Exam 1 Study Guide PDF

Study guide **Exam 1 Study Guide** **Chapter 1: Anatomical Terminology and Planes of Motion** 1. **Anatomical Directions**: - Examples: Medial (toward the midline), Lateral (away from the midline), Superior (above), Inferior (below). 2. **Planes of Motion**: - **Sagittal...

Study guide **Exam 1 Study Guide** **Chapter 1: Anatomical Terminology and Planes of Motion** 1. **Anatomical Directions**: - Examples: Medial (toward the midline), Lateral (away from the midline), Superior (above), Inferior (below). 2. **Planes of Motion**: - **Sagittal Plane**: Divides body into left and right (e.g., forward lunges) (usually flexion and extension). - **Frontal Plane**: Divides body into front and back (e.g., jumping jacks) (usually abduction and adduction). - **Transverse Plane**: Divides body into top and bottom (e.g., torso rotations) ( usually twisting or rotating). 3. **Axes of Rotation**: - **Sagittal Plane** → Frontal Axis (e.g., flexion/extension). - **Frontal Plane** → Sagittal Axis (e.g., abduction/adduction). - **Transverse Plane** → Vertical Axis (e.g., rotational movements). **Chapter 2: Joints, Connective Tissue, and Muscle Mechanics** 1. **Joint Classifications**: - **Synarthrodial**: Immovable (e.g., skull sutures). - **Amphiarthrodial**: Slightly moveable (e.g., pubic symphysis). - **Diarthrodial (Synovial)**: Freely moveable (e.g., knee, shoulder). 2. **Tendons**: - Dense connective tissue attaching muscle to bone. - Function: Transmit force from muscles to bones to produce movement. 3. **Aponeuroses**: - Flattened tendinous sheets that connect muscle to bone or muscle to muscle. 4. **Connective Tissue**: - **Fascia**: Layer of connective tissue binding muscles together. 5. **Origin vs. Insertion**: - **Origin**: Proximal attachment, less movable. - **Insertion**: Distal attachment, more movable. 6. **Muscle Fiber Arrangements**: - **Parallel**: Longer fibers, greater shortening velocity (e.g., biceps). - **Pennate**: Fibers at an angle, greater force production (e.g., rectus femoris). 7. **Muscle Contractions**: - **Isometric**: No change in muscle length (stabilizes). - **Concentric**: Muscle shortens (causes motion). - **Eccentric**: Muscle lengthens under tension (controls motion). 8. **Roles of Muscles**: - **Agonist**: Prime mover. - **Antagonist**: Opposes the agonist to control or slow motion. **Chapter 3: Biomechanics, Levers, and Motion** 1. **Kinematics vs. Kinetics**: - **Kinematics**: Study of motion (position, velocity, acceleration). - **Kinetics**: Study of forces causing motion. 2. **Mechanical Advantages**: - Force amplification. - Speed/ROM amplification. 3. **Lever Components**: - **Fulcrum**: Pivot point. - **Force**: Effort applied. - **Resistance**: Load being moved. 4. **Lever Classes**: - **First Class**: Fulcrum between force and resistance (e.g., seesaw). - **Second Class**: Resistance between fulcrum and force (e.g., wheelbarrow). - **Third Class**: Force between fulcrum and resistance (e.g., biceps curl, most common in the body). 5. **Torque**: - **Definition**: Rotational force about an axis. - Causes **angular motion**, not linear. 6. **Lever System Advantages**: - **First Class**: Balance, speed, or force, depending on moment arms. - **Second Class**: Force amplification (e.g., lifting heavy loads with less effort). - **Third Class**: Speed and ROM amplification (e.g., human limbs). 7. **Angular vs. Linear Motion**: - Angular: Movement around an axis (e.g., spinning). - Linear: Straight-line motion. 8. **Object Diameter and Linear Motion**: - Larger diameter → greater linear motion from angular rotation. 9. **Newton's Laws of Motion**: - **1st Law**: Law of Inertia (object stays at rest or in motion unless acted on). - **2nd Law**: Law of Acceleration (F=maF = maF=ma). - **3rd Law**: Law of Reaction (equal and opposite forces). 10. **Momentum vs. Inertia**: - **Momentum**: Mass×VelocityMass \\times VelocityMass×Velocity (motion). - **Inertia**: Resistance to change in motion (property of mass). 