Study Guides (238,202)
Canada (115,009)
Kinesiology (540)

Biomechanics Final Review.doc

6 Pages
Unlock Document

Western University
Kinesiology 2241A/B
Bob Vigars

Biomechanics Final Review Pattern: run jump ect, movement pattern Skill: pattern adapted to a task Technique: variations of a skill ex. Jump serve Style: unique timing or specialized moves Constraints: anything limiting can be human or event Closed skill: predictable environment for example a free throw, you are using biomechanical principles Open skill: unpredictable, execution less ideal Continuous: can be broken down into discrete but as a whole doesn’t have a definite begging or end OPO: is the goal of a movement, for example getting as high up as you can Biomechanical principles: factors affecting muscle forces (length tension relationship between muscles) momentum, radius of body parts, kinetic link being used, lift and drag forces, angle of projection/attack/attitude, rebound and spin of an object, methods of initiating body rotation Analysis process: 1. divide into discrete parts 2. mechanical purpose of each part (each parts opo) 3. biomechanical factors (acceleration, radius ect.) 4. biomechanical principles to achieve BP 5. critical features necessary for movements of specific skill Force arm: needs to be not inline with c of g because then you will not create any torque on the body Factors influencing movement: magnitude of net torque has a big effect, the amount created will effect the inertial characteristics of the object in ways or its rotational inertia or friction factors or the pathway available Rotary motion: represented by a straight line which starts at the axis of rotation and then draw it right out to where it rotates therefore you are drawing it out to where it rotates therefore you are making the radius, both points have the same angle thus the same angular distance but since the second has a greater linear distance it has a greater linear velocity Angular velocity: how fast a rotating body segment changes its position, measured in radian or degrees/second, 1 radian = 57.3 degrees, either clockwise or counter clockwise Angular acceleration: rare in human motion, it is equal to angular velocity plus torque, a large change in angular acceleration causes a great change in angular velocity, where a small change causes a s small change in angular velocity over a long time, it equal change in angular velocity over change in time Average angular velocity: time it takes for a body/segment/object to complete a motion, useful in quantitative analysis of motion, it equals angular displacement/time, it is an average for the entire time of the motion Instantaneous angular velocity: the angular acceleration at a particular point in the ROM it is equal to radius times angular acceleration, it determines the instantaneous velocity of any point on a system, you take this off the tangent R of rotation: symmetrical systems distance from axis of rotation to a precise point on a rotating system R of gyration: asymmetrical therefore most objects, distance from axis of rotation to a point where all the mass is concentrated, it is I=mk(2) or I=mr(2), if mass is spread far from axis it has a larger radius of gyration Angular momentumL L=inertia times angular acceleration, cant change without external torque, I is the rotational inertia therefore the bodies resistance 2 change, changing the inertia will change the angular acceleration drastically Angular impulse: Tt it is the torque multiplied by time of torque applied, no external torques can be applied while airborne therefore takeoff is very important, determines amount of angular momentum created Conservation of angular momentum: L-Iw, L will stay the same while airborne therefore you can either change angular accerlation by changing the inertia (smaller position) or opposite, think of the diver Turntable demos: twists about longitudinal axis, spins about a-p axis as get smaller you move faster Throw pattern: object behind body, sequential for increased high end point velocity, curvilinear path, mostly wheel-axle, open kinetic link (sequential from larger to smaller) max distance or velocity, you create angular momentum during the initial seg of body rotation Push pattern: all segments behind object simultaneous to increase force, rectilinear path, mostly lever motions, closed kinetic link, everything moves together Constraints to throw/push continuum: mass of projectile, volume/size/shape/profile, target area, strength/power/skill of person Open kinetic chain: throw or kick, end segment free (e.g. hand) sequential movement Closed kinetic chainL jump/push end segment restrained, simultaneous Steps of throw: 1.proximal 2.distal lags behind 3. achieve either max