Kinetics

The study of the actions of forces.  You might say that kinetics is concerned with what causes motion (or kinematics). Forces and the different types of forces (e.g., weight, friction, and muscle forces) are the cause of motion so they receive a lot of attention when describing the kinetics of motion. For example, if what you are observing is shoe traction, muscle forces required to produce movement, forces within joints, and impact strength of bone or sport equipment then you are observing kinetic concepts.

Biomechanical analyses and most biomechanical text books are organized according to kinematics and kinetics.  It is therefore a good idea to distinguish between a kinematic and kinetic question.  Test yourself by viewing the animation below and constructing kinetic and kinematic questions (my questions can be found by clicking this link).