11. **Impulse**: - Change in momentum due to applied force over time. 12. **Acceleration**: - Rate of change in velocity. - Directly proportional to force; inversely proportional to mass. 13. **Ground Reaction Force**: - Reaction force exerted by the ground in response to applied force. - **Hard surface** → Higher GRF. - **Sand** → Lower GRF. 14. **Types of Friction**: - **Static Friction**: Between stationary objects; highest resistance. - **Kinetic Friction**: Between moving objects; less than static friction. - **Rolling Friction**: Resistance of a rolling object; least resistance. - **Rank**: Static \> Kinetic \> Rolling. **Chapter 1: Introduction to Kinesiology** **Body Regions** - The body can be divided into **axial** and **appendicular** regions. - **Axial regions:** - Cephalic (head) - Cervical (neck) - Trunk (thorax, abdomen, pelvis) - **Appendicular regions:** - Upper limbs - Lower limbs **Planes of Motion** - Planes of motion divide the body into imaginary surfaces through which movements occur: - **Sagittal Plane:** - Divides body front to back. - Movements: Flexion/Extension (e.g., biceps curls, knee extensions). - **Frontal Plane:** - Divides body side to side. - Movements: Abduction/Adduction (e.g., jumping jacks, lateral flexion). - **Transverse Plane:** - Divides body top to bottom. - Movements: Rotation (e.g., spinal rotation, forearm pronation). - **Diagonal or Oblique Planes:** - Combine motions from more than one plane. **Axes of Rotation** - Movements occur around axes perpendicular to their respective planes: - **Frontal Axis:** - Side to side. (e.g., elbow flexion/extension) - **Sagittal Axis:** - Front to back. (e.g., hip abduction/adduction) - **Vertical Axis:** - Superior/inferior. (e.g., head rotation) **Skeletal System** - Composed of **206 bones**, divided into: - **Axial Skeleton:** - Skull, vertebral column, ribs, sternum. - **Appendicular Skeleton:** - Upper and lower extremities, shoulder, and pelvic girdles. - Functions: - Protection - Support - Movement - Mineral storage - Hemopoiesis (blood cell formation) **Types of Bones** - **Long Bones:** e.g., femur, tibia. - **Short Bones:** e.g., carpals, tarsals. - **Flat Bones:** e.g., sternum, scapula. - **Irregular Bones:** e.g., vertebrae, maxilla. - **Sesamoid Bones:** e.g., patella, bones in tendons like thumb and great toe. **Types of Diarthrodial Joints** - **Arthrodial (Gliding, Plane):** - Limited gliding movement. - Examples: Carpal bones of the wrist, tarsometatarsal joints of the foot. - **Condyloidal (Ellipsoid, Biaxial Ball-and-Socket):** - Movement in two planes without rotation. - Examples: Wrist, 2nd to 5th metacarpophalangeal joints. - **Enarthrodial (Multiaxial Ball-and-Socket):** - Movement in all planes. - Examples: Shoulder, hip joints. - **Ginglymus (Hinge):** - Wide range of movement in one plane. - Examples: Elbow, ankle, knee joints. - **Sellar (Saddle):** - Reciprocal reception at the thumb carpometacarpal joint; permits ball-and-socket movement except slight rotation. - **Trochoidal (Pivot, Screw):** - Rotational movement around a long axis. - Example: Radioulnar joint. **Goniometry and Movement Terminology** - **Goniometry:** - Measurement of range of motion using a goniometer to assess joint angles. **Terms Describing Movement:** - **Flexion:** Bending movement, decreasing angle. - **Extension:** Straightening movement, increasing angle. - **Circumduction:** Circular movement combining flexion, extension, abduction, and adduction. - **Rotation:** Movement around a longitudinal axis (Internal/External rotation). - **Other Terms:** - Abduction/Adduction - Eversion/Inversion - Plantar Flexion/Dorsal Flexion - Specific joint movements as appropriate. **Reference Positions** - **Anatomical Position:** Upright posture, facing forward, feet parallel, palms forward. - **Reference Lines:** Imaginary lines for anatomical and motion studies. **Anatomical Directional Terminology** - **Contralateral:** Opposite side. - **Ipsilateral:** Same side. - **Bilateral:** Both sides (e.g., right & left extremities). - **Deep:** Below the surface. - **Superficial:** Near the surface. - **Prone:** Lying face down. - **Supine:** Lying face up. - **Dorsal:** Relating to the back or top of the foot. - **Ventral:** Relating to the belly (anterior). - **Plantar:** Sole of the foot. - **Palmar:** Palm of the hand. **Joints and Movement** **Joint Classifications** 1. **Synarthrodial (Immovable):** - Examples: Sutures (skull), Gomphosis (teeth in sockets). - No movement; designed for stability. 