Exam #1 (ch. 1-4) Flashcards
-describes the MOTION of a body without regard to the forces or torques that may have produced the motion. Ex: walking velocity and angular displacement (ROM) of a joint.
Kinematics:
-describes the FORCES (or torques) that act on or within a body. Examples include compression of an article disc tension within a stretched ligament.
Kinetics:
Is it translation (rectilinear or curvilinear); rotation or both;
-walking
-ice skating
-cartwheel
-baseball throw
Walking: Curvilinear, joints: rotation
Ice skating: Rectinilear
Cartwheel: Curvilinear. joints: rotation
Baseball: Curvilinear of COG, rotation at multiple joints, the ball rotates and translates
Passive accessory motions at the ,metacarpophalangeal joint are greater ___________
in or near full extension
Which of the following is more stable: open-packed, close-packed
Closed-packed
What position is more closed-packed for the metacarpophalangeal joint?
near full flexion
At the index finger, the closed-packed position is associated with elongation and increased tension in the joint collateral ligaments. True or False?
True
What is the difference between force and torque?
-Force: a push or pull against a mass
-Torque: rotator equivalent of a force, its magnitude = to the product of a muscle force and moment arm.
Describe a particular aspect of a muscle’s contraction relative to a joint force using the term: force
Contraction force produced by the elbow flexor muscles can create significant compression with the elbow joint
Describe a particular aspect of a muscle’s contraction relative to a joint force using the term: torque
Torque produced by the elbow flexor can produce a rapid angular acceleration of the elbow, quickly bringing the hand to the mouth.
-a torque produced around a joint by an internal force such as muscle contraction.
Internal torque:
- a torque produced around a joint caused by an external force (such as gravity or manual resistance)
external torque:
-opposing internal and external torques about a joint (within a given plane) are equal, the joint is often in___________
static equilibrium:
Explain how changing the speed at which you lower a book to a table can affect the type of activation (e.g., eccentric and concentric) and choice of muscles.
-gravity is acting on the book and eccentric activation (“braking”) of the elbow flexors muscles. Elbow flexors control the movement by decelerating the descent of the book
-to accelerate the book at the rate that exceeds the pull of gravity, the elbow extensors must contract (concentric) to produce rapid descent of the book.
- Difference between force & pressure?
- How could these differences apply to protecting the skin of a patient with a spinal cord injury and reduced sensation?
- Give an example:
- -force is the magnitude of a push applied against the patient’s skin. Pressure is the force divided by the contact area.
-a force applied to a small surface area can create large and potentially damaging pressure (also called stress). - A person with a spinal cord injury often has impaired sensation and is not able to perceive a potentially damaging level of contact pressure. To reduce the pressure it is important to maximize the contact area between the skin and external object.
- A proper fitting wheelchair with a proper seat cushion maximizes the surface area that contacts the ischial region. reduce wrinkles in clothing
-describes the number of particles that exist in an object.
Mass:
-is a force that describes gravitational pull exerted on a mass
weight:
Describe the difference between mass and weight.
A person’s mass is known by dividing the person’s body weight (in newtons) by the acceleration caused by gravity 9.81 m/sec2)
-number of independent directions of movement allowed at a joint or the number of permitted
Planes of angular motion:
What are the 3 degrees of angular freedom for the shoulder, wrist, and elbow and their corresponding planes?
Shoulder = 3, Frontal, Sagittal, Transverse
Wrist = 2, Frontal, Sagittal
Elbow = 1, Sagittal
What is the axis of motion for the sagittal, frontal, and transverse planes?
Sagittal: M-L
Frontal: A-P
Transverse: Longitudinal
a device that can measure and report the specific gravity and angular rate of an object to which it is attached.
Inertial measurement unit: IMU
-provides a measure of angular rate
gyroscope:
-provide a measure specific force/acceleration
accelerometer:
An accelerometer and gyroscope consists of __________ unit.
Inertial measurement unit (IMU)
-experimental technique recording and analysis of myoelectric signals. Myoelectric signals are formed by physiological variations in the state of muscle fiber membranes
Electromyography (EMG):
