BIOMECHANICAL PRINCIPLES
BIOMECHANICAL PRINCIPLES
What is Newton’s 1st Law?
Law of Inertia
-A body remains at rest or at a constant linear or angular velocity except when compelled by an external force to change its state.
What is inertia?
Amount of energy required to alter the velocity of a body.
What is inertia directly related to?
Directly proportional to mass.
Where is the center of mass typically located on the human body?
Just anterior to 2nd sacral vertebrae in upright.
What is meant by center of gravity?
Point where effects of gravity are completely balanced.
What is the mass moment of inertia?
What is the mass moment of inertia dependent on?
Mass, but also the distribution of that mass with respect to the axis of rotation.
Which is easier to move forward during the swing phase of gait of running, a leg that weighs 40 pounds that is flexed at the knee and hip or a leg that weight 40 pounds that is extended at the hip and knee?
Leg that is flexed at the knee and hip, due to the mass being closer to the axis of rotation.
What is Newtons 2nd Law?
Law of Acceleration
What is acceleration directly proportional with?
What is angular acceleration directly proportional with?
- torque
What is acceleration inversely proportional to?
What is angular acceleration inversely proportional to?
- mass moment of inertia
What is newtons 3rd Law?
-For every force, there is an equal and opposite directed force.
What does an electrogoniometer measure?
Measures angles of joints and their ROM.
What does an accelerometer measure?
Measure acceleration of either individual segment or whole body.
What is a force plate used for?
Measure the ground reaction forces generated by a body.
INTRO TO KINESIOLOGY
INTRO TO KINESIOLOGY
What is kinesiology?
Study of movement
What are the three cardinal planes of osteokinematics and the motions that occur in each of these planes?
Sagittal
Frontal (Coronal)
Horizontal (Transverse)
What is Degree of Freedon (DOF)?
Number of independent directions of movevment allowed at a joint.
What are the degrees of freedom of a uniaxial, biaxial, and triaxial joint?
Uniaxial= 1 DOF Biaxial= 2 DOF Triaxial= 3 DOF
What is the difference between a closed kinetic chain and an open kinetic chain?
CKC- Chain in which the distal segment is fixed and the proximal segment is free to move.
OKC- Chain in which the proximal segment is fixed and the distal segment is free to move.
Does osteokinematics or arthrokinematics describe the motion we visualize with movement?
Osteokinematics
Does osteokinematics or arthrokinematics describe the motion that occurs between the joint surfaces that you cannot visually see when observing?
Arthrokinematics