Howcast - Learn about shields in ninjutsu from Sensei Oliver Martin in this Howcast video.

Howcast - Learn how to switch from an ankle lock to a heel hook in this Howcast video about lower body submission techniques for jiu jitsu, judo, sambo and mma.

Howcast - Learn how to do a calf crush from inside guard leg lock in this Howcast video about lower body submission techniques for jiu jitsu, judo, and mma.

Howcast - Learn how to do a heel hook when mounted leg lock in this Howcast video about lower body submission techniques for jiu jitsu, judo, sambo, and mma.

Howcast - Learn how to do a heel hook leg lock in this Howcast video about lower body submission techniques for jiu jitsu, judo, sambo, and mma.

Howcast - Learn how to do a leg knot leg lock in this Howcast video about lower body submission techniques for jiu jitsu, judo, sambo, and mma.

Howcast - Learn how to do a toe hold MMA submission from Team Radical MMA head coach Rene Dreifuss in this Howcast video.

Howcast - Learn how to do a can opener MMA submission from Team Radical MMA head coach Rene Dreifuss in this Howcast video.

Howcast - Learn how to do a kneebar MMA submission from Team Radical MMA head coach Rene Dreifuss in this Howcast video.

Howcast - Learn how to do an arm triangle choke from the bottom half guard position from Team Radical MMA head coach Rene Dreifuss in this Howcast video.

Howcast - Learn how to do an arm bar from guard MMA submission using high guard from Team Radical MMA head coach Rene Dreifuss in this Howcast video.

Howcast - Learn how to do an inverted arm lock from guard MMA submission from Team Radical MMA head coach Rene Dreifuss in this Howcast video.

Howcast - Learn how to do a Jacaré-style kimura from guard MMA submission from Team Radical MMA head coach Rene Dreifuss in this Howcast video.

Howcast - Learn how to do a traditional kimura from guard MMA submission from Team Radical MMA head coach Rene Dreifuss in this Howcast video.

Howcast - Learn how to do a Cody McKenzie-style guillotine choke from Team Radical MMA head coach Rene Dreifuss in this Howcast video.

Howcast - Learn how to do a Marcelo Garcia-style guillotine choke from Team Radical MMA head coach Rene Dreifuss in this Howcast video.

Howcast - Learn how to do a wrist lock MMA submission from Team Radical MMA head coach Rene Dreifuss in this Howcast video.

Howcast - Learn how to do a rolling arm bar from guard MMA submission from Team Radical MMA head coach Rene Dreifuss in this Howcast video.

Howcast -Need a speedy sneak attack? Throw a sucker punch and catch your opponent off guard.

Howcast -After you've been in a destructive relationship, it can be hard to open up your heart and love again, but it is important to get over the pain and let your guard down.

Howcast - Learn the correct way to dribble a basketball from the Harlem Wizards in this Howcast basketball video.

Howcast - Learn how to do the rolling arm bar from Team Radical MMA head coach Rene Dreifuss in this Howcast MMA video.

Howcast - Learn how to do the arm bar from Team Radical MMA head coach Rene Dreifuss in this Howcast MMA video.

It's scary, but you can learn how to stand up to a bully — and come out on top.