2. **Amphiarthrodial (Slightly Movable):** - Examples: Pubic symphysis, intervertebral discs, rib-sternum joints. - Allow limited movement (e.g., pelvis twisting, ribcage expansion for breathing). 3. **Diarthrodial (Freely Movable):** - Known as synovial joints, surrounded by a capsule containing synovial fluid for lubrication. - Examples: Elbow, knee, hip, shoulder. - Stabilized by ligaments (e.g., ACL) and bursa sacs (prevent friction). **Key Joint Types** 1. **Hinge Joint:** - Examples: Elbow, knee. - Movement: Only one plane (flexion/extension). 2. **Ball and Socket Joint:** - Examples: Shoulder, hip. - Movement: Multiple planes (e.g., rotation, flexion, extension, abduction, adduction). **Notes on Muscle Structure and Function** **General Overview** - **Muscles:** Enable movement by pulling on bones at joints. - Movement depends on muscle fiber orientation and insertion points on bones. **Key Structures** 1. **Tendons:** - Connect muscles to bones. - Tough, flexible, fibrous connective tissue. - Shared tendons: Example - Quadriceps muscles share a common tendon for knee extension. - Tendon insertion affects joint movement direction (e.g., biceps vs. triceps). 2. **Aponeurosis:** - Tendinous expansions of dense connective tissue. 3. **Fascia:** - Fibrous connective tissue enveloping muscles, organs, and soft tissues. - Facilitates movement; restrictions can affect mobility. - Myofascial release techniques (e.g., foam rolling) can alleviate tension and restore mobility. **Origins and Insertions** - **Origin:** - Proximal, less movable attachment point. - Close to the midline of the body. - **Insertion:** - Distal, more movable attachment point. - Determines movement generated by muscle shortening. **Fiber Arrangements** 1. **Parallel Fiber Arrangement:** - Fibers run parallel to the long axis of the muscle. - Greatest shortening velocity and range of motion. - Subtypes: - Flat - Fusiform - Radiate - Circular/Sphincter 2. **Pennate Fiber Arrangement:** - Fibers oriented at an oblique angle to the long axis. - Greater force production due to increased cross-sectional area. - Subtypes: - Unipennate - Bipennate - Multipennate **Types of Contractions** 1. **Isometric Contraction:** - Muscle develops tension without changing length (no joint movement). - Example: Holding a weight without moving it (e.g., holding a bicep curl halfway). 2. **Isotonic Contractions:** - Muscle develops tension with joint movement. - **Concentric Contraction:** - Muscle shortens while under tension. - Example: Lifting a weight during a bicep curl. - **Eccentric Contraction:** - Muscle lengthens while under tension. - Example: Lowering a weight slowly during a bicep curl. **Roles in Movement** 1. **Agonist:** - Primary mover, responsible for creating movement. - Example: Biceps in a bicep curl. 2. **Antagonist:** - Opposite muscle group that relaxes to allow movement. - Example: Triceps during a bicep curl. 3. **Stabilizer:** - Muscle that stabilizes a joint, especially when another muscle crosses multiple joints. - Example: Hamstrings stabilizing the hip during knee movement. **Elbow Joint Planes of Motion - Notes** 1. **Primary Motion:** - **Sagittal Plane:** - **Flexion:** Bending the elbow (e.g., bringing the hand toward the shoulder). - **Extension:** Straightening the elbow (e.g., returning the arm to a straight position). 