid support to the body and systems of levers for muscles.
Are bones vascularized and innervated?
Yes, they are richly vascularized and innervated.
What is the concept behind Wolff’s law?
Bone is laid down in areas of high stress and reabsorbed in areas of low stress.
What impact does immobilization have on connective tissue?
Rapid loss of strength occurs with prolonged reduced loading and recovery is slower.
MUSCLE STRUCTURE AND FUNCTION
MUSCLE STRUCTURE AND FUNCTION
Muscles do not know ______, they simply ________. Each end of the muscle moves toward the ________.
- direction
- contract
- center
What is the fundamental unit within muscle fiber?
Sarcomere
What are the two types of contractile proteins that make up a muscle?
- Actin
- Myosin
What are the two non-contractile proteins that support the structure of the muscle fiber?
- Titin
- Desmin
What is the function of titin?
provides passive tension
What is the function of desmin?
stabilizes alignment of adjacent sarcomeres
Muscles also consist of collagen and elastin, which do what?
provide support and elasticity to muscles
List the levels of a muscle.
- muscle belly surrounded by epimysium
- seperated into fascicles surrounded by perimysium
- muscle fiber surrounded by endomysium
- myofibril
- myofilament
T or F
Fusiform muscles are longer and therefore generally able to generate more force when compared to pennate muscles.
False, they perform quick and wide ROM but have generally small force production compared to pennate muscles.
- Fusiform muscles have ______ fibers, are ______, and have ________ ROM potential.
- Pennate muscles have _______ fibers, are _________, have _____ fibers per given area, and have a ________ ROM.
- parallel
- longer
- greater
- oblique
- shorter
- more
- smaller
What is an agonist, antagonist, and synergist?
Agonist
-the muscle most directly related to initiation and execution of a particular movement
Antagonist
-has an opposite action of a particular agonist
Synergist
-muscles that cooperate during the execution of a particular movement
The agonist for elbow extension is _______, the antagonist for elbow extension is __________.
- triceps
- biceps
What is a force couple?
Formed when 2 or more muscles simultaneously produce force in different linear directions but produce torque in the same direction.
What is an example of a force couple?
Anterior tilt with the erector spinae muscles and the iliopsoas/sartorious muscles.
What are the 3 types of contractions?
- Isotonic (Concentric and Eccentric)
- Isometric
- Isokinetic
What is an isotonic contraction?
When a muscle contract and the length of the muscle changes
What is an isometric contraction?
When a muscle produces a force without changing the length of the muscle
What is an isokinetic contraction?
Resistance, but speed of the contraction stays the same
Isometric can also help to provide an ________ effect.
Analgesic
_________ type of muscle contraction places the most stress on the muscle and tendon.
Eccentric
What is tension and what are the two types of tension?
- force built up within a muscle
- active tension= comes from contractile units
- passive tension= stretching builds passive tension
What is total tension?
combination of active and passive tension
What is tone?
slight tension in muscle at all times, state of readiness
We feel passive tension when a _______ is placed on the connective tissue.
stretch
Passive tension is attributed to elastic forces produced by non-contractile elements such as what?
- ligaments
- joint capsules
What is generating active force?
muscle
Our ideal resting length is the area in the ROM of a muscle is one in which the muscle has the _________ number of crossbridges.
greatest
Why is active tension difficult to generate with the muscle shortened?
too much actin-myosin overlap
Why is active tension difficult to generate with the muscle lengthened?
not as many actin-myosin crossbridges
Putting a quick stretch on a muscle just prior to contraction will create the potential for _______ force production.
greater
Passive insufficiency and active insufficiency are concepts only of ___ joint muscles.
two
_______ insufficiency is the limitation in ROM of a muscle when the muscle is placed on stretch at both joints it crosses.
Passive
______ insufficiency is the limitation in ability to produce force when a muscle is actively contracting at both joints it crosses.
Active
What is a tenodesis grasp?
When a person extends their wrist back to allow the fingers to flex and grasp items
The ______ the load, the ________ the speed of a concentric contraction.
- greater
- slower
The _______ the load, the _________ the speed of a eccentric contraction
- greater
- greater
When attempting to stretch a one joint muscle, you must be aware that you may need to place the two joint muscle on ________ in order to maximize the stretch at the one joint muscle.
slack