distance for velocity Magnitude of radius: is influenced by mass of object Final velocity: final v of hand at the end will determine projective v, the radius is the perpendicular distance from axis of rotation and release point, the kinetic link will also effect as will the radius Kinetic link characteristics: more massive segments at proximal end least massive at distal end, initial motion caused by torque applied 2 base Sequential motions: 1.proximal/massive self giving L 2. external T decelerates into proximal segment 3. to conserve L next segment acceleration (has smaller k) no increase in momentum just maintain velocity 4. Each successive segment acierates therefore increase angular acceleration than previous segment due to both the radius getting smaller and trying to maintain velocity Airborne reaction rotation: if u initiate a rotation about an axis it will happen opposite direction at same axis (law of conservation) Lever motions: flexion/extension/protraction/retraction/abd/adduction. Force creating Wheel-axle: medial/lateral rotation, prontation/supintion, inversion.eversion, muscle torque rotates a bone which becomes an axle, wheel is adjacent segment position at an angle 2 the axle, creates velocity Mechanical purpose of PUSH: max force/max power (force x velocity) max accuracy Push pattern + force activates: max strength movements demands simultaneous segmental rotations, move in rectilinear path, minimize accerlation in movements 2 avoid injury Push pattern + power activities: need both force and velocity to move fast, need higher force in a short time Power in jumping movements: body into space via segmental rotations, need large force, at take off c of g has high vertical velocity and moderate horizontal velocity and opposite for opposite goal Jumping motions: massive segments at end of chain (open ends) small at closed end, force through c of g, shoulder flexion, trunk extension and extension of legs Accuracy with velocity: consistency in movements, straight line motion just before release then rectilinear for short distance, curvilinear than flat will increase distance Sequence of movements for over-arm: 1. step forward with contra-lateral leg 2. pelvis 3. trunk rotation 4. transfer L to arm by stopping/reducing L in shoulder 5. shoulder protection 6. shoulder medial rotation 7. elbow extension 8. wrist/hand flexion Motion analysis: 1. segments involved 2. movements involved 3. sequence of moments 4. muscles causing movements Smaller/ lighter projectiles: allows greater # of segments contribute to performance allows for larger radius and smaller segments can contribute more Different performance errors: segmental positioning, sequence of movements/ time lack of power/strength Segmental positioning: beginners position more distal segment in front of proximal Sequencing of movements: beginner may move segments in clocks rather than overlapping each with adjacent segment therefore making it simultaneous not sequential 4 opo in projection: max horizontal distance (smaller than 45 degrees angle) max vertical distance (over 45 degree) max accuracy and max accuracy with speed Projection less than 45 degrees: long throw or jump Drag: has profile (form) drag or skin friction/surface drag, always resistive but can be motive Profile/form drag: magnitude is proportional to area of leading edge of projectile, higher pressure on leading side and lower pressure on trailing, suction on trailing side, can be decreased by streamlining, indirect relation between magnitude of flow velocity and pressure created V horizontal: have air resistance and ground friction so you want to have a high velocity or high hit of release but still lower than for vertical, greater projection angle the lower the horizontal velocity Vertical target: darts/archery, farther away needs more Vvert Horizontal target: basketball gold Aerodynamic drag fore: motion of air flowing past projectile, equal to projectiles velocity but in opposite direction Skin/surface drag: air sticks to projectile therefore rougher sticks more, secondary factor influencing magnitude of drag V vertical: height of c of g at takeoff plays a big role, location of fingers at take off effects –greater distance from c of g to finger equals a higher jump, gravity is first resistive than motive one arm down and one up has greater distance and will cause faster rotation Headwind: Vdrage + Vheadwind, increase flow velocity acting on body, increase total flow velocity acting on body tailwind Vdrag – Vtailwind, decrease flow velocity acting on body, increase flow velocity acting on a body skin friction: most noticed at low velocity, rubb
More Less

Related notes for Kinesiology 2241A/B

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.