2. **Secondary Motion:** - **Transverse Plane (Radioulnar Joint):** - **Pronation:** Rotating the forearm to position the palm downward. - **Supination:** Rotating the forearm to position the palm upward. **Breakdown of Joint Components:** - **Humeroulnar Joint (Hinge):** Responsible for flexion and extension in the sagittal plane. - **Radioulnar Joint (Pivot):** Allows pronation and supination in the transverse plane. **Summary:** - **Sagittal Plane:** Flexion and Extension (primary motions). - **Transverse Plane:** Pronation and Supination (secondary motions via the radioulnar joint). **In class lecture** **Definitions:** 1. **Active Range of Motion (AROM):** - The individual moves voluntarily through the range of motion. - You do not manipulate or assist their movement. - Influenced by muscle strength, coordination, and willingness to move. - Provides information about the person\'s functional ability. 2. **Passive Range of Motion (PROM):** - The examiner moves the individual through the range of motion without their active effort. - Often results in higher ROM readings compared to AROM. - Limited by soft tissues (muscles, fascia, skin), joint articulations, or other restrictions (e.g., scar tissue, bone-on-bone contact). **Key Points:** - PROM typically gives **greater ROM** readings than AROM due to the lack of active muscle engagement. - Endpoints for PROM can be subjective and vary: - **Soft tissue stretch**: E.g., hamstring flexibility. - **Soft tissue opposition**: E.g., scar tissue or bulk stopping movement. - **Bone-on-bone contact**: E.g., elbow/knee extension where joint articulations stop motion. - **AROM and PROM provide different insights:** - AROM indicates **functional capacity** and **muscle control**. - PROM highlights **joint integrity** and **soft tissue flexibility**. - Challenges: - PROM requires manual assistance and can be labor-intensive. - Measurements can vary based on the subjective feel of the endpoint. **Using a Goniometer:** 1. **Parts of a Goniometer:** - **Axis:** Rotates at the joint. - **Moving arm:** Aligned with the moving body segment. - **Stationary arm:** Aligned with the stationary body segment. 2. **Reading the Goniometer:** - Goniometers have **multiple scales** (red and black numbers). - The **starting position** determines which scale to read: - **Elbow flexion:** Start fully extended; read the scale overlapping \"0\". - Ensure the moving arm aligns with the moving segment and the stationary arm aligns with the stationary segment. 3. **Common Mistakes:** - Misreading scales based on starting position. - Confusing range of motion with the angle between arms. - Always check which end overlaps \"0\" at the starting position to ensure correct readings. **Classroom Activity:** - Break into groups and use goniometers to measure AROM at various joints. - Focus on understanding: - Proper alignment of goniometer arms. - Reading the correct scale based on the starting position. - Differences in readings between joint types (e.g., elbow vs. hip flexion). **Example:** - Measure elbow flexion: - Fully extend the arm (starting at 0). - Flex the elbow. - Use the scale corresponding to the \"0\" overlap to record the range of motion (e.g., 0--150°). **Takeaway:**\ AROM and PROM measurements require precision and consistency to gather meaningful data. Understanding the mechanics of the goniometer and interpreting the correct scale is crucial for accurate assessments. **Notes on Joint and Muscle Structure from videos** **Overview of Joints** - Joints allow movement by connecting bones. - Movement range and freedom depend on bone configuration and articulation (bone interaction). - **Articulation/Arthrosis:** Connection between bones at a joint, allowing movement; facilitated by articular cartilage. **Joint Classifications** 1. **Synarthrodial Joints (Immovable):** - Examples: Sutures in the skull, tooth sockets (gomphosis). 2. **Amphiarthrodial Joints (Slightly Movable):** - Examples: - **Pubic symphysis:** Allows minor expansion and twisting. - **Intervertebral discs:** Enable limited spinal movement. - **Rib-sternum joints:** Allow ribcage expansion for breathing. 