Movement Abilities Across Lifespan

• Ability to move changes across the lifespan due to decreased muscle strength, nervous system changes, postural changes, injury, disease, and environmental factors.

Osteology and the Skeletal System

• Bones provide support as a framework, enable movement as mechanical levers, and offer protection.
• Bones also function in mineral storage and blood cell formation.
• Bone structure determines its function.
• Long bones have an epiphysis, periosteum (outer lining for cell reproduction), diaphysis (shaft), and a growth plate.
• Other bone types include sesamoid, irregular, short, and flat bones.

Terminology

• Tubercle, tuberosity, process, condyle, articular surface, epicondyle, fossa, facet, and foramen are terms used to describe bone features.

Carpal Bones

• The text mentions carpal bones, but doesn't list the specific ones

Spine

• The spine consists of 7 cervical, 12 thoracic, and 5 lumbar vertebrae, in addition to the sacral and coccygeal regions.

Bone Health

• Bone health is influenced by exercise, diet, aging, and hormones, including the effects of amenorrhea/oligomenorrhea, osteopenia, and osteoporosis.

Wolff’s Law

• Bones adapt to the stresses placed upon them, highlighting the importance of weight-bearing exercises.

Joints

• Joints are classified by motion or the type of tissue binding them.

Types of Joints

• Synarthroses/fibrous joints have no movement, examples being syndesmosis (tibia/fibula) and gomphosis (teeth).
• Amphiarthroses/cartilaginous joints allow limited movement.
• Diarthroses/synovial joints provide mobility.

Diarthrotic Joint Structures

• Diarthrotic joints contain a capsule, synovial fluid, cartilage (hyaline and fibrous), ligaments (passive support), and bursae.

Diarthrodial Joints

• Types of diarthrodial joints include hinge, ball and socket, irregular, condyloid/ellipsoidal, saddle, and pivot joints.

Joint Strength and Stability

• Joint strength and stability are influenced by the bones involved, ligament thickness and laxity, surrounding fat and muscle tissue, and the strength and flexibility of muscles crossing the joint, as well as structural resistance.

Classification of Joints - Movement in Planes

• Uniaxial joints move around one axis, allowing motion in one plane, with 1 degree of freedom (hinge, pivot).
• Biaxial joints move around two axes, allowing motion in two planes, with 2 degrees of freedom (condyloid, ellipsoidal, saddle).
• Triaxial joints move around three axes, allowing motion in three planes, with 3 degrees of freedom (ball and socket).

Kinetic Chain

• The body utilizes interrelated segments that influence one another.

Open Chain

• Open chain movement means the distal segment is open and free to move.
• Movement of one joint is independent of other joints in the chain.
• Single joint movement is typical in open chain exercises (arm curl, leg curl).

Closed Chain

• Closed chain movements occur when movement at one joint causes other joints in the chain to move.
• The distal segment of the body is fixed.
• Multiple joints are involved, typically moving against a linear resistance (push-up).

Arthrokinematics

• Arthrokinematics refers to minute movements in the joint surfaces, known as accessory movements or joint play.

Types of Arthrokinematic Movements

• Rolling/rocking is a rotatory motion.
• Sliding/gliding is a linear motion.
• Spinning is a rotary motion.
• Normal joint mechanics usually involves all three movements: rolling, sliding, and spinning.

Concave vs Convex

• Sliding direction depends on whether the moving surface is concave (hollow or rounded inward) or convex (curved or rounded outward).

Convex-Concave Principle

• When a convex surface moves on a concave surface, the convex joint surface slides opposite the bone's rolling motion.
• When a concave surface moves on a convex surface, the concave surface slides in the same direction as the bone's roll.

