Therapeutic Kinesiology:Musculoskeletal Systems, Palpation, and Body Mechanics

Therapeutic Kinesiology Instructor Manual: Ch04 p.5 TK INSTRUCTOR MANUAL: CHAPTER 4 The Muscular System Chapter manuals include: Objectives Lecture Notes Suggested Classroom and Student Development Activities For other chapter-by-chapter resources, see: Key Term Quizzes Muscle Origin and Insertion Worksheets Muscle OIAs List by Chapter MyTest Test Bank For additional resources see “Teaching Tips and Tools”: 7 research-based learning principles for kinesiology courses in massage 5-step self-directed learning cycle for body mechanics courses Tools that build metacognitive skills: e.g., concept (mind) maps, grading rubrics, and self-assessments inventories OBJECTIVES Define the muscular system and describe its main kinesiological functions. List and describe five types of muscle shapes. Define how a muscle is named and the origin and insertion of a muscle. List and define four properties of muscle tissue. Describe the smallest contractile unit and the overall structure of a muscle. Name and describe the theory that explains muscular contraction. Define a motor unit and the all-or-none law. Define the recruitment process with a single muscle. Define muscle tone. Name the energy source for contraction and two ways that muscles metabolize it. Define and contrast muscle spasms, muscle contractures, and muscle fatigue. List and briefly describe three types of contractile fibers in muscle. Define and describe the myofascial system and the manual techniques that address it. Describe passive tension and active tension. List and define three types of contraction and define the lengthtension relationship. Describe the different functions that a muscle can perform in movement. Define coordination and describe the process of a coordinated movement. Describe the difference between passive and active insufficiency in biarticular muscles. LECTURE NOTES MUSCULAR SYSTEM Approximately 605 skeletal muscles Provide postural support Generate joint motion Look to names for clues about muscle Shape e.g., rhomboidal, rectus, longus Location e.g., superior, inferior Size e.g., maximus, medius, minimus Function e.g., flexors, extensors, adductors Excursion Distance a muscle can lengthen or shorten Determined by shape Muscle attachments Origins Usually most proximal attachment Insertion Usually most distal attachment CONTRACTILE STRUCTURES AND MECHANISMS Four properties of muscle tissue Contractility: Capacity to forcibly shorten with nerve stimulation Extensibility: Capacity to return to normal resting Elasticity: Capacity to be lengthened by outside forces Responsiveness (excitability): Ability to respond to stimuli Muscle fibers (cells) Microfilaments Contractile: Actin and myosin Elastic and supportive: titin Sliding filament theory of muscle contraction Motor nerve stimulates sarcolemma Electrical impulse travels down T-tubules Flood of calcium ions open binding sites Myosin and actin heads bind, pull, release 1 bind, pull, release = 1 muscle twitch Series of twitches produces a contraction Motor units A motor neuron + all fibers it innervates Smallest functional unit in muscle All-or-none law Contract in round-robin order Size of motor unit determines function Small (1050 fibers): Fine motor control Large (1002,000): Strong contraction Frequency of stimulation produces wave summation Contractile strength grows with each twitch Ensures a smooth, continuous contraction When all motor units firing, maximum tension produced Recruitment of motor units A gradual increase in number of motor units firing Also called multiple motor unit summation Small motor units contract before larger units Muscle tone: Involuntary contractions in resting muscle Provides postural support Maintains state of readiness Keeps muscles firm and healthy Muscle contracture and fatigue Contracture: State of continual contraction Occurs when crossbridges fail to unlink Example: writer's cramp Fatigue: Occurs when energy for contraction is depleted. Local fatigue: Preceded by contracture in muscle Central fatigue: From chemical changes in brain and nerves Energy source for muscle contraction Adenosine triphosphate (ATP) Produced in two processes Oxidation (aerobic) Glycolosis (anaerobic) Types of contractile fibers Slow type I fibers: small, weak, fatigue resistant Fast type II fibers: fast, strong, fatigue quickly THE CONTINUITY OF MUSCLE AND FASCIA Myofascial system: muscles + associated fascias Pervasive fascial network of tensional support Wrap and bind muscles, organs, and bones Separate muscle groups into