PPT2 – Articular System (PDF)

2/21/2024 Arthrokinematics Muscular System © Stanbridge University 2024 1  2/21/2024 © Stanbridge University 2024 2 ...

2/21/2024 Arthrokinematics Muscular System © Stanbridge University 2024 1  2/21/2024 © Stanbridge University 2024 2  2/21/2024  Define open (OKC) and closed chain (CKC) movements  Review advantages and disadvantages of open and closed chain motions  Define arthrokinematic motion and types of motion occurring at the joint surface  Discuss how the shape of the joint surfaces' influences motion  Present the concave/ convex rule of motion  Describe accessory motion and present different types of this motion  Describe joint congruency and define the open and close pack positions of joints © Stanbridge University 2024 3  2/21/2024  “Consists of a series of rigid links connected in such a way as to allow motion”  Since these links are connected, a movement of one link causes motion at other links in a predictable way  Closed vs. open kinetic chains © Stanbridge University 2024 4  2/21/2024  Requires the distal segment to be fixed and the proximal segment to move ◦ If the distal segment is fixed, the whole limb is fixed, i.e. foot is fixed so ankle, knee and hip will all be moving in closed chain © 2011 by F. A. Davis Company © Stanbridge University 2024 5  2/21/2024  The distal segment is free to move while the proximal segment remains stationary © 2011 by F. A. Davis Company © Stanbridge University 2024 6  2/21/2024  There are many joints that do both open and closed chain activities regularly (hip/knee/ankle/foot)  Its important to be able to visualize both ways a muscle can pull on the body © Stanbridge University 2024 7  2/21/2024 OPEN CHAIN (OKC) CLOSED CHAIN (CKC)  Distal segment moves in space  Distal segment remains in contact with support surface  Independent joint movement;  Interdependent joint no predictable joint motion in movements; relatively adjacent joints predictable movement patterns in adjacent joints  Movement of body segments  Movement of body segments only distal to the moving joint may occur distal and/or proximal to the moving joint © Stanbridge University 2024 8  2/21/2024 OPEN CHAIN (OKC) CLOSED CHAIN (CKC)  Muscle activation occurs mainly  Muscle activation occurs in in the prime movers and is multiple muscle groups, both isolated to muscles of the distal and proximal to the moving moving joint joint  Typically performed in NWB  Typically, but not always positions performed in WB positions  External stabilization (manually  Internal stabilization by means of or with equipment) usually muscle action, jt. compression required, especially if lifting and congruency, and postural heavy loads control © Stanbridge University 2024 9  2/21/2024 Osteokinematic motion = Joint motion (bone motion)  Describes the motions of the bones moving on the bones  i.e. flexion/extension, abduction/adduction, etc. Arthrokinematic motion = Joint surface motion  Describes the motions that occurs between adjoining joint surfaces  Must accompany osteokinematic motions for normal motion to occur  NOT under voluntary control © Stanbridge University 2024 10  2/21/2024  Three types: ◦ Roll ◦ Glide ◦ Spin  Most joint movements involve a combination of all three of these types of motion © Stanbridge University 2024 11  2/21/2024  Roll ◦ The rolling of one joint surface on another ◦ New points on each surface come into contact throughout the motion ◦ EX: Ball rolling across the ground © 2011 by F. A. Davis Company © Stanbridge University 2024 12  2/21/2024  Glide ◦ Linear movement of a joint surface parallel to the plane of the adjoining joint surface ◦ One point on a joint surface contacts new points on the adjacent surface ◦ EX: One point on an ice skater’s blade gliding across many points on the ice’s surface © 2011 by F. A. Davis Company © Stanbridge University 2024 13  2/21/2024  Spin ◦ Rotation of the movable joint surface on the fixed adjacent surface ◦ Same point on each joint surface remains in contact ◦ Roll and glide in perfect balance ◦ EX: spinning top ◦ This course will focus on roll and glide © 2011 by F. A. Davis Company © Stanbridge University 2024 14  2/21/2024  Shape of the joint surfaces determine the motion that occur at the joint  Shape determines motion © 2011 by F. A. Davis Company © Stanbridge University 2024 15  2/21/2024 © 2011 by F. A. Davis