Biomechanics of Sport Movements in a Sports
Physiotherapy Context (specialisation)
13 de setembro de 2025
Lesson 1 - Refresher
Translation Rotation
Pos - vel - acc Velocity while
rotating
Inertia:
Resistance of
the object to Ex: The mass Ex: We can
change motion of an object calculate Inertia is usually
state. Speed of will cause the inertia by thought of in
an object when change in mass x rotations and we
there are inertia. distance of have to consider
changes to the Heavier ball travels. At the the action of
state of will roll faster bottom of a gravity on the
motion. An than a lighter hill, we can bodies.
object will stay ball, altering know the
at rest unless a the resistance inertia of a
force is that inertia ball because it
applied, due to implies would keep
inertia. going at that
same speed
forever
Force Linear force Calculation of Torque is the
the moment tendency of a
arm (torque): force to cause the
Force x movement of an
distance object that has
one fixed point
, (about an axis) -
Force in rotation
The moment arm
is the
perpendicular line
to the center
The larger the
distance to the
center of the
object, the larger
the moment arm
(M), the bigger
the torque. A
bigger torque
means the force is
more easily
applied to
perform the
movement (ex:
pushing a two
way baloiço; more
effort for me to
resist with a
bigger torque)
Newton's 2nd Force = mass x Moment = Inertia
law acceleration -> x acceleration -> If
If you put i want to apply a
greater force to an object
acceleration in to rotate it, we
the throwing need to apply
of an object / rotational inertia
if you throw a Between a long
heavier object, stick and a ball
, the force of with the same
the object will mass, what is the
be greater easier to rotate?
Ex: if we drive The stick is harder
at a higher to rotate and has
speed and a bigger inertia
crash, the (more resistance
force in much to rotation - need
greater and to exert force).
more likely to Because the
cause damage particles of the
ball are closer
together, they
need a smaller
torque - lower
inertia
Momentum: The bigger the Rotational
Any object has mass or Momentum =
momentum velocity, the Inertia x
because it has more rotational velocity
mass, once it's momentum
moving. It will and the more
be preserved if effort is
it is not needed to stop
stopped. it
Impulse:
Change in
momentum
Segmental mass differs between men and women The human body
is porprotional to its own individual mass of the body.
, CM locations sometimes occur outside of the body and moments of
inertia can vary in their position.
Types of Force
Gravitational force: In theory the object and the earth attract each
other but the gravitational force appears to be vertical from us to the
earth because the earth has a much bigger mass - its inertia is much
higher. The higher an object is away from the ground, the less
gravitational force is applied.
Reaction force:
Physiotherapy Context (specialisation)
13 de setembro de 2025
Lesson 1 - Refresher
Translation Rotation
Pos - vel - acc Velocity while
rotating
Inertia:
Resistance of
the object to Ex: The mass Ex: We can
change motion of an object calculate Inertia is usually
state. Speed of will cause the inertia by thought of in
an object when change in mass x rotations and we
there are inertia. distance of have to consider
changes to the Heavier ball travels. At the the action of
state of will roll faster bottom of a gravity on the
motion. An than a lighter hill, we can bodies.
object will stay ball, altering know the
at rest unless a the resistance inertia of a
force is that inertia ball because it
applied, due to implies would keep
inertia. going at that
same speed
forever
Force Linear force Calculation of Torque is the
the moment tendency of a
arm (torque): force to cause the
Force x movement of an
distance object that has
one fixed point
, (about an axis) -
Force in rotation
The moment arm
is the
perpendicular line
to the center
The larger the
distance to the
center of the
object, the larger
the moment arm
(M), the bigger
the torque. A
bigger torque
means the force is
more easily
applied to
perform the
movement (ex:
pushing a two
way baloiço; more
effort for me to
resist with a
bigger torque)
Newton's 2nd Force = mass x Moment = Inertia
law acceleration -> x acceleration -> If
If you put i want to apply a
greater force to an object
acceleration in to rotate it, we
the throwing need to apply
of an object / rotational inertia
if you throw a Between a long
heavier object, stick and a ball
, the force of with the same
the object will mass, what is the
be greater easier to rotate?
Ex: if we drive The stick is harder
at a higher to rotate and has
speed and a bigger inertia
crash, the (more resistance
force in much to rotation - need
greater and to exert force).
more likely to Because the
cause damage particles of the
ball are closer
together, they
need a smaller
torque - lower
inertia
Momentum: The bigger the Rotational
Any object has mass or Momentum =
momentum velocity, the Inertia x
because it has more rotational velocity
mass, once it's momentum
moving. It will and the more
be preserved if effort is
it is not needed to stop
stopped. it
Impulse:
Change in
momentum
Segmental mass differs between men and women The human body
is porprotional to its own individual mass of the body.
, CM locations sometimes occur outside of the body and moments of
inertia can vary in their position.
Types of Force
Gravitational force: In theory the object and the earth attract each
other but the gravitational force appears to be vertical from us to the
earth because the earth has a much bigger mass - its inertia is much
higher. The higher an object is away from the ground, the less
gravitational force is applied.
Reaction force:
