4.3: fundaments of biomechanics
Biomechanics: studies the forces caused by and applied to the human body, and the effect they have on
its motion.
Can be divided into 2 areas, kinematics, and kinetics:
Kinematics
the study of motion (change in position) of a body/object
→ linear motion: straight line, same direction and speed (hockey puck pass)
→ curvilinear motion: curve (shot-put in air)
→ angular (rotational) motion: around an axis (gymnast around a high bar)
→ general motion: the combination of linear and angular (swimming, running, javelin…)
Deals with vectors and scalars
Vectors Scalars
They measure both magnitude (size) and direction Measures magnitude
-Represented by arrows (← / →) -Has no particular direction associated
-length of the vector is proportional to the -e.g. the time it takes to run 100m, the speed
magnitude of the variable posted on a road sign…
4.3: fundaments of biomechanics 1
, Kinetics
the forces involved in the movement of an object/body
→ linear kinetics: force, gravity, mass, and weight
→ angular kinetics: torque (movements), levers
Can be measured in Newtons (N)
Can be internal or external
Internal External
Forces generated by muscles pulling on bones Forces acting without gravity or any body contact
(tendons) across joint surfaces with the ground, environment, equipment…
force: a push or pull on an object
speed: the maximum rate at which a person is able to move their body
velocity: rate at which an object changes position
displacement: distance measured in a stated direction
acceleration: rate of change of velocity (speed/direction) per second
momentum: the amount of motion possessed by a moving object
impulse:force x time. The motion (momentum) of a body depends not only on the force, but also the
duration (time) the force is applied
Distance (d): how far an object travels
*Doesn’t depend upon direction
e.g; distance of the skier from A to B
Displacement (s): the difference between an
object’s position and it’s final position
*It does depend on direction
e.g. of directions: [+ and -], [N, S, E, W], angles…
4.3: fundaments of biomechanics 2
Biomechanics: studies the forces caused by and applied to the human body, and the effect they have on
its motion.
Can be divided into 2 areas, kinematics, and kinetics:
Kinematics
the study of motion (change in position) of a body/object
→ linear motion: straight line, same direction and speed (hockey puck pass)
→ curvilinear motion: curve (shot-put in air)
→ angular (rotational) motion: around an axis (gymnast around a high bar)
→ general motion: the combination of linear and angular (swimming, running, javelin…)
Deals with vectors and scalars
Vectors Scalars
They measure both magnitude (size) and direction Measures magnitude
-Represented by arrows (← / →) -Has no particular direction associated
-length of the vector is proportional to the -e.g. the time it takes to run 100m, the speed
magnitude of the variable posted on a road sign…
4.3: fundaments of biomechanics 1
, Kinetics
the forces involved in the movement of an object/body
→ linear kinetics: force, gravity, mass, and weight
→ angular kinetics: torque (movements), levers
Can be measured in Newtons (N)
Can be internal or external
Internal External
Forces generated by muscles pulling on bones Forces acting without gravity or any body contact
(tendons) across joint surfaces with the ground, environment, equipment…
force: a push or pull on an object
speed: the maximum rate at which a person is able to move their body
velocity: rate at which an object changes position
displacement: distance measured in a stated direction
acceleration: rate of change of velocity (speed/direction) per second
momentum: the amount of motion possessed by a moving object
impulse:force x time. The motion (momentum) of a body depends not only on the force, but also the
duration (time) the force is applied
Distance (d): how far an object travels
*Doesn’t depend upon direction
e.g; distance of the skier from A to B
Displacement (s): the difference between an
object’s position and it’s final position
*It does depend on direction
e.g. of directions: [+ and -], [N, S, E, W], angles…
4.3: fundaments of biomechanics 2