Company ◦ Ovoid joint  Has two bones forming a convex- concave relationship  Most synovial joints are ovoid ◦ Sellar (saddle-shaped) joint  Each joint surface is concave in one direction and convex in another © Stanbridge University 2024 16  2/21/2024  Roll, spin, and glide must occur together to allow for normal movement  Example: Sit to stand movement  Femur would roll off tibia as person raised up from the chair and moved into knee extension if rolling occurred in isolation; posterior GLIDE of femur on tibia allows joint surfaces to remain more congruent  Spin component necessary during last few degrees of knee extension © 2011 by F. A. Davis Company © Stanbridge University 2024 17  2/21/2024  To analyze the link between osteokinematic motion and arthrokinematic motion for a given joint, observe the motion occurring in two locations: 1. Distal/opposite end of the moving bone (osteokinematics) Determine if the motion is open or closed kinetic chain 2. Joint surface of the moving bone (arthrokinematics) Determine if the surface that is moving concave or convex © Stanbridge University 2024 18  2/21/2024  Expression of the relationship between osteokinematics and arthrokinematics for a given movement  Describes how the differences in bone shape requires joint surfaces to move in a specific way during joint movement  Therefore, knowledge of anatomy will be critical to understanding joint movement  Also can be called concave-convex rule © Stanbridge University 2024 19  2/21/2024 “A concave joint surface will ROLL and GLIDE on a fixed convex surface in the same direction as the distal end of the moving bone” (concave = same) © 2011 by F. A. Davis Company © Stanbridge University 2024 20  2/21/2024 “A concave joint surface will ROLL and Application Example: GLIDE on a fixed convex surface in the Open chain MCP jt. extension: concave prox. same direction as the distal end of the moving bone” phalanx moving on fixed convex metacarpal  Always start from anatomical position:  Distal end of moving bone (prox. phalanx) moves posterior during extension  Joint surface of moving bone is concave  According to the rule: roll and glide are posterior © 2011 by F. A. Davis Company © Stanbridge University 2024 21  2/21/2024 “A convex joint surface moving on a fixed concave surface will ROLL in the same direction and GLIDE in the opposite direction as the distal end of the moving body segment” © 2011 by F. A. Davis Company © Stanbridge University 2024 22  2/21/2024 “A convex joint surface moving on a fixed Example: concave surface will ROLL in the same Open chain glenohumeral abduction: direction and GLIDE in the opposite direction as the moving body segment” convex humeral head moving on fixed concave glenoid fossa of the scapula  Always start from anatomical position: humerus moves superior during abduction Joint surface of moving bone is convex Therefore, according to the rule: roll is superior and glide is inferior © 2011 by F. A. Davis Company © Stanbridge University 2024 23  2/21/2024  Roll is always in the same direction as the moving bone’s motion, whether the moving bone is convex or concave ◦ Roll is always the same for a given osteokinematic motion, i.e. shoulder flexion will always be an anterior roll regardless of open or closed chain  Glide: -If convex jt. surface moving the glide is in opposite direction Kisner and Colby,2018 -If concave jt. surface moving the glide is in same direction © Stanbridge University 2024 24  2/21/2024 © Stanbridge University 2024 25  2/21/2024 Motion: Shoulder flexion Step one: determine if it is an open or closed chain motion  Example: reaching into a cupboard in front of you is open chain GH flexion Step two: Identify the direction the bone is rolling (look at the distal end of the bone)  OKC shoulder flexion- the distal humerus is rolling anteriorly Step three: apply the rule: convex humerus is moving on the concave glenoid (glide opposite of the role)  The glide is posterior  Final answer: anterior roll, posterior glide © Stanbridge University 2024 26  2/21/2024 Motion: Shoulder Flexion Step one: determine if it is an open or closed chain motion  Example: pushing up out of a push up is closed chain shoulder flexion Step two: Identify the direction the bone is rolling: the direction of the ROLL never changes from open to closed chain, but which bone is rolling does  CKC shoulder flexion- the