Principles of Motion and Stability Flashcards
What is motion and stability?
Seen across variety of motor skills
Produces more force, velocity or accuracy
Developmental changes in movement occur according to biomechanic principles
What are developmental changes?
To develop a skill, must learn to use movement patterns that optimize performace
Growing/maturing = muscular and neural systems to generate more force
Changing body= changing individual constraints
What is Newton’s First Law?
Object at rest stays at rest
Object in motion stays in motion
Until acted upon by another force
What is inertia?
property of matter, it continues in its existing state of rest or uniform motion
What is momentum?
the product of mass and velocity
We must exert force to …
move an object
change the direction of something moving
What happens when there is more inertia?
More inertia = harder to move or stop
more force application is required
What is Newton’s Second Law?
Object’s force is related to mass and acceleration
F=ma
Objects acceleration is related to force applied and inversely related to mass
What is the relationship between force and distance over which force is applied?
Increase force delivered to objects moves an object further and faster
To further improve, increase linear distance over which force is applied
What is rotary or angular velocity?
When you throw, your arm rotates
Increase rotary range of motion can increase the rotary distance over which force is applied and max force and distance
Ex. windup in baseball
-Windup permits the person to project the object at greater velocity
What is Newton’s Third Law?
To every action there is an equal and opposite reaction
-When you push on something, it pushes back on you
- any force applied outside the plane of motion will lead to undesired reaction forces
Athletes exert as much force as possible in one plane
How would N3L be used?
Oppositional movements and directional force Characteristic of locomotor movements EX: Running -Lower body twists one way -Upper twists the other way -One leg forward -One arm opposite side forward
Why exert force in primary movement planes?
Use forces in the plane of motion to move yourself or and object
Avoid rotational movements that reduce force
How do you increase velocity of rotating limbs and projected objects?
Increase rotational velocity (swing faster)
Increase relative length (fully extend at release or contact)
Why wouldn’t you have your legs extended throughout?
Too much rotational inertia
Resistance to motion depends not only on mass but also limb length
-Increase length = increase resistance
-More energy required
What is an open kinetic chain?
Properly timed sequential movement of more body parts with ballistic effort
What are two elements of an open kinetic chain?
1) optimal sequence of movement
2) optimal timing of movements
What is the relationship of face and time?
To make an object move, increase force application fro a given time
To make an object stop increase time over which force is applied
To absorb force, people must increase the amount of time of impact or increase the area in which the force is absorbed
What is stability?
something that resists movement
What is balance?
Ability to maintain equilibrium
If you increase stability what happens to balance?
Balance is ensured however maintaining balance does not guarantee stability
Why wouldn’t some one want stability?
It inhibits mobility
How do you increase stability?
Increase base of support
Keep center of gravity low and inside base of support
What do locomotion skills require?
Momentary sacrifices of stability.
You must lose and regain balance
Strength, coordination and proprioception
