Over the decades rock has evolved in such a variety of directions that it has split into derivative genres. Some of the music got heavy, dark, distorted and eventually ended up being characterized as metal. A different group of artists went uptempo, simple, and loud, and became punk. Punk drew on its cousin, metal, and grew into hardcore punk, which eventually dropped the foreplay and bore a love-child in the form of thrash metal.

Thrash metal has grown up a little, and shirking the hyphenated prefixes of neo- or post- has become groove metal. Avoiding an extreme in either direction, groove metal is often mid-tempo, though frequently punctuated by quicker sections. Riffs retain the heaviness and distortion of traditional metal, but add a steady syncopation that defines the “groove.”

The bass guitar is typically distorted and amplified, its entire range boosted heavily alongside the treble to create a mid-scooped feel, and the drums use a double-kick with a frequency that qualifies as characteristic. Rhythm is stressed not only in guitars and drums but in vocals as well, with the flow and texture ranking as high in importance as tone and strength.

Early members of the genre took their influences from thrash metal bands such as Megadeth, blues metal groups such Black Sabbath, and hardcore punk rockers such as Black Flag to create a unique mixing pot of sound that is worthy of its own distinct genre within the overarching style of metal.

Five Finger Death Punch: With a name that gives a nod in the direction of classic Kung Fu movies, one can't help but move to a beat that is steady and firm, with a feeling and flow characteristic of groove metal. For a good example check out White Knuckles from their 2007 album From the Way of the Fist.

Lamb of God: With six studio albums, three DVDs, and a Grammy nomination under their belt, Lamb of God have achieved great success in their 16 years as a band. They've also had ample time to refine their sound, the fruits of which can be heard on Fake Messiah from their most recent album, Wrath, released in 2009.

Cavalera Conspiracy: A relative newcomer, having only formed in 2007, Cavalera Conspiracy has already garnered much well-deserved hype. Their sole studio album, Inflikted, also marked the first time the Calavera brothers had recorded together in the dozen years since Sepultura's Roots album in 1996. The album featured eleven tracks, but also included In Conspiracy, one of two bonus tracks.