scapula is rolling anteriorly on the fixed humerus Step three: apply the rule: concave scapula is rolling anteriorly on the convex humerus (same direction)  The glide is anterior  Final Answer: anterior roll, anterior glide © Stanbridge University 2024 27  2/21/2024  Motion: Shoulder External Rotation (ER) Step one: determine if it is an open or closed chain motion  Example: reaching back to prepare to throw a ball (cocking phase): OKC ER Step two: Identify the direction the bone is rolling (look at the distal end of the bone)  OKC ER- the distal humerus is rolling posteriorly Step three: apply the rule: convex humerus is moving on the concave glenoid (glide opposite of the role)  The glide is anteriorly  Final answer: posterior toll, anterior glide © Stanbridge University 2024 28  2/21/2024 What about the analysis of a more complicated motion, such as the tri-planar multi- joint motion of PRONATION In this case, you break down each motion individually (we will just analyze the talocrural joint and subtalar joint motions) OKC Pronation: Talocrural DF: talus is rolling anteriorly, it is convex shape, so the glide is posterior Subtalar eversion: posterior weight bearing surface of the calcaneus is rolling laterally and is convex shape, resulting in a medial glide CKC Pronation: Talocrural DF: now the tibia is moving anteriorly, it is concave shape, so the glide is anterior Subtalar eversion: The talus is moving on the fixed calcaneus it is rolling laterally and is concave shape, resulting in a lateral glide © Stanbridge University 2024 29  2/21/2024  With excessive overhead throwing, with great force, the UE is placed in end range external rotation (at 90 degrees abduction)  This will stretch out the joint capsule  What injury does this place the glenohumeral joint in risk of?  Consider arthrokinematics © Stanbridge University 2024 30  2/21/2024 Terminology ◦ Component movements:  “Motions that accompany active motion but are not under voluntary control”  Motion cannot be done independently but must occur for normal joint motion to occur  EX: external rotation of the tibia on femur with knee extension (known as the screw home mechanism); rotation of thumb that occurs with opposition © Stanbridge University 2024 31  2/21/2024 Terminology ▪ Joint play: Passive arthrokinematic movements that occur between joint surfaces when an external force creates passive motion at a joint; therapists can assess the amount of passive accessory motion at a joint Kisner and Colby, 2018 © Stanbridge University 2024 32  2/21/2024 Joint play Joint play is necessary for normal joint functioning throughout the osteokinematic ROM and helps allow for roll, glide, and spin to occur When joint play is limited, reduced osteokinematic motion typically occurs: therapist might perform joint mobilization to improve mobility © Stanbridge University 2024 33  2/21/2024  Three main types of forces used to create movement between joint surfaces: ◦ Traction force: causes joint surfaces to move away from each other ◦ Shear force: glide that occurs when joint surfaces move parallel to one another ◦ Approximation force = causes joint compression (joint surfaces move toward each other)  Bending and torsional forces: result from a combination of traction, shear, and approximation forces © Stanbridge University 2024 34  2/21/2024 Traction, gliding (shear force), bending, torsional forces used to assist in restoring joint mobility Kisner and Colby, 2018 Approximation used to help promote joint stability and increase proprioceptive input © Stanbridge University 2024 35  2/21/2024  Traction ◦ Occurs when external force is exerted on joint causing the joint surfaces to pull apart ◦ EX: Carrying a heavy suitcase; hanging from a pull-up bar; traction during © 2011 by F. A. Davis Company joint mobilization traction of tibiofemoral joint © Stanbridge University 2024 36  2/21/2024 Types of Traction: 1. Distraction: separation of joint surface at Distraction of GH jt. right angles 2. Long axis traction: traction force is applied to long axis of bone Kisner and Colby, 2018 Long axis traction of GH jt. © Stanbridge University 2024 37  2/21/2024  Approximation ◦ aka ‘compression’ ◦ Occurs when external force is exerted on a joint, causing the joint surface to be pushed closer © 2011 by F. A. Davis Company together ◦ EX: Push up; joint approximation techniques © Stanbridge University 2024 38  2/21/2024  Shear ◦ Shear forces occur parallel to the joint surface ◦ Results in glide motion at joint ◦ Cause joint surfaces to move parallel to and in opposite directions from each other ◦ EX: Joint mobilization © 2011 by F. A. Davis Company © Stanbridge University 2024 39  2/21/2024  Bending ◦ Occurs when an other-than-vertical force is applied, resulting in a compression on the concave side & distraction on the convex side  Torsion (aka ‘Rotary’) ◦ Involve a twisting motion ◦ One force is trying to turn one end or part © 2011 by F. A. Davis Company about a longitudinal axis while the other force is fixed or turning in the opposite direction © Stanbridge University 2024 40  2/21/2024  Close-packed  Open-packed ◦ Joint surfaces: ◦ Joint surfaces:  Have maximum contact with one another  Maximally incongruent (aka ‘congruent’) ◦ Parts of the capsule and supporting ligaments  Are tightly compressed are lax  Are difficult to distract or separate ◦ aka ‘resting position’ ◦ Ligaments & capsule holding joint together ◦ Best initial position for joint mobilization are taut technique to be applied ◦ Usually occurs at one extreme of the ROM ◦ Position allows for certain “accessory motions” (aka ‘joint play’) © Stanbridge University 2024 41  2/21/2024 Joint Close-packed position Open-packed position 55° ABD, Glenohumeral Maximal ABD, max. ER 30° Horizontal. ADD, slight ER Full elbow EXT, full radioulnar Humeroulnar 70° elbow FLEX, 10° supination supination Slight FLEX IP joints- fingers Maximal EXT Talocrural Maximal DF 10° PF See handout on Edverum that includes all the joints © Stanbridge University 2024 42  2/21/2024 Part 2: identify open vs closed movement and apply arthrokinematic rules © Stanbridge University 2024 43  2/21/2024 Stand on your left leg. Lift your right leg off the floor so your right femoroacetabular (hip) joint flexes Is the femur moving on the acetabulum or is the acetabulum moving on the femur? A)Acetabulum on femur B)Femur on acetabulum Is the proximal end of the femur concave or convex? A) Concave B) Convex Does the acetabulum have a concave or convex joint surface? A) Concave B) Convex © Stanbridge University 2024 44  2/21/2024 With a partner, perform the following action and answers the following questions. Stand on your left leg. Lift your right leg off the floor so your right hip joint flexes into a marching position. Which bone is moving? What is the shape of the end of the moving bone? Is the right hip movement considered open or closed chain? What direction is the distal end of that moving bone going when starting from anatomical position? Based on the concave-convex rule, what is the direction of the roll? Based on the concave-convex rule, what is the direction of the glide? © Stanbridge University 2024 45  2/21/2024 © Stanbridge University 2024 46  2/21/2024 At the completion of this lecture, the students will be able to: – Identify muscular anatomy and function of the muscular system – Define the terms origin, insertion, and muscle action: concentric/eccentric and open/closed chain – Differentiate between the characteristics of muscle tissue – Define the term length-tension relationship as it applies to muscles and discuss relevant characteristics of active insufficiency, passive insufficiency, stretching, and tenodesis – Identify the three types of muscle contraction (ISOM, ISOT, ISOK) and be able to demonstrate or provide examples of each – Define the four roles of muscles and identify the role of various muscle groups for a given gross motor activity – Explain the clinical significance of “angle of pull” for a specific muscle or muscle group – Differentiate between closed and open kinetic chain activities and demonstrate or describe examples of each type © Stanbridge University 2024 47  2/21/2024  Muscles are attached to bones via tendons and cross at least one joint, so when a muscle contracts, one end of the joint moves toward the other  Origin (proximal insertion) ◦ Located on the more stable bone ◦ Typically, closer to the axial skeleton  Insertion (distal insertion) ◦ Located on the more movable bone ◦ Insertion moves toward the origin when the muscle contracts © 2011 by F. A. Davis Company © Stanbridge University 2024 48  2/21/2024 Hands fixed on bar during a “pull-up”  What if the more movable end exercise becomes less movable?  