3. **Diarthrodial Joints (Freely Movable):** - Synonymous with **synovial joints.** - Key features: - **Joint capsule:** Contains synovial membrane and fluid. - **Bursa sacs:** Reduce friction, prevent joint pain, and swelling (e.g., bursitis). - Stabilized by ligaments (e.g., ACL in the knee). - Require healthy cartilage for smooth, pain-free motion. **Types of Diarthrodial Joints** 1. **Ball-and-Socket Joints:** - Examples: Shoulder (glenohumeral joint), hip. - Movement in multiple planes (e.g., swinging arm in all directions). 2. **Hinge Joints:** - Examples: Elbow, knee. - Movement limited to one plane (flexion and extension). - Provides stability and control; prevents excessive rotation. **Functional Design of Joints** - **Hinge Joint Stability:** Prevents excessive motion, ensuring efficient movement and structural stability (e.g., necessary for running or lateral movements). - **Ball-and-Socket Flexibility:** Enables wide ranges of motion critical for multidirectional tasks. **Summary:** Joints vary in structure and function based on their classification. Synarthrodial and amphiarthrodial joints have limited motion, while diarthrodial joints are highly movable. These differences ensure stability, range, and control across various bodily movements. **Notes on Muscle Structure and Function** **Muscle Function** - Muscles enable movement by shortening and pulling on bones at joints. - Shortening occurs along the **angle of pull**, determined by the orientation of muscle fibers. **Connective Tissues Involved in Movement** 1. **Tendons:** - Connect muscles to bones and are crucial for force transmission. - Tough, flexible, fibrous tissue. - Tendons can be shared by multiple muscles (e.g., quadriceps tendon). - **Insertion Point:** Determines the direction of movement caused by muscle contraction. - **Example:** Biceps insert anteriorly on the forearm to enable flexion, while triceps insert posteriorly for extension. 2. **Aponeurosis:** - Expansion of tendons; a broad, flat sheet of dense fibrous connective tissue. 3. **Fascia:** - A fibrous sheet that envelops, separates, and binds muscles, organs, and other soft tissues. - Plays a role in movement patterns and may cause friction or restrictions if remodeled improperly. - Techniques like **myofascial release** (foam rolling, massage) are used to restore tissue length and normalize movement. **Muscle Attachments** 1. **Origin:** - Proximal attachment (closer to the midline of the body). - The least movable part. 2. **Insertion:** - Distal attachment (farther from the midline). - The most movable part. - **Example (Biceps Brachii):** - Origin: Scapula (less movable). - Insertion: Radius (more movable). **Key Insights on Movement** - The relationship between origin, insertion, and tendon attachment dictates the type and direction of movement. - Knowing these relationships helps identify movement problems and design effective exercises. **Summary:**\ Muscles work with tendons, aponeurosis, and fascia to enable movement. Their origins, insertions, and fiber orientation dictate how they move bones at joints. Understanding these structures is crucial for analyzing movement and designing training or rehabilitation programs. **Notes on Muscle Fiber Arrangements and Contraction Types** **Muscle Fiber Arrangements** 1. **Parallel Fiber Arrangement:** - Fibers run parallel to the long axis of the muscle. - Allows for **greater shortening velocity** and **range of motion**. - Examples: Biceps (fusiform), flat, strap, radiate, and sphincter arrangements. 2. **Pennate Fiber Arrangement:** - Fibers align at an **oblique angle** to the muscle\'s long axis. - Advantages: **Greater force production** and more fibers per cross-sectional area. - Trade-off: Reduced range of motion and velocity. - Examples: Triceps (unipennate, bipennate, multipennate variations). **Muscle Contractions** 1. **Isometric Contraction:** - Tension develops without joint movement (e.g., holding a weight in a fixed position). - Good for stabilization and preventing motion. 