Concave on Convex

• Roll, slide and spin occur

The Convex–Concave

• ConveX slides in the Opposite direction
• Concave slides in the Same direction

Concave VS Convex Examples

• Tibiofemoral joint: Tibia is concave, femur is convex.
• Acetabulofemoral joint: Acetabulum is concave, femur is convex.
• Humeroulnar joint: Ulna is concave, humerus is convex.
• Glenohumeral joint: Humerus is convex, scapula is concave.

Closed Packed Position

• Maximum surface area contact occurs.
• Ligament attachments are farthest apart and under tension.
• The capsule is taut.
• The joint is compressed and difficult to distract.
• Typically occurs at extreme end of motion (full extension of elbow, wrist, knee, hip, dorsiflexion of ankle).
• Closed packed position offers mechanical stability, reducing the need for muscle action to maintain it.

Open Packed Position

• Ligaments and the capsule are slack.
• The joint can be distracted.
• Allows for accessory movements (arthrokinematics - roll, spin, glide).

Nervous System

• The nervous system consists of the central and peripheral nervous systems.

Sensory and Motor Areas

• The frontal cortex is responsible for motor functions including planning (prefrontal cortex), sequencing (premotor cortex), and executing actions (motor cortex)
• The parietal cortex is responsible for sensory functions.

Motor Neuron

• A nerve innervating a muscle is a motor neuron.
• Motor neurons carry impulses away (efferent) from the central nervous system.

Skeletal Muscle Functions

• Skeletal muscles protect joints and produce heat.

Skeletal Muscle Properties

• Contractability: ability to shorten and develop tension.
• Excitability (irritability): ability to respond to a stimulus.
• Extensibility: ability to move beyond resting length.
• Elasticity: ability to return to original length (passive tension).

Motor Unit

• Motor unit is a motor neuron plus all the muscle fibers it innervates.
• All or none principle: If one fiber in a motor unit contracts, they all contract.
• Fine motor control: Small motor units containing as few as 5 muscle fibers per nerve fiber (eye muscles, hand).
• Strength: Larger motor units with 1000-2000 fibers per nerve fiber.

Types of Skeletal Muscle

• Skeletal muscle is classified by speed of contraction and rate of fatigue.
• Type I: slow twitch, slow oxidative.
• Type IIa: intermediate (fast oxidative).
• Type IIb (Type II x): fast twitch, fast glycolytic.

Muscle Contraction (Strength)

• The number of motor units recruited (more = more force).
• Nervous system recruits from slow twitch to fast twitch.
• Henneman’s size principle: Smaller motor units are activated first, then larger ones.
• Frequency with which motor units are stimulated affects contraction strength.

Muscle Attachments

• Origin: stable end of a muscle.
• Insertion: moveable end of a muscle.
• Muscle shortens during contraction, moving the insertion toward the origin, crossing a joint.
• Actions depend on joint start position.

Types of Muscle Action

• Concentric: shortening.
• Eccentric: lengthening/resisting lengthening.
• Isometric: no movement.

SAID Principle

• Specific Adaptation to Imposed Demands

Properties of Muscle Actions

• Isometric: same length.
• Isotonic: same resistance, but tension generated by the muscle is not equal throughout the range of motion.
• Isokinetic: constant speed/velocity, measuring force production and torque.

Skeletal Muscle Variations

• More fibers = more force.
• Multi-pennate fiber arrangement produces greater force than uni-pennate.
• Most muscles in the body are multi-pennate.

Principles of Muscle Function

• Length-tension relationship: Ability to produce tension, influenced by sarcomere length for active tension and connective tissue length for passive tension.
• Force-velocity relationship: Force production depends on contraction velocity.
• Faster concentric contraction = less force.
• Eccentric action resists lengthening, greater force with increasing speed.
• Stretch-shortening cycle: Eccentric action immediately followed by a concentric action, enhances force production.

Gastrocnemius

• Origin: lateral condyle of the femur.
• Insertion: calcaneus (Achilles tendon).
• Action: plantar flexion, leg flexion.

Soleus

• Origin: fibular head.
• Insertion: calcaneus (Achilles tendon).
• Action: plantar flexion.