i.e. stabilized by external force (pull-up bar) or another muscle contraction  Muscle (biceps brachii) may perform same action (elbow flexion) but with the origin moving toward the insertion (closed chain) © Stanbridge University 2024 49  2/21/2024  Muscle fibers are arranged within the muscle in a direction that is either parallel or oblique to the muscle’s long axis  Parallel muscle fibers tend to be longer and thus have a greater potential for shortening and producing more range of motion  Oblique muscle fibers tend to be shorter but are more numerous per given area than parallel fibers, which means they tend to produce more power © Stanbridge University 2024 50  2/21/2024 © Lippert 2017 © Stanbridge University 2024 51  2/21/2024  PARALLEL FIBER muscles: strap, fusiform rhomboidal (rectangular), or triangular ◦ Strap muscles are long and thin with fibers running the entire length of the muscle ◦ Fusiform muscle has a shape like that of a spindle. It is wider in the middle and tapers at both ends where it attaches to tendons. Most, but not all, fibers run the length of the muscle. The muscle may be any length or size, long to short or large to small ◦ Rhomboidal muscle is four-sided, usually flat, with broad attachments at each end ◦ Triangular muscles are flat and fan-shaped, with fibers radiating from a narrow attachment at one end to a broad attachment at the other © Stanbridge University 2024 52  2/21/2024 OBLIQUE-fibered muscles have a feather arrangement in which a muscle attaches at an oblique angle to its tendon, much like feather tendrils attach to the quill The different types of oblique-fibered muscles are unipennate, bipennate, and multipennate Unipennate muscles look like one side of a feather. There are a series of short fibers attaching diagonally along the length of a central tendon Bipennate muscle pattern looks like that of a common feather. Its fibers are obliquely attached to both sides of a central tendon Multipennate muscles have many tendons with oblique fibers in between © Stanbridge University 2024 53  2/21/2024 Normal muscle length – The length of a muscle when it is not shortened or lengthened-when there are no forces or stresses placed on it Irritability – Ability to respond to a stimulus Contractility – Ability to shorten or contract when it receives adequate stimulation; may result in muscle shortening (concentric), remaining the same length (isometric) or lengthening (eccentric). © Stanbridge University 2024 54  2/21/2024  Extensibility ◦ Ability to stretch or lengthen when a force is applied  Elasticity ◦ Ability to recoil or return to normal resting length when the stretching or shortening force is removed ◦ Low elasticity = ‘plastic’; high elasticity = ‘elastic’  Examples: ◦ Saltwater taffy: very extensible (easy to stretch) but not elastic (does not return to original shape) ◦ Wire spring: less extensibility (requires more force to stretch it) but it is very elastic (goes right back to the starting shape) © Stanbridge University 2024 55  2/21/2024  “Tension” refers to the force built up within a muscle  Stretching a muscle builds up passive tension and involves non-contractile units of muscle  Active tension comes from the contractile units  Total tension of a muscle is a combination of active and passive tension © Stanbridge University 2024 56  2/21/2024  Tone ◦ The slight tension that is present in a muscle at all times, even when the muscle is resting ◦ A state of readiness that allows the muscle to act more easily and quickly when needed ◦ Four (4) categories of muscle tone:  Hypertonia = too much or more than normal  Normotonia = normal  Hypotonia = less than normal  Atonia = no tone © Stanbridge University 2024 57  2/21/2024  Tone ◦ Certain injuries, illnesses or conditions can result in:  Hypertonia: associated with Upper Motor Neuron lesion  i.e. CVA; dementia; Multiple Sclerosis (depending on site of lesion); amyotrophic lateral sclerosis (ALS)  Hypotonia: associated with a Lower Motor Neuron lesion  i.e. Guillain-Barre; polio; ALS  Atonia: aka ‘flaccid’ © Stanbridge University 2024 58  2/21/2024  Muscle is capable of being shortened to approximately ½ of its normal resting length  Muscle can be stretched to about 1.5 times its normal resting length  The distance from maximum elongation to maximum shortening is termed the muscle’s “excursion” © 2011 by F. A. Davis Company © Stanbridge University 2024 59  2/21/2024  Excursion in muscles crossing only one joint (“1 joint muscles”) ◦ In 1-joint muscles, there is usually enough excursion to allow a joint to move through its entire ROM (maximal shortening to maximal lengthening) brachialis: full elbow flexion to full elbow extension Trail Guide, 2015 © Stanbridge University 2024 60  2/21/2024  Excursion in muscles crossing more than one joint: “2 (or more) joint muscles” Muscles crossing multiple joints may not have enough excursion to allow the joint to move through the combined ROM of all the joints that it crosses at the same time i.e. : biceps brachii -maximal shortening: sh. flex., supination, elbow flexion -maximal lengthening: sh. ext., pronation, elbow extension Trail Guide, 2015 © Stanbridge University 2024 61  2/21/2024  One factor that determines the amount of force a muscle can generate is its length  When a muscle is on a slight stretch (but not overstretched), it is said to be at optimal length  Being at optimal length increases the muscle’s force-generating capacity in 2 ways: 1. Maximal # of myosin heads are bound to and pulling on the actin filaments increasing force generation during contraction 2. There is some passive tension in the muscle (stored energy that is built up) © Stanbridge University 2024 62  2/21/2024 “Optimal Passive tension Length” Passive decreases as m. tension over shortens and actin hip filaments Passive approximate tension over knee Actin & myosin positioned for max. binding © Lippert, 2017 © Stanbridge University 2024 63  2/21/2024 A muscle contraction is strongest when the muscle is at an optimal length/stretch and quickly loses its power as it shortens Think: Rubber band publiclab.org © Stanbridge University 2024 64  2/21/2024 Contraction force of a muscle is reduced when the muscle is not at optimal length  Too short: actin filaments overlap, reducing available binding sites for myosin heads  Too long (over-stretched): some myosin heads cannot reach a binding site  Therefore, weakness can be a result of the muscle being too short or too long Lippert, 2017 © Stanbridge University 2024 65  2/21/2024  Two-joint muscles have the advantage over one-joint muscles in that they maintain greater contractile force through a wider range  How? By contracting over one joint while being elongated over another & thus maintaining an optimal length- tension relationship © Lippert, 2017 © Stanbridge University 2024 66  2/21/2024 © Lippert 2017 © Stanbridge University 2024 67  2/21/2024  These terms are terms reserved for multi-joint muscles ◦ Passively insufficient: Muscle can’t be elongated any farther ◦ Actively insufficient: Muscle can’t be shortened any farther © Stanbridge University 2024 68  2/21/2024  Active insufficiency ◦ The point at which a muscle cannot shorten any farther ◦ Occurs to the agonist (the muscle that is contracting) ◦ In a two-joint muscle there is “insufficient power” to fully contract (shorten) over both joints at the same time © Lippert 2017 © Stanbridge University 2024 69  2/21/2024  Active insufficiency ◦ EX: Hamstrings: two-joint muscle ◦ Try flexing knee with hip fully extended: can’t fully flex knee - Muscle not capable of shortening that much over both joints at the same time ◦ Versus flexing knee with hip slightly flexed- able to flex knee through greater ROM © Lippert 2017 © Stanbridge University 2024 70  2/21/2024 What is occurring in this photo? © 2011 by F. A. Davis Company © Stanbridge University 2024 71  2/21/2024 Two joint or multi-joint muscles normally like to function in the mid portion of their functional excursion, where a more ideal length-tension relationship exists © Stanbridge University 2024 72  2/21/2024  Passive insufficiency ◦ The point at which a muscle cannot be elongated any farther without damage to its fibers at end of stretch ◦ Occurs to the antagonist (the muscle that is relaxed & on the opposite side of the agonist, which is the contracting muscle) ◦ In a multi-joint muscle, there is “insufficient length” to fully stretch (lengthen) over all joints at the same time © Lippert 2017 © Stanbridge University 2024 73  2/21/2024 Multi-joint muscles must be put on slack when assessing PROM and end feels to avoid ROM limitations due to passive insufficiency. Keep knee flexed If HS lengthened when assessing over the knee in motion at the hip to this position