intro to kinesiology slides

Kinematics

General description of motion without regards to any forces at play.

Translation

Moving from one point to another point.

Rotation

Movement around a fixed axis of rotation.

Osteokinematics

Movement of the body or body segments within the three cardinal planes of movement.

Degrees of freedom

Freely available movement within the three cardinal planes of movement.

Transverse, sagittal, coronal

What are the three planes of movement?

Absolute

Where the segment is moving in space, plane of movement, etc.

Relative

Where one segment of a joint is moving relative to the other segment.

Open-chain

Any movement where the distal segment is freely movable.

Closed-chain

Any movement where the distal segment is fixed and the proximal segment is freely movable.

Osteokinematic

Goniomotors only measure motion.

Arthrokinematics

Movement of the joint surfaces relative to one another.

1. Range of motion

2. Stability

3. Movement pathway

4. Force distribution

What does joint shape influence?

Stability

When the tibia rolls anteriorly on the femur, it also slides posteriorly in order to maintain contact, dissipate forces across joint, and maintain joint ___.

Convex-on-concave

Roll and glide in opposite direction.

Concave-on-convex

Roll and glide in same direction.

Arthrokinematics

Loss of ROM may be due to deficits in ___.

Zero position

Anatomical position of a joint, where it is 0°.

Open-packed position

Position of joint where ligaments are on slack and there is more accessory motion (joint play); a.k.a. "resting position" when injured with swelling.

Close-packed position

Position of joint where there is maximal contact between the two joints surfaces (maximal joint congruency), where the ligaments are taut, and there is maximal joint congruency.

Synarthrosis

Joints connected by dense fibrous tissue that allow very little movement but absorb force.

Cartilaginous (amphiarthrosis)

Joints connected by fibrocartilage, allow some movement and rotation, and absorb force.

Diarthrosis (synovial)

Joints that have a capsule or ligament surrounding it, some amount of synovial lining that provides force distribution and protection, and are freely movable.

1. Synovial fluid

2. Articular cartilage

3. Joint capsule

4. Synovial membrane

5. Ligaments

6. Blood vessels

7. Sensory nerves

What elements are always associated with diarthrodial (synovial) joints?

1. Intra-articular discs or menisci

2. Peripheral labrum

3. Fat pads

4. Bursa

5. Synovial plicae

What elements are sometimes associated with diarthrodial (synovial) joints?

Position

Axis of rotation within joints is rarely ever fixed. Changing axes of motion by changing ___.

1. Magnitude

2. Direction

3. Point of application

What are the features of force?

Internal force

Forces produced within the body; can be active (muscle) or passive (ligaments, capsules, etc.).

External force

Forces outside the body (gravity, ground reaction force, etc.).

Net force

Movement is the result of a _ acting on a body.

Zero

No movement occurs when the net force is _.

Joint reaction force

Forces acting around a joint can also produce a force on that joint.

Rotary force

Muscle force normal, or , causes rotation of joint around axis.

Compression

Muscle force tangential causes or traction at joint.

Magnitude

Forces acting around a joint produce a .

Moment arm

Distance from axis of rotation.

External torque

External force x distance from axis of rotation (joint).

Internal torque

Internal force (muscle) x distance from axis of rotation (joint).

Small

Long moment arm allows the person to use a ___ force to produce torque.

Lever

Rigid body suspended over an axis of rotation.

First-class lever

Opposing forces are on opposite sides of axis of rotation.

Second-class lever

Both external force and internal force are on same side of axis of rotation, but internal force has longer moment arm.

Third-class lever

Both external force and internal force are on same side of axis of rotation, but external force has longer moment arm. This gives the internal force producer (muscle) a greater ROM.

Isometric contraction

Muscle is producing force with no change in length.

Concentric contraction

Muscle is producing force while shortening.

Eccentric contraction

Muscle is producing force while lengthening.

Agonist

Muscle that acts to cause a movement.

Antagonist

Muscle that opposes a movement.

Synergists

Muscle groups working together to produce the same motion.

EMG

Record of electrical changes within the muscle as an action potential propagates.

1. Timing of electrical activity

2. Magnitude of electrical activity

How is EMG quantified?

Force

EMG activity is not synonymous with the amount of , especially when activity occurs during movement.

Eccentric contraction

Higher force output with higher lengthening velocity during ___.

Motor units

EMG activity may increase while force production is decreasing because more are being recruited.