EXSC 750
Advanced Sport
Biomechanics
COMPLETED EXAM
2024
, 1. What is the difference between linear and angular kinematics? How are they related to each other?
- Linear kinematics is the study of the motion of points, segments, and objects without considering the
causes of motion. Angular kinematics is the study of the motion of rotating bodies without considering the
causes of rotation. They are related to each other by the fact that any point on a rotating body has both linear
and angular motion, and that linear and angular displacement, velocity, and acceleration can be calculated
from each other using trigonometric functions.
2. What are the three types of muscle contraction? How do they affect the force production and energy
expenditure of muscles?
- The three types of muscle contraction are concentric, eccentric, and isometric. Concentric contraction
occurs when a muscle shortens while producing force, such as lifting a weight. Eccentric contraction occurs
when a muscle lengthens while producing force, such as lowering a weight. Isometric contraction occurs
when a muscle produces force without changing its length, such as holding a weight in a fixed position.
They affect the force production and energy expenditure of muscles differently: concentric contraction
produces less force than eccentric contraction, but consumes more energy; eccentric contraction produces
more force than concentric contraction, but consumes less energy; isometric contraction produces
intermediate force and consumes intermediate energy.
3. What are the factors that influence the coefficient of restitution of a bouncing ball? How can they be
measured experimentally?
- The coefficient of restitution (COR) of a bouncing ball is a measure of how much kinetic energy is lost or
retained during a collision with a surface. It depends on the material properties of the ball and the surface,
such as their elasticity, stiffness, and damping. It also depends on the initial velocity and angle of impact of
the ball. The COR can be measured experimentally by dropping or projecting a ball onto a surface and
recording its initial and final velocities using high-speed cameras or motion sensors. The COR is then
calculated as the ratio of the final to initial velocity.
4. What are the advantages and disadvantages of using inverse dynamics to estimate joint torques and forces
in human movement?
- Inverse dynamics is a method that uses kinematic and kinetic data to calculate the net joint torques and
forces acting on a body segment during movement. The advantages of using inverse dynamics are that it can
provide detailed information about the internal loading of joints and muscles, and that it can be applied to
any type of movement using standard equipment such as force plates and motion capture systems. The
disadvantages of using inverse dynamics are that it requires accurate measurement of segmental masses,
inertias, and centers of mass, which can be difficult to obtain for individual subjects; that it assumes rigid
body segments and neglects the effects of muscle activation, co-contraction, and deformation; and that it
does not account for passive structures such as ligaments, tendons, and cartilage that may also contribute to
joint stability and loading.
Advanced Sport
Biomechanics
COMPLETED EXAM
2024
, 1. What is the difference between linear and angular kinematics? How are they related to each other?
- Linear kinematics is the study of the motion of points, segments, and objects without considering the
causes of motion. Angular kinematics is the study of the motion of rotating bodies without considering the
causes of rotation. They are related to each other by the fact that any point on a rotating body has both linear
and angular motion, and that linear and angular displacement, velocity, and acceleration can be calculated
from each other using trigonometric functions.
2. What are the three types of muscle contraction? How do they affect the force production and energy
expenditure of muscles?
- The three types of muscle contraction are concentric, eccentric, and isometric. Concentric contraction
occurs when a muscle shortens while producing force, such as lifting a weight. Eccentric contraction occurs
when a muscle lengthens while producing force, such as lowering a weight. Isometric contraction occurs
when a muscle produces force without changing its length, such as holding a weight in a fixed position.
They affect the force production and energy expenditure of muscles differently: concentric contraction
produces less force than eccentric contraction, but consumes more energy; eccentric contraction produces
more force than concentric contraction, but consumes less energy; isometric contraction produces
intermediate force and consumes intermediate energy.
3. What are the factors that influence the coefficient of restitution of a bouncing ball? How can they be
measured experimentally?
- The coefficient of restitution (COR) of a bouncing ball is a measure of how much kinetic energy is lost or
retained during a collision with a surface. It depends on the material properties of the ball and the surface,
such as their elasticity, stiffness, and damping. It also depends on the initial velocity and angle of impact of
the ball. The COR can be measured experimentally by dropping or projecting a ball onto a surface and
recording its initial and final velocities using high-speed cameras or motion sensors. The COR is then
calculated as the ratio of the final to initial velocity.
4. What are the advantages and disadvantages of using inverse dynamics to estimate joint torques and forces
in human movement?
- Inverse dynamics is a method that uses kinematic and kinetic data to calculate the net joint torques and
forces acting on a body segment during movement. The advantages of using inverse dynamics are that it can
provide detailed information about the internal loading of joints and muscles, and that it can be applied to
any type of movement using standard equipment such as force plates and motion capture systems. The
disadvantages of using inverse dynamics are that it requires accurate measurement of segmental masses,
inertias, and centers of mass, which can be difficult to obtain for individual subjects; that it assumes rigid
body segments and neglects the effects of muscle activation, co-contraction, and deformation; and that it
does not account for passive structures such as ligaments, tendons, and cartilage that may also contribute to
joint stability and loading.
