Muscles - Kinesiology

• Muscle body mass


  • Men: about 40%
  • Women: 30-35%
• Shivering


  A result of muscle contractions designed to produce heat
• Muscles can only pull, they can't push
• At birth you have all the muscle cells you will ever have
• Most mammals can walk run within a few hours of birth
• Muscular System


  • Over 650 muscles in your body
  • Each is shaped and sized according to its position in the body & its function
  • Provides support for the skeleton
  • Production of heat (Thermoregulation)
• Musculoskeletal System


  Supports, allows movement, Protects vital organs
• Components of the Musculoskeletal System

  • Body's bones
  • Skeletal muscles
  • Connective tissue that binds them together
• Skeletal muscle fibre


  Connects to bones directly through tough tissue fibres called tendons
• Bones


  • Bound tightly together with other bones through ligaments
  • Cartilage tissue at the ends of bones prevents the bones from grinding against one another
• Muscle pairs


  One contracts (shortens), the other relaxes (lengthens)
• Muscle tissues


  Work to contract & relax, results in movement
• Tendons


  Connective tissue bands that join muscles to bones
• Types of muscles


  • Smooth muscle
  • Cardiac muscle
  • Skeletal muscle
• Smooth muscle


  • Surrounds body's internal organs including blood vessels, hair follicles and urinary, genital and digestive tracts
  • Serve to propel material along length of those cavities
  • Slow, Sustained, rhythmic contractions
  • Involuntary
• Cardiac muscle


  • Heart muscle
  • Contracts Involuntarily
  • Cardiac muscle cells make up the heart
  • Fatigue-resistant
  • Striated
• Skeletal muscle


  • Striated, long cylindrical
  • Striped in appearance
  • Attached to bone via tendons and cross a joint
  • Voluntary, rapid, short-term contraction of great strength
  • 30-40% of body weight
• Properties of Muscle Fibres

  • Irritability - respond to stimuli
  • Contractibility - Shorten in length
  • Elasticity - Stretch and return to its normal position
  • Extensibility - Extend in length
  • Conductivity - Transmit a nerve impulse
• How muscles attach to bone

  • Indirect attachment - Epimysium extends past muscle as a tendon to attach to the Periosteum of a bone
  • Direct attachment - Epimysium adheres to and fuses with the periosteum
• Origin


  Least moveable part or the part of the muscle that attaches closest to the midline (axial skeleton)
• Insertion


  Most movable part or the part of the muscle that attaches further from the midline
• Action/Function/Motion


  What muscles do when activated
• Types of Contractions


  • Concentric contractions - Shortening
  • Eccentric contractions - Lengthening
  • Isometric contractions - Static
• Types of Exercise


  • Isotonic exercise - Controlled
  • Isometric exercise - No motion
  • Isokinetic exercise - Uses machines to control speed
• Ways to group muscles

  • By Action - Flexor, Adductor, Extensor
  • By Direction of Muscle Fibres - Rectus, Transverse, Oblique
  • By Location - Tibialis Anterior
  • By Number of Origins - Biceps, Triceps, Quadriceps
  • By Shape and Size - Maximus, Minimus, Longus, Brevis, Major, Minor
• Sternocleidomastoid


  Originates from manubrium and clavicle and inserts on the mastoid process
• Muscle groupings


  • Shoulder girdle
  • Thigh
  • Flexors, extensors, adductors, rotators, tensors
• Major muscle groups (Anterior)

  • Quadriceps
  • Rotator Cuff
  • Abdominals
  • Pectoral muscles
• Major muscle groups (Posterior)

  • Erector spinae
  • Rhomboids
  • Gluteals
  • Hamstring
  • Calf muscles
• Muscles can produce movement only at the joint that they cross
• Muscles can only pull, they cannot push
• Agonist (Prime mover)


  Responsible for movement
• Antagonist


  Opposing the action
• Synergist


  Muscles surrounding the joint being moved
• Fixators


  Muscles that steady the joints closer to the body parts
• Skeletal muscle unit


  Individual muscle fiber (Muscle cell)
• Connective tissue covering


  • Epimysium - Surrounds entire muscle
  • Perimysium - Surrounds bundles of muscle fibres
  • Endomysium - Surrounds individual muscle fibres
• Sarcolemma


  Layer beneath endomysium, sheath of connective tissue that surrounds muscle fibres
• Sarcoplasmic reticulum


  Network of channels associated with each muscle fibre, transports substances involved in muscle activation and stores calcium
• Myofibrils


  Thread-like strands within muscle fibre, contractile elements of the cell