compartments Examples: aponeurosis, retinaculum Adaptations to faulty body positions Adaptively shortened/stretch-weakened muscles Fascial adhesions Manual therapy for myofascial adaptions Deep tissue techniques Use sustained force loading Induce creep: Progressive stretching beyond elastic range Restores mobility Friction techniques: Use on ligaments, tendons, scar tissue MUSCLE TENSION AND CONTRACTILE FORCES Muscle tension produced by Passive: Elasticity in connective tissue Active: Muscular contractions Types of contractions Isometric Isotonic: Concentric and eccentric Lengthtension relationship Length affect amount of tension muscle can generate Length determined by joint position: Outer range Midrange Inner range CHANGING ROLES OF MUSCLES Muscle roles Agonist (mobilizer) Antagonist Synergist Fixator Stabilizer Coordination and recruitment timing Coordination Efficient recruitment order, conserves energy Stabilizers should contract before mobilizers Timing: Order in which motor units and muscles contract Biarticular muscles: Act on two joints at once Allow simultaneous flexion/extension of lower limb joints. Can act on one or both joints Parallel shifts: Flex one joint, extend other joint Countercurrent movements: Flex both joints Active insufficiency Maximally shortened, flexing both joints Cannot contract any further, susceptible to spasm Passive insufficiency Maximally lengthened, extended at both joints Cannot stretch any further, susceptible to stretch injury SUGGESTED CLASSROOM AND STUDENT DEVELOPMENT ACTIVITIES PROVIDE AN OVERVIEW OF CLASS Before class, write a short, schematic overview of the class on the board, then go over it at the beginning of class. For example: Today's class covers: Structural features of skeletal muscles Contractile structures Continuity of muscle and fascia Muscle tension and contractile forces Changing roles of muscles Activities: Review, lecture, muscle skills lab, recap, and homework EXPLORING TECHNIQUE EXERCISE Viscoelasticity and plasticity in myofascia (p. 85) The main objective of this exercise is to improve quality of touch and to help students relate tissue properties to quality of touch. EXPERIENTIAL EXERCISES TO USE DURING LECTURE Provide short, experiential exercises that students can do from their seats during the lecture. This will help break up the lecture, help students between theory and application, increase the bodymind connection, and improve retention. Muscle shape identification and introductory palpation exercise Have students self-palpate or palpate on partner from a seated position five muscles of each different shape. Fusiform biceps Multipennate infraspinatus Flat obliques Triangular pectoralis or trapezius Rhomboidal rhomboids Identifying muscle roles Pick a certain movement, then have students analyze what muscles are acting in what roles: agonist, antagonist, synergists, neutralizers, stabilizers, etc. Feeling different types of contractions Have students explore contracting the same muscle group with isometric, concentric, and eccentric contractions. For example, have students stand and place their hand on the buttocks to monitor the gluteals. First have them isometrically contract the gluteals in place, then slowly bend at the hips to feel eccentric contractions, and return to standing to feel eccentric contractions. Feeling different speeds of isometric contraction Postural muscles work isometrically. To train them, people need to learn how to contract them slowly using one-third maximum effort. To help your students sense the difference between training slow and fast fibers in a muscle, have students explore isometrically contracting the deep, lower abdominals (which have many slow fibers for postural support) with a slow, light contraction. Contrast this by having them contract with a quick, fast contraction. Which is easier to hold? Have your students do the same type of isometric contraction in place with the biceps. The biceps are difficult to contract slowly and isometrically because they have primarily fast fibers. Muscle awareness exercise Guide your students though a progressive muscle relaxation exercise to improve muscular awareness, control, and relaxation. To do this, have them lie in a comfortable position, then systematically contract and relax the muscles, one at a time. This is an excellent exercise at night before going to sleep to help them relax, which is valuable for massage therapists because the more they can relax, the better able they will be to help their clients relax. © 2013 by Education, Inc. Foster, Instructor Resources for Therapeutic Kinesiology