and hip avoid limitation of continues to be motion due to the flexed, HS will limit hamstrings (HS). the amount of ROM available at the hip. © Stanbridge University 2024 74  2/21/2024 Passive insufficiency can be helpful is some patient populations Tenodesis: functional use ◦ Can be used to accomplish some degree of passive insufficiency of opening and closing of the hand in those that don’t have voluntary ability to open and close the fingers ◦ Multi-joint muscles do not have sufficient length to be stretched over all joints that they cross at the same time Lippert, 2017 →Therefore, as wrist extends, fingers flex, allowing gripping to occur © Stanbridge University 2024 75  2/21/2024 © Lippert 2017 © Stanbridge University 2024 76  2/21/2024  To maintain ROM, segments must move through their available range periodically  Decreased ROM can be caused by factors such as: ◦ Systemic pathologies ◦ Joint contractures ◦ Neurological changes ◦ Muscular diseases ◦ Immobilization/ Inactivity of that segment  Stretching: used to regain normal resting length of a muscle © Stanbridge University 2024 77  2/21/2024  Multi-joint muscles: must be placed in position that will stretch the muscle over all joints at the same time ◦ Hamstrings (HS) as a group extend the hip and flex the knee ◦ Therefore, to stretch, need to flex the hip to stretch HS over the hip jt. & then extend the knee to stretch HS over the knee jt. © Stanbridge University 2024 78  2/21/2024 Single joint muscles: To stretch a 1-joint muscle, must put any multi-joint muscles that cross the same joint on slack Example: ◦ To stretch the soleus (1-jt. m.), flex the knee to put the gastrocnemius(2 jt. m.) on slack © 2011 by F. A. Davis Company © Stanbridge University 2024 79  2/21/2024 Lippert, 2017 © Stanbridge University 2024 80  2/21/2024 ISOTONIC: Force production resulting in movement of the joint; two types: ◦ Concentric: shortening of a muscle (O and I get closer together, making the joint angle smaller) as an external load (weight, manual resistance, gravity, etc.) is overcome ◦ Eccentric: lengthening of a muscle (O and I get further apart, increasing the joint angle); used to decelerate movement caused by gravity or external load; muscle is returning to resting position from a shortened position © Stanbridge University 2024 81  2/21/2024 ISOMETRIC: static exercise; force production without joint motion. i.e. patient flexing elbow against resistance from the therapist and joint angle is not changing ISOKINETIC: Velocity of muscle shortening or lengthening is pre-determined and held constant by arate-limiting device Kisner and Colby 2018 © Stanbridge University 2024 82  2/21/2024 Also called a “gravity-eliminated position” A supported position or plane in which the effect of gravity is absorbed or neutralized May be used if a muscle is too weak to move against gravity Example: Elbow flexion in side-lying (across gravity) versus elbow flexion in standing (against gravity) © Stanbridge University 2024 83  2/21/2024  Agonist or “prime mover” ◦ A muscle or muscle group that causes the motion  Accessory muscle (aka “assisting mover”) ◦ A muscle that is not as effective but does assist in providing the desired motion or to maintain the desired direction © Stanbridge University 2024 84  2/21/2024  Antagonist ◦ A muscle that performs the opposite motion of the agonist ◦ Has potential to oppose the agonist, but is usually relaxed if the agonist is working  Co-contraction ◦ Occurs when agonist and antagonist contract at the same time (usually creates an isometric situation) © Stanbridge University 2024 85  2/21/2024  Stabilizer ◦ A muscle or muscle group that supports, or makes firm, a part and allows the agonist to work more efficiently ◦ EX: serratus anterior stabilizes the scapula against the thorax so the humerus can move efficiently on the scapula ◦ EX: push-up: elbow extensors are the agonists, but the abdominals stabilize the trunk to keep the trunk straight while the body moves © Stanbridge University 2024 86  2/21/2024  Synergist ◦ A muscle that works with one or more other muscles to enhance a particular motion ◦ EX: During hip flexion, hip flexors and some adductors are active as well to increase the power and control the trajectory of the limb © Stanbridge University 2024 87  2/21/2024  The role that a muscle will play in a specific joint motion is determined