KIN 365 1st EditionExam # 3 Study GuideMechanical Components of MovementI. Systems and Frames of Referencea. System: i. Body or group of bodies or objects whose motion is to be examinedb. Frame of Referencei. Stationaryii. MovingII. Orientation in Spacea. Body composed of movable segments or links that move fluidly through planes of motion and around axis of rotationb. Movement in relationship with thei. Groundii. Special planes and axes1. Includes botha. Horizontal planes and axesb. Vertical planes and axesIII. Orientation in Space: Planes of Motiona. Planes of motioni. Sagittal1. Vertical plane2. Divides right and lefii. Frontal1. Vertical plane2. Front and backiii. Horizontal 1. Horizontal plane2. Top and bottomIV. Orientation in Space: Axis of rotationa. Axis of rotationi. All planes have an axis of rotationii. Any axis that passes through body’s center of gravity is considered a principle or cardinal plane1. Think of it as line that runs perpendicular to one of planes of bodyiii. Axis1. Mediolateral2. Anteroposterior3. Superoinferiorb. Body and segmental planes and axisi. Each axis of rotation corresponds to a plane of motion1. Mediolateral AOR  Sagittal plane2. Anteroposterior AOR  Frontal plane3. Superoinferior AOR  Horizontal planec. Mediolateral axisi. Runs across midline as if body cut in half at waistii. Perpendicular to sagittal planeiii. Rotating around mediolateral axis occurs in sagittal plane of motioniv. Ex1. Flexion/extension of knee, hip, elbow, wrist2. Plantar and dorsi flexion of ankled. Anteroposterior Axisi. Runs across midline as if cutting body in half through belly buttonii. Perpendicular to frontal planeiii. Rotation around Anteroposterior axis occurs in frontal plane of motioniv. Ex1. Abduction/adduction of hip, shoulder2. Lateral flexion of spine3. Eversion/inversion of foot at subtalar and transverse tarsal jointse. Superoinferior Axisi. Cuts body in half through forehead/nose dividing body into right and lef halvesii. Perpendicular to transverse planeiii. Rotating around superoinferior axis occurs in transverse plane of motioniv. Ex1. Internal/external rotation of shoulder2. Protraction/retraction3. Supination/pronation of hand4. Horizontal flexion/extension at hip, shoulderV. Types of Motiona. Two main types of motion occur through these planes and around the axesi. Linear – straight lineii. Rotary – around fixed axis of rotationb. Linear motioni. Two main types1. Rectilineara. Movement in straight lineb. Exi. Running 50 meters2. Curvilineara. Movement NOT in straight line NOR around a fixed axisb. Exi. Arch of a baseball afer hit by a batii. High jumpii. Linear displacement1. How to measure or quantify linear motion2. Exa. Ran 50 metersb. Hit baseball 550 feetc. Rotaryi. Movement of an object around a fixed or restricted axisii. Ex1. Bending knee while walkinga. Rotary movement around knee axisiii. Three components1. Torquea. Turning force responsible for rotationb. Produces rotary motion2. Angular displacementa. Measurement of rotary motionb. Calculated in degreesi. Even though some points of motion move farther or faster than others ALL angles are the same degree3. Radius of rotationa. Distance from axis of rotation to the objecti. Greater the radius of rotation of a point, the longer the curvilinear or circular path it forms around axisVI. Forcea. Causes or tends to cause some kind of change in the motion or shape of an object or bodyb. Can be measured in i. Pounds (lb) = feet per poundii. Newtons (N) = meters per Newtonc. Product of mass and accelerationi. Mass = amount of matter in bodyii. Acceleration = speed at which the object is moving d. Pressurei. Force acting over a given areaii. Force / areaiii. Can be measured in1. Lbs/in^2 = pounds per square inch2. N/m^2 = Newtons per square meteriv. Ex1. Snow shoes2. By increasing area and distributing same weight over larger area = decreased pressuree. Mass gravity and weighti. Mass1. Amount of stuff, matter, object2. Key is amountii. Weight1. Mass in relation to gravity2. Effect gravity has on massiii. Farther away from center/axis = less weightiv. Center of gravity1. Point at which all of the mass of an object/body is evenly distributed (ie no net torque)2. Point in space, not a real object3. Can be outside of an object/bodya. Boomerang, diver in folded positionf. Inertiai. Property of a body or object that resists change in motionii. Ex1. When an elevator goes up quickly and then stops, you briefly keep movingiii. Directionally proportional to mass1. More mass an object has, the more inertia the object hasVII. Force and Movementa. Forcei. Something that possesses the capability to cause a change in motion of a system1. Pull of a push on an object in an attempt to affect the object’s motion orshapeii. Result of interactions (action/reaction)1. If no net force, no change in motioniii. Measured in Newton’s1. 1 Newton = force required to give a 1 kg mass an acceleration of 1 m/s/siv. Two main types1. Internal intrinsic forcesa. Forces acting within defined system2. External/extrinsic forcesa. Forces that interact with the system from the outside3. Only external forces can cause a change in motion of a body or objecta. Newton’s first law of motion – law of inertiai. If forces action on an object/system are balanced, the acceleration of that object will be zeroii. An object will only accelerate/change its direction if there is a net or unbalanced force acting on itiii. A system at rest will stay at rest, and a system in motion will stay in motion, in a straight line, until acted upon by an external force4. Internal forces only cause change in shape of the systemv. Muscles can be both the internal force that doesn’t cause change in motion and the external force that does cause a change in motion1. Only when muscle is the external force does it cause the change in motiona. Walkingi. Internal force – muscle pushing against groundii. External force – ground reaction fore pushing back up against usiii. It is the external force (the ground reaction force) that actually causes movementb. Properties of Forcei. Magnitude1. Because force is vector quantity, has magnitude2. Amount or size of the force appliedii. Direction1. Because force is vector quantity, has direction2. Way in which the force is applieda. Upward, downward, forward, backwardiii. Point of application1. Point or location where force is appliediv. Line of action1. Path along which vector travelsVIII. Force