Howcast - Learn how to do a jackknife from certified personal trainer James Rizzo in this home ab workout video from Howcast.

Howcast - Learn the eagle pose from certified yoga instructor Chelsey Korus in this Howcast video.

Howcast - Learn the dolphin dog from certified yoga instructor Chelsey Korus in this Howcast video.

Howcast - Learn the warrior two yoga pose from certified yoga instructor Chelsey Korus in this Howcast video.

Howcast - Learn how to do an arm-toning dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the whacking arms dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the stanky leg dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the tricep dip and kick dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the reggae dancehall step dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the hip-hop hooray arms dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the breakdancing push up dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the get under it dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the open and close it dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the kick 'n pick it up dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the in twist dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the shoulder roll over dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the two up two down dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the top rock dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the side snake lunge dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the pull down dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to do the arm swings dance move from fitness expert Rachel Warren in this hip-hop dance workout video from Howcast.

Howcast - Learn how to dance like Nsync to It's Gonna Be Me from Matt Lopez and DEF-C Crew in this hip-hop dance video, part two of a six-part Howcast series.

Howcast - Learn how to dance like Beyonce in Single Ladies from Matt Lopez and DEF-C Crew in this hip-hop dance video, the fifth in a six-part Howcast series.

Howcast - Learn how to dance like Beyonce to Single Ladies from Matt Lopez and DEF-C Crew in this hip-hop dance video, part four in a six-part Howcast series.