Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
42 Cards in this Set
- Front
- Back
|
Biomechanics |
The application of mechanical laws to living structures, specifically to the locomotor system of the human body |
|
|
What are the uses of biomechanical analyses? |
- Improvement of sports skill techniques - Design of sports equipment - Prevention of injuries - Clinical analysis of movement pathologies - Design of protheses - Design of rehabilitation devices |
|
|
Qualitative analysis |
A non-numerical description of a movement based on direct observation. Conducted by teachers and coaches |
|
|
Quantitative analysis |
A movement is analyzed numerically based on measurements from data collected during the performance of the movement. |
|
|
Lever |
A rigid bar that turns about an axis. In the body, the bones represent the bars and the joints are the axes. |
|
|
What does contraction of the muscles provide? |
The force to move the levers |
|
|
Force point |
The exact point where the effort is applied |
|
|
Resistance point |
The exact point on which the resistance acts |
|
|
Fulcrum |
The axis of motion |
|
|
Force arm |
Perpendicular distance from the fulcrum to the line of action of the force acting on the force point |
|
|
Resistance arm |
Perpendicular distance from the fulcrum to the line of action of the resistance acting on the resistance point |
|
|
First-class lever |
Has its fulcrum at some point between the force and resistance point |
|
|
Second-class lever |
Has its resistance point at some point between the force point and fulcrum |
|
|
Third-class lever |
Force point between resistance point and fulcrum |
|
|
Force lever |
When the force arm of a lever is longer than its resistance arm and the mechanical advantage favours application of force at the sacrifice of speed |
|
|
Speed lever |
When the resistance arm of a lever is longer than its force arm and the mechanical advantage favours speed and range of motion at the sacrifice of force |
|
|
Mass |
The quantity of matter contained in an object |
|
|
Force |
mass x acceleration |
|
|
Weight |
The amount of gravitational force exerted on a body |
|
|
Torque (rotational force) |
The product of force and the perpendicular distance from the force's line of action to the axis of rotation Units: Newton-meters Force x moment arm |
|
|
Moment arm |
The perpendicular distance between the force's line of action and the axis of rotation |
|
|
Mechanical advantage of a lever |
The ratio of force arm length to resistance arm length |
|
|
Volume |
The amount of space a body occupies |
|
|
Pressure |
Force distributed over a given area P = force / area |
|
|
Compression |
Pressing or squeezing force directly axially through a body |
|
|
Tension |
Pulling or stretching force directly axially through a body |
|
|
Shear |
Force directed parallel to a surface |
|
|
Mechanical stress |
F / A Similar to pressure |
|
|
How to lift a heavy object from the floor |
1. Get someone to help you 2. Stand facing the object with your feet flat on the floor, shoulder width, and pointing straight ahead. Ensure you have a stable base of support so you don't slip when you lift 3. Face the object in the direction you intend to move it. Avoid twisting and simultaneous generation of high twisting torques 4. Keep the object are close to your body to minimize the reaction torque on low back 5. Get a good grip so you don't lose control 6. Bend knees and hips and keep back straight as possible. Avoid fully flexed or bent spine 7. Lift the object using the knee and hip extensor muscles 8. Carry the object close to your center of gravity |
|
|
Center of gravity |
An imaginary point in the centre of the body where the weight if the body is balanced |
|
|
Why is it useful to determine the center of gravity? |
1. Used to describe the movement of the body through space 2. Important for stability 3. Important factor in calculation of amount of work done |
|
|
Reaction board method |
Used for a static position of the human body. Assume that the center of gravity is the fulcrum or balance point and then apply the Principle of Levers (F x FA = R x RA) |
|
|
Segmental method |
Used for locating the center of gravity of a body in motion |
|
|
How can stability increase? |
1. Increasing body mass 2. Increasing size of the base of support in the direction of the line of action of an external force 3. Vertically positioning the center of gravity as low as possible 4. Increasing friction between the body and surface contacted 5. Horizontally positioning the center of gravity near the edge of the base of support towards the oncoming external force |
|
|
Newton's First Law |
Law of Inertia A body will maintain a state of rest or constant velocity unless acted on by an external force that changes the state |
|
|
Second Law |
Law of Acceleration Force = mass x acceleration |
|
|
Third Law |
Law of Reaction When one body exerts a force on a second body, the second body exerts a reaction force that is equal in magnitude and opposite in direction on the first body |
|
|
Momentum |
A mechanical quantity that is important in situations involving collisions mass x velocity |
|
|
Formula for work (J) |
force x distance |
|
|
Formula for power |
work per unit of time = force x distance divided by change in time OR force x velocity |
|
|
Differences between walking and running |
1. In running, there is a period when both feet are off the ground 2. In running, there is no period when both feet are in contact with the ground at the same time 3. In running, the stance phase is a much smaller portion of the total gait cycle than in walking |
|
|
Formula for running speed |
stride length x stride rate |
