The push (pinch kickback) and pull Freactions.
(SeeFig.2b)
A=Pull B= Solid objects C=Push
Kickback may occur when the nose or tip of the guide
bar touches an object, or when wood closes in and
pinches the saw chain in the cut. Tip contact in some
cases may cause a lightning-fast reverse reaction kicking
the guide bar up and back toward the operator. Pinching
the saw chain along the bottom of the guide bar may
pull the saw forward, away from the operator. Pinching
the saw chain along the top of the guide bar may push
the guide bar rapidly back toward the operator. Any of
these reactions may cause you to lose control of the
saw, which could result in serious personal injury.
Fig. 2b