Biomechanics Flashcards
Inertia
The reluctance to change
Newtons 1st law
Inertia
Newtons 2nd law
Acceleration
Newtons 3rd law
Action reaction
How is inertia measured
By looking at how much matter (mass or weight) a body has
Center of mass
The balance point of a body - body’s mass is equally distributed in all directions
Velocity
If a body is at a constant state of motion (stillness or movement) - stillness = 0 velocity
Acceleration
Any change in velocity (negative, positive or zero)
Force
Any “cause” (push or pull) that produces change in the state of rest or motion (football)
4 kinds of motion
No motion, linear motion, rotational (angular) motion, motion to stationary
No motion
Stability or static, centre of mass must be over base (touching toes)
Linear motion
Forces pass directly through centre of mass
Rotational (angular) motion
Forces pass “off Center” (swinging on a bar)
Motion to stationary
Attenuate energy (running into a wall)
Human motion caused by
Forces (torque) = muscle contractions
General motion
Rotational movement of limbs causes linear movement of body
Anatomical position
Standing, facing forward, arms at side, palms up, thumbs out
Frontal plane
Divides the body into front & back halves - cuts at ears - linear movement of body = side lunge or side stepping - rotational movement = moving arms and legs side ways (cartwheel)
Sagittarius planes
Divides body into side, down the midline - linear movement of body = walking, lunging forward & backward - rotational movement = moving head, arms, legs forward & backward (Flexion & extension) (summersault)
Transverse plane
Cuts body into top & bottom - rotational movement = rotation of head, trunk, limbs (turning on the spot)
Flexion
Reduces angle between joints
Extension
Increases angle between joints