2. **Isotonic Contraction:** - Tension develops with joint movement. - **Types:** - **Concentric:** Muscle shortens while generating tension (e.g., lifting a weight). - **Eccentric:** Muscle lengthens while controlling tension (e.g., lowering a weight). **Roles of Muscles in Movement** 1. **Agonist (Prime Mover):** - Main muscle causing movement (e.g., biceps during elbow flexion). 2. **Antagonist:** - Opposes the agonist\'s action (e.g., triceps during elbow flexion). - Relaxes to allow smooth movement or engages to control motion. 3. **Stabilizers:** - Fixate or stabilize a joint to allow movement in another segment. - Example: Hamstrings stabilize the hip during knee flexion. **Key Insights** - **Tension Development:** \"Contraction\" refers to generating tension, not necessarily shortening. Muscles can develop tension while shortening (concentric), lengthening (eccentric), or staying the same length (isometric). - **Practical Example:** - During a biceps curl: - **Concentric Phase:** Biceps shorten as the weight is lifted. - **Eccentric Phase:** Biceps lengthen as the weight is lowered. - **Stabilization:** Auxiliary muscles fixate other joints to isolate movement. **Summary:**\ Muscle fiber arrangement influences the force, velocity, and range of motion. Different contraction types serve specific roles in movement, while muscle groups (agonists, antagonists, and stabilizers) coordinate to produce and control motion. Chapter 3 **Biomechanics Notes** **Definition of Biomechanics** - Study of mechanics as it relates to the functional and anatomical analysis of biological systems, especially humans. - Applies physics, laws of motion, and forces to understand human movement. **Two Major Areas of Biomechanics** 1. **Kinematics**: Describes motion (movement details). - Time: How long it takes to move. - Displacement: How far you move. - Velocity: How fast you move. - Acceleration: How quickly movement changes. - Spatial factors: How motion occurs in space. 2. **Kinetics**: Studies forces causing motion. - Ground reaction forces (e.g., through force plates). **Biomechanics Labs and Motion Analysis** - **Motion Capture (Kinematics)**: - Infrared reflective markers track body segments in 3D space. - Captures displacement, velocity, and acceleration. - **Force Plates (Kinetics)**: - Measure ground reaction forces in vertical and horizontal planes. **Machines in Biomechanics** - Provide **mechanical advantage**: - **Force advantage**: Small input force moves a larger resistance (e.g., car jack, breaker bar). - **Displacement advantage**: Small input movement causes a larger movement (e.g., casting a fishing rod). - **Musculoskeletal System as Machines**: - Bones, joints, and muscles work as simple machines to balance forces and alter their direction. **Types of Machines in the Human Body** 1. **Levers**: Most common. 2. **Wheel and Axles**: Alter force direction and provide leverage. 3. **Pulleys**: Alter force direction, e.g., tendons acting over joints. *Note*: The body does not have inclined planes, screws, or wedges. **Levers in the Human Body** - **Components**: 1. **Force**: Input applied (e.g., muscle contraction). 2. **Axis (Fulcrum)**: Pivot point for rotation (e.g., joint). 3. **Resistance**: Load or weight moved by the force. - **Classes of Levers**: 4. **First-Class Lever**: - Axis is between force and resistance. - Example: Seesaw, neck extension. 5. **Second-Class Lever**: - Resistance is between axis and force. - Example: Wheelbarrow, standing on toes. 6. **Third-Class Lever**: - Force is between axis and resistance. - Example: Bicep curl, most body movements. **Action Steps for Study** - Draw and label diagrams for first-, second-, and third-class levers. - Familiarize yourself with examples of levers in the body. - Focus on the relationship between force, axis, and resistance for each class. **Levers** **Key Concepts** - A **lever** consists of a **force**, **axis (fulcrum)**, and **resistance** arranged in different orders, defining the class of