Principles Of Kinesiology & Biomechanics

Question 1

Kinematics

Answer 1

Motion of a body without regard for the forces acting on the body

Question 2

Translation vs Rotation

Answer 2

Translation- linear motion of a body

Rotation- angular motion of a rigid body about some axis of rotation

Question 3

Osteokinematics

Answer 3

Motion of bones relative to 3 cardinal planes: sagittal, frontal, horizontal)

Question 4

Accessory motion

Answer 4

When joints move, the 2 parts should rotate and stay where they are in alignment- should NOT translate or move in space

Question 5

Closed kinematic chain

Answer 5

Anytime the hand or foot is fixed/ attached to something

Ex: squatting, pulling up/pushing up, standing up

Question 6

Open kinematic chain

Answer 6

Anytime the distal end of a limb is free

Ex: bringing hand to mouth, crossing leg, reaching up with arm

Question 7

Athrokinematics

Answer 7

Motion between articulate surfaces of joints during movement

Question 8

Joints stay centered/ opposed due to these 3 factors

Answer 8

1. Stabilizing function of muscle
2. Articular cartilage structure/ configuration
3. Tension in periarticular connective tissue

Question 9

Force

Answer 9

A push or pull that can produce, arrest, or modify movement, provides the impetus for movement AND stability of the body

Question 10

Internal force

Answer 10

Active or passive forces produced within the body

Active = muscle activation
Passive= tension in connective tissues

Question 11

External force

Answer 11

Gravity or another external load/physical contact from others

Question 12

How can we manipulate the effects of gravity?

Answer 12

By changing the length of the moment arm!

Think: w/ a bent elbow, weighted lateral arm raises feel a lot lighter than if your arm was straight- bending the elbow shortens the moment arm

Question 13

The ________ the center of gravity is, the __________ the base of support is, the __________ stable the object is

Answer 13

Closer (lower to the ground) ; larger ; more

Question 14

Torque

Answer 14

Force x moment arm

If moment arm length decreases- torque decreases
If moment arm length increases- torque increases

Question 15

Internal vs external torque

Answer 15

Internal= the product of the internal force (muscle) and the internal moment arm (of the muscle)

External= product of the external force (gravity/weights/etc/) and the external moment arm

Question 16

Muscle action at a joint

Answer 16

Potential of a muscle to create torque/ cause rotation in a particular direction and plane

Question 17

Lever (1st, 2nd, 3rd classes?)

Answer 17

A musculoskeletal lever is a rigid bar suspended across a pivot point

1st class- axis of rotation is between opposing forces (like a see saw)

2nd class- muscle has larger moment arm than external force (like a wheelbarrow)

3rd class- external force has more leverage than the muscle

Question 18

Mechanical advantage

Answer 18

A way to measure the efficiency of the lever.

Internal moment arm length / external moment arm length

Question 19

Describe the trade off between force and distance

Answer 19

Muscle plays the price (must produce tons of force) but gets the advantage of full rotation/ range of motion due to relatively small amount of shortening close to the joints axis

* the closer the moment arm is to the axis of rotation, the greater the rotation*

Question 20

Viscoelasticity

Answer 20

Tissues exhibit changes in the stress/strain curve as a function of time (rate and duration).

The faster the stretch, the greater the resistance
The slower the stretch, the less resistance

Question 21

Which is more important? Duration of force applied or intensity of force applied?

Answer 21

Duration of force applied!

Excessive force will have adverse effects and will delay the healing