by factors including: ◦ Size ◦ Angle of pull ◦ The joint motions possible (degrees of freedom) ◦ Location of the muscle in relation to the joint axis ◦ Desired movement outcome © Stanbridge University 2024 88  2/21/2024  Infraspinatus and teres minor are both prime movers for shoulder external rotation  HOWEVER, the size difference helps determine which of the two “does it better”  Based on the anatomy: Infraspinatus © 2011 by F. A. Davis Company © Stanbridge University 2024 89  2/21/2024 Greater horizonal line of pull will adduct or abduct the scapula © Lippert 2017 © Stanbridge University 2024 90  2/21/2024 Infraspinatus and Teres minor are better external rotators (prime movers) than supraspinatus due to their location relative to the joint axis of rotation for ER © Stanbridge University 2024 © Lippert 2017 91  2/21/2024 The flexor carpi radialis performs wrist flexion & radial deviation and the flexor carpi ulnaris performs wrist flexion & ulnar deviation. During which radiocarpal wrist motion do the two muscles (FCR & FCU) act as agonists? A) Extension B) Flexion C) Radial deviation D) Ulnar deviation © Stanbridge University 2024 92  2/21/2024 The flexor carpi radialis performs wrist flexion & radial deviation and the flexor carpi ulnaris performs wrist flexion & ulnar deviation. During which radiocarpal motions do the two muscles (FCR & FCU) act as antagonists to each other? A) Flexion/Extension B) Radial/Ulnar deviation © Stanbridge University 2024 93  2/21/2024 Sitting with a weight in your left hand, forearm and shoulder in neutral rotation, and elbow extended, slowly move your hand out to the side to shoulder level. What muscle group and type of muscle contraction is occurring at the shoulder as you raise your arm out to the side? A) Shoulder adductors; concentric contraction B) Shoulder abductors; eccentric contraction C) Shoulder adductors; eccentric contraction D) Shoulder abductors; concentric contraction © Stanbridge University 2024 94  2/21/2024 Using the same scenario as the previous slide, is this an open or closed chain exercise? A) Open B) Closed What position would you need to be in to complete this same motion in an across-gravity position? A) Left sidelying B) Right sidelying C) Sitting D) Supine © Stanbridge University 2024 95  2/21/2024 Sitting with a weight in your left hand, forearm and shoulder in neutral rotation, and elbow extended, slowly move your hand out to the side to shoulder level. Then lower your arm back to the start position. What muscle group and type of muscle contraction is occurring at the shoulder as you lower your arm back to the starting position? A) Shoulder adductors; eccentric contraction B) Shoulder abductors; eccentric contraction C) Shoulder adductors; concentric contraction D) Shoulder abductors; concentric contraction © Stanbridge University 2024 96  2/21/2024 This picture shows a hamstring muscle that cannot be elongated any further. This is an example of what? A) active insufficiency B) passive insufficiency © Kisner and Colby, 2018 © Stanbridge University 2024 97  2/21/2024 Part 3: what muscles are working, and what type of contraction is occurring © Stanbridge University 2024 98  2/21/2024  Determine what motions are occurring when a person moves from a sitting position into standing at the hip, knee and ankle joints.  Consider the idea of “relative motion”- meaning the patient might be moving from a flexed position towards extension but not reach end range  Once you know the motion that is occurring, you need to determine what muscles were the prime movers to create that motion at the 3 joints in the CKC chain  Lastly, determine what type of contraction (isometric, concentric or eccentric) is occurring in those prime moves to create the motion © Stanbridge University 2024 99  2/21/2024  Review the same steps for motion in the opposite direction  How does the motion change at the joints  Are the same of different muscles working?  What type of contraction occurs when lowering to the chair © Stanbridge University 2024 100  2/21/2024 Assess how the 3 main joints of the extremity are working at the same time  Reaching with a UE into a cupboard in front of you  Opening a door towards you with the UE  Using the UE to push out of a wheelchair  Using the UE to lower yourself into a chair  Lifting the LE to step onto a step © Stanbridge University 2024 101