lever. - **Mechanical advantage (MA)** = Length of force arm ÷ Length of resistance arm. - Determines how much force is required to balance or move a resistance. **Torque** - **Torque** = Force × Distance from the axis (moment arm). - Torque causes rotational movement around the axis. **Classes of Levers** 1. **First-Class Levers** - Axis is between force and resistance (e.g., seesaw, scissors). - Purposes: Balance, speed, or range of motion, depending on axis placement. - Example in the body: Head balanced on the neck (e.g., nodding). - Agonist and antagonist muscles stabilize the head. 2. **Second-Class Levers** - Resistance is between axis and force (e.g., wheelbarrow). - **Purpose**: Force advantage (move a large resistance with a smaller force). - Example in the body: Raising the body onto the toes. - Axis: Ball of the foot, Resistance: Body weight, Force: Calf muscles. - Rare in the human body. 3. **Third-Class Levers** - Force is between axis and resistance (e.g., rowing, shoveling). - **Purpose**: Speed and range of motion at the expense of force. - Example in the body: Bicep curl. - Axis: Elbow joint, Force: Biceps, Resistance: Weight in hand. - Most common lever type in the body. **Human Body Leverage System** - Built for **speed and range of motion**, not force. - Force arms in the body are typically short compared to resistance arms. - Muscles need significant strength to move long resistance arms (e.g., forearms). **Pulleys** **Key Concepts** - **Pulleys** redirect force and can increase mechanical advantage in multi-pulley systems. - **Mechanical Advantage** = Number of ropes supporting the load. - Single pulley: Changes direction of force, MA = 1. - Multiple pulleys: Increases MA (e.g., gym equipment with cables). **Pulley Example in the Body** - **Lateral malleolus** (ankle bone): Acts as a pulley for the **peroneus longus tendon**. - Function: Transmits force to the plantar aspect of the foot, allowing for eversion and plantarflexion. **1. Motion and Force** - Motion (movement) cannot occur without force. - **Types of Force:** - **Internal Force:** Muscle contractions (from the muscular system). - **External Force:** Interaction with external objects (e.g., being pushed, or objects colliding). **2. Types of Motion** - **Linear Motion:** Movement in a straight line. - **Angular Motion:** Rotational movement (e.g., a wheel turning). - Angular motion creates linear motion at the outer edges of the rotating object (e.g., a rock flung from a wheel). - **Relation Between Angular and Linear Motion:** - Angular motion at joints (e.g., hip/knee flexion and extension) generates linear motion (e.g., walking). - Larger radii (e.g., longer limbs or tools) produce greater linear velocity when angular motion occurs. **3. Examples of Angular and Linear Motion in Action** - Windmill blades: Longer blades produce higher linear velocity despite the same angular velocity. - Tools and equipment: - Long golf clubs = faster ball velocity. - Short golf clubs = slower ball velocity. - Vehicles: Larger wheels cover more ground per rotation than smaller wheels. **4. Newton\'s Laws of Motion** - Applicable to all linear and angular motion in biomechanics, sports, and physical activities. **Law 1: Law of Inertia** - **Definition:** - A body in motion stays in motion, and a body at rest stays at rest unless acted upon by an external force. - **Applications:** - Muscles generate force to overcome inertia (e.g., starting/stopping motion, accelerating, decelerating). - Examples: - Skier maintains trajectory until a force acts (e.g., wind resistance, friction). - Bowling ball rolls steadily on a slick floor unless force is applied. - **Mass and Inertia:** - Greater mass = greater inertia (more force required to change motion). - **Practical Examples:** - Sprinter overcoming resting inertia in starting blocks. - Slowing down a fast-moving object (e.g., stopping a ball). **Law 2: Momentum and Impulse** - **Momentum (p):** Quantity of motion = Mass × Velocity. - Greater momentum = Greater