There are two forms of kickback.

Rotational Kickback

The rapid upward and backward motion of the saw that can occur when the moving saw chain near the upper portion of the tip of the guide bar contacts an object such as a log or branch.

(Source ANSI B175.1 2000)

Linear kickback (also called pinch kickback)

The rapid push back of the saw that can occur when the wood closes in and pinches the moving saw chain in the cut along the top of the guide bar. 

(Source ANSI B175.1 2000)

SAWS UNDER 3.8 CUBIC INCH (62CC)

Effects of the ANSI standard on saw chain:

When replacing chain on saws below 3.8 cubic inch (62cc), any E&S chain with the proper pitch and gauge which is designated as low-kickback can be used.

Effects of the ANSI standard on guide bars:

When replacing guide bars, a E&S branded guide bar with the same bar length, nose radius (same number of sprocket teeth) and pitch can be used to maintain the low-kickback performance. (Source ANSI B175.1 2000)

SAWS 3.8 CUBIC INCH (62CC) AND LARGER

Effects of the ANSI standard on saw chain:

When replacing chain on saws 3.8 cubic inch (62cc) and larger, the saws may, but are not required to, meet the low-kickback acceptance criteria. Users should use this class of saws with specialized training in dealing with kickback.

Chain that complies with ANSI B175.1-2000 are identified as low-kickback replacewnt saw chain and carry the UL Classification marking.

Underwriters Laboratories.Inc., classified low kickback replacement saw chain in accordance with American National Standard low kickback safety requirements for gasoline powered chain saws (ANSI B175.1-2000), paragraphs S.11.2.4 and Canadian Standards Association CSA Z62.3-04 Clause 4.1.3.2, Type C Low-kickback replacement saw chain.