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Kinesiology 2241A/B
Bob Vigars

Biomechanics 1 09/09/13 Biomechanics- mechanics of structure and function Mechanics- either static or dynamic Statics- non-moving systems Dynamics- kinetics and kinematics Kinetics- Forces that cause movement - Buoyancy - Friction - Centripetal - Gravity - Elasticity - Pressure Kinematics- Describing motion (what happens to object when kinetics are applied) - Velocity- m/sec., degrees or rads/sec. (57.3%) - Acceleration- change v OR change direction - Displacement- in meters or degrees/radians Efficient Movement - Minimal energy expenditure - Needed for endurance and repetitive sports Effective Movement - Not concerned with efficiency - Most appropriate movements to achieve mechanical purpose (MP) aka Overall Performance Objective (OPO) - Most appropriate sequence of movements (e.g. large parts then small parts)  Read Chapter 1 pages 1-6  Answer Questions # 1,3,5,6 on page 6  Read Module A pages 7-22  Answer Questions # 1,3,4,5,6 on page 22 Biomechanics 2 11/09/13 Axial Skeleton - Skull  pelvis o Skull- 29 bones o Thorax- 12 x 2 ribs and sternum o Vertabrae  Cervical- 7 bones  Thoracic- 12 bones  Lumbar- 5 bones  Coccyx- 4 bones - Each vertebrae is a bone with an articulation so easy to injure Appendicular skeleton - Pelvis  toes and shoulder  fingers o Upper extremities- shoulder to carpals  32 x 2 (right to left) o Lower Extremities- pelvis tarsals  31 x 2 (right to left) Note- alignment is key in biomechanics; it keeps everything moving properly. Shoes help with alignment Skeleton Functions - Protect vitals - Attachments for muscles - Levers and pulleys for muscle torques o Levers- Flexion and Extension- foul shot (shoulder flexion) o Pulleys- wheel axel systemmuscle pulls on bone (axis) and bone rotates  Tennis serve or football throw- overarm tosses  Kickers- planted foot is axel, other leg is wheel  If weight is too heavy, lever needs to be used Physical stress in Bones - Compression- Press together - Tension- pull apart - Torsion- twisting - Shear- tearing across Note- every time you hit ground with one foot while running, we hit it with double body weight. Occurs because all stress focused in one area; the more stress is spread, the lesser the overall effect Forces acting on player 1. Racket weight 2. Air resistance 3. Ball impact 4. Stroke type a. Flat stroke b. Top spin Stroke- ball drops so we can hit it harder and it will stay low i. Venus Williams injured herself by doing too much pronation Ligaments (bone to bone) - Harnessholds things together to guide motion Tendons (muscle to bone) - like ropes being pulledtransmit load Cartilage- Act like pads Properties of tendons and Ligaments - Elasticity- can deform and reform - Elastic limit- point of no return to original length, tendon can rip off of bone - Plasticity- tissue stretched beyond elastic limit (stays lengthened) - Evert foot to help with sprained ankles (point out outwards) Injuries to ligament/tendon - Take a long time to heal o Happens because limited vascularization in ligaments and tendons (not too much blood) Factors- stability of articulation - Bone arrangement- Strong = the ones that fir into other ones properly (knee, elbow joints) - Ligament Arrangement- quality and quantity - Muscle arrangement- Stabilizing lines of force - Laxity in a joint allows for mobility, lateral motions, a buffer zone to handle large stress ROM- range of motion - If bad then you can pop a hammie/ dislocate shoulder easily ROM Factors - Shape of articulation- elbow vs. shoulder - Tightness of muscles and ligaments - Size of adjacent tissue- muscle/adipose Biomechanics 3 13/09/13 Spatial frame of reference X - parallel to ground - Forward [+] and backwards [-] directions - Perpendicular to Y direction Y - Parallel to ground - Left [+] and right [-] directions - Perpendicular to x direction Z - Perpendicular to ground - Upward [+] and downward [-] directions Linear motion- motion in a line path - Rectilinear: straight line path (ex: drop ball, rowing boat) - Curvilinear: curved line path (discus flight, football throw w/ arc) Rotary Motion- rotates due to a fixed point - Fixed point- axis of rotation - Radius of Rotation- distance from any point to axis Planes and axes - Plane- a flat surface that divides body or segment (move in plane) - Axis- a pin or axle about which a body or segment rotates (rotate about an axis) - Movement occurs in a plane about an axis that is perpendicular to that plane - Motion of the human body described in 3 planes o Sagittal- left and right o Frontal- front and back o Transverse- top and bottom - Each plane has an associated axis Sagittal plane- Divides left and right - Perpendicular axis (sagittal is always M-L) o Mediolateral o Medio-lateral o M-L - Sagittal plane movements about M-L axis o Dorsiflexion- lift foot’s upper surface toward shin bone o Plantar flexion- depressing foot, pointing toes/foot away from shin (going on tippy toes) o Flexion- a bending, decreasing angle between adjacent bones o Extension- a straightening. Increasing angle between adjacent bones o Hyperextension- a bending joint beyond straight anatomical position (going past the neutral extension point) o Transverse Flexion- abduct shoulder/hip to parallel then move arm/leg medially (inward)- move arm across body, fingers pointing up? o Transverse Extension- from a position of transverse flexion, move arm/leg laterally (outward)  Transverse extend/flex only happens at hip/shoulder because they are multi- axial  If the front of the bone is leading, you’re still in the sagittal plane Frontal Plane - Perpendicular axis o Antero-posterior o A-P - Frontal Plane Movements about A-P axis o Abduction- limb away from mid-line of body o Adduction- moving limb toward mid-line of body o Depression- moving shoulder/jaw downward from an elevated position o Elevation- moving shoulder/jaw upward (shrug shoulders) o Lateral Flexion- bending trunk laterally away from mid-line o Radial Flexion- Moving hand laterally outward towards radius o Ulnar flexion- Moving hand medially toward ulnar bone o Transverse Abduction- flex shoulder/hip until arm/leg reaches parallel to ground then mo
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