resistance to changes in motion. - Example: A larger, faster-moving object has more momentum than a smaller, slower one. - **Impulse:** - Impulse = Force × Time. - A force applied over time changes momentum. - **Applications of Impulse:** - Kicking a ball: The foot delivers an impulse, changing the ball\'s momentum. - Catching a ball: Extending arms slows down the ball gradually, reducing the force felt. - Helmets: Padding increases time of impact, reducing impulse on the skull. **Other Related Concepts:** - Reducing impulse to minimize impact: - Catching techniques (e.g., bringing arms inward when catching). - Protective equipment (e.g., helmet padding, Guardian caps for NFL players). **Summary of Key Biomechanics Applications** - **Angular Motion → Linear Motion Coupling:** - Seen in walking, running, tool usage, and equipment design. - **Newton's Laws of Motion:** - Inertia and momentum explain motion dynamics and resistance. - Impulse describes how forces modify motion. - **Practical Insights:** - Leverage force and radius for better efficiency in sports and physical tasks. - Use biomechanics principles to improve safety and reduce injury. **Newton's Second and Third Laws, Acceleration, Friction Notes** **Newton's Second Law: The Law of Acceleration** 1. **Definition of Acceleration**: - Acceleration is the change in velocity (not speed). - Positive or negative (e.g., braking = acceleration in the opposite direction of velocity). 2. **Key Concepts**: - **Equation**: Acceleration a=Fma = \\frac{F}{m}a=mF​ (Force divided by Mass). - Acceleration is: - **Directly proportional** to the force applied. - **Inversely proportional** to the mass of the object. - Larger mass requires more force to accelerate; smaller mass is easier to accelerate. 3. **Applications**: - Movement is rarely constant speed; it typically involves acceleration. - Example: A strong person pushing a heavy truck applies significant force, but the large mass limits acceleration. 4. **Muscular Force**: - High force is required to accelerate larger masses (e.g., big person reaching high speeds needs substantial effort). **Newton's Third Law: The Law of Reaction** 1. **Definition**: - For every action, there is an equal and opposite reaction. 2. **Applications**: - **Ground Reaction Force**: - Key to movement (walking, running, jumping). - The force exerted by the ground in response to the force applied by your feet. - Hard surfaces provide higher ground reaction force; soft surfaces (e.g., sand) provide less resistance. - Example: Walking on sand is harder because lower ground reaction force reduces propulsion. **Friction in Motion** 1. **Definition**: - Friction is the resistance between two surfaces in contact. 2. **Types of Friction**: - **Static Friction**: - Resistance between objects not yet moving. - Always **greater than kinetic friction**. - **Kinetic Friction**: - Resistance during motion between surfaces. 3. **Examples**: - **Static Friction**: - Pushing a sled: High initial force needed to start moving (overcoming static friction). - **Kinetic Friction**: - Once the sled moves, less force is required to keep it in motion. 4. **Factors Affecting Friction**: - **Surface Texture**: - Rougher surfaces = more friction. - Smoother surfaces (e.g., turf) = less friction. - **Normal Force**: - Increasing perpendicular force (e.g., coach standing on a sled) increases friction. - **Coefficient of Friction**: - Ratio describing the force required to overcome friction compared to the force holding surfaces together. 5. **Rolling Friction**: - Resistance of a rolling object (e.g., tires or balls) on a surface. - **Lower** than static or kinetic friction. **Summary Points:** - **Acceleration**: Change in velocity due to force; harder with higher mass. - **Reaction Forces**: Opposite and equal forces allow movement (e.g., ground reaction force). - **Friction**: - Static \> Kinetic. - Rolling friction is minimal compared to sliding friction. - Surface texture and applied force impact the frictional force.