Kinesiology Exam #2

accuracy

uses fewest segments through smallest ROM

extensor reflex

facilitates low leg contraction during the support phase of walking

hop

same foot is used for takeoff and landing

leap

takeoff from one foot and landing on the other

maximum force

uses maximum segments through largest ROM

overarm

rotation at the shoulder; uses fewer segments, works simultaneously

perturbation

sudden change in conditions that displaces body position away from equilibrium

sequential

the ordered, proximal to distal activation of body segments to generate maximum velocity and efficient force transfer (speed and impact)

sidearm

medial pelvic rotation on opposite hip with arm abducted

simultaneous

movement patterns, muscle activations or joint actions that occur at the same time or within a very close time frame to achieve a specific goal (power and accuracy)

stable equilibrium

a state in which a body tends to return to its original position after being disturbed

stretch reflex

helps change shoulder and hip direction during walking

underarm

forward sagittal plane movement (reach)

unstable equilibrium

a state of balance where a system, when slightly disturbed or nudged, moves further away from its original position rather than returning to it

3 things that change projectiles in sequential movements

1. number of segments

2. ROM

3. lever length

How do base of support and projectiles relate to one another?

A stable base of support is critical for maximizing the velocity, accuracy, and efficiency of a projectile launch

How do you orient the base of support when catching or throwing projectiles?

catching : have a stable stance with feet slightly wider than shoulder-width apart, knees bent, and weight balanced to allow quick movement

throwing: step toward the target with the lead foot, aligning hips and shoulders to the target, while using the back leg for power

Where is the most efficient way to carry objects? Why?

close to your center of gravity and shorten resistance arms because it decreases torque

Coefficient of restitution

the amount of deformity of an object & the desire to return back to normal shape

What are the differences between locomotion on land and in the water?

1. buoyancy vs gravity

2. water resistance < ground resistance

3. water resistance > air resistance

4. maintain horizontal position vs vertical position

What % of power comes from arms during swimming?

85%

What differentiates the walk from the run?

Walking has double support, running does not. Running also has a flight phase

What % of ball speed comes from your lower extremities in throwing?

50%

What is the intersection of 3 planes known as?

center of gravity

What joint is responsible for postural sway?

the ankle joint; it is controlled by ankle plantar/dorsiflexors

Lifting is a form of what? How can we lift safely?

• lifting is a form of basic pulling

• Lift safely by minimizing the resistance arm to reduce the effort needed; it is most efficient when your body is nearly vertical

Why is increasing time/distance to lose momentum and kinetic energy done? What we can do to “absorb” impact

To reduce the impact force felt by the body and minimize injury

ex: hip/knee flexion on landing, crash pads, spreading impact over larger area

List the gait changes among the elderly

The elderly have:

• shorter stride length

• more time in double support

• reduced propulsion (slower, but more stable

Factors that contribute to joint stability

1. ligaments, muscle tension, fascia

2. bony structure

3. atmospheric pressure

Factors critical to maintain balance

1. size/shape of BOS

2. relation of line of gravity to BOS

3. height of COG

4. body mass

5. friction

6. segmental alignment

7. visual field

8. psychological factors

Sequential movement patterns in upper extremities (4)

1. overarm: rotation at shoulder

2. underarm: forward sagittal plan movement

3. sidearm: medial pelvic rotation on opposite hip with arm abducted

4. kicking: modification of locomotion

4 phases of a throw/strike/kick

1. preparatory movement

2. establishment of base of support

3. initiation of force

4. follow-through

Momentary contact

momentary contact between body and object (striking and hitting)

ex: volleyball pass

Projection

force develops kinetic energy that is held in hands and released

ex: dart throw

Continuous application

continuous force created by arms or legs

ex: archery

purpose of an overhand baseball pitch

to generate high velocity

nature of motion of an overhand baseball pitch

• sequential

• movement of the pitch follows a set order of phases, each phase depends on the previous one

planes of motion of an overhand baseball pitch

all 3

frontal: the stride phase

transverse: trunk rotation

sagittal: throwing of the ball

basic phases of an overhand pitch

1. windup

2. stride

3. arm cocking

4. arm acceleration

5. arm deceleration

6. follow-through

joints and movements involved in an overhand baseball pitch

joints: knee, hip, ankle, shoulder, elbow, wrist

movements: knee flexion & extension, hip flexion & extension, trunk rotation, shoulder external rotation