Hamstrings

• Origin: ischial tuberosity.
• Insertion: tibia, fibula.
• Action: flex at the knee, extend the hip, and rotation of the tibia and femur medially.

Muscle Roles

• Agonist: prime mover. Its contribution depends on muscle size, neural stimulation, fiber type, joint position, and fatigue.
• Synergist: assists prime mover.
• Antagonist: resists prime mover's action.
• Stabilizer/fixator: stabilizes joints proximal or distal to movement.
• Coactivation: simultaneous action of an agonist and antagonist.

Joints - Range of Motion

• Hypomobility: too little ROM.
• Hypermobility: too much ROM (subluxation = partially outside joint; dislocation = fully dislocated).
• Causes: injury, age, genetics.

Knee-Screw-Home Mechanism

• Tibiofemoral rotation (popliteus muscle).
• The knee is a modified hinge joint (bicondyloid joint) allowing flexion, extension, and tibiofemoral rotation at the end.

Notes on the Spine

• Herniated disk: nucleus pulposus pops out.
• Pain comes from the facet joints rubbing together.

Arthritis Types

• Osteoarthritis
• Rheumatoid arthritis
• Biochemical imbalance arthritis (gout)

Posture and Intervertebral Disk

• Cartilage: no nerve supply (aneural), no blood supply (avascular).

Joint Receptor Sensory

• Located in joint capsule and ligaments.
• Activated with motion, providing info about joint position and rate of motion.
• GTO (Golgi Tendon Organs): detects high force; inhibits agonist and activates antagonist.
• Muscle Spindle: activates agonist while inhibiting antagonist.

PNF Techniques

• Proprioceptive Neuromuscular Facilitation
• Reciprocal inhibition
• Contract agonist muscle while stretching antagonist muscle spindle
• Hold – Relax (autogenetic inhibition
• At the end ROM, contract isometrically, autogenic relaxation due to GTO and able to move to a new ROM

Proprioception

• Utilizes sensory input from muscle spindles, tendons, and joint receptors.
• Negatively affected by injury.
• Discriminates joint position and movement.
• Body uses vestibular and visual systems.

Active/Passive Insufficiency

• Applies only to multi-joint muscles
• Active Insufficiency: multi-joint muscle shortens over both joints simultaneously, creating slack and losing tension.
• Passive Insufficiency: multi-joint muscle is lengthened to its fullest extent at both joints, preventing full range of motion.

Muscle Injury

• Common at myotendinous junction.
• Causes: insufficient warm-up, fatigue, muscle imbalance, inflexibility, eccentric activity to decelerate high-velocity movements.
• DOMS (delayed onset muscle soreness): 48-72 hours; tears in connective tissue, sarcolemma, actin, and myosin fibers. More prevalent during eccentric action.

Determining Muscle Action

• Palpation: feeling the muscle through the skin.
• Drawing a line from origin to insertion along muscle fibers.
• sEMG (surface electromyography): measures conductivity when a muscle contracts.

Biomechanics

• Applies mechanical principles to the study of biological organisms.
• Helps to understand movement potential and limitations.
• Internal and external forces determine movement capabilities.

Mass vs Weight

• Body: any collection of matter.
• Mass: the amount of matter in a body.
• Weight: determined by the effect of gravity (W=mg).

Center of Gravity

• The point about which the body’s mass is equally distributed.
• Can be outside of the body.
• Lower when squatting, higher when arms are overhead.

Base of Support Affects Body Stability

• Increased stability: widen base of support, lower COG, large body mass (football lineman).
• Increased mobility: small base of support, high COG, COG near the base of support, small body mass, low friction.

Explore how movement abilities evolve throughout life. Understand the factors influencing these changes. Key areas include motor skills, skeletal system functions, and joint mechanics. Discover how bones adapt and the impact of kinetic chain exercises on movement.