(written from a Production point of view)
Xuyen Valdivia (also known as Sammy Valdivia) is a stuntman and stunt actor who served as stunt double for Garrett Wang on several episodes of Star Trek: Voyager. He received no credit for his work and a costume worn by him was sold off on the It's A Wrap! sale and auction on eBay where his name was misspelled as Sammy Valdavia.  More recently Valdivia performed stunts for J.J. Abrams' new Star Trek. 
In 2002, Valdivia was part of the stunt team which received a Taurus World Stunt Award for best fight in the sequel Rush Hour 2. He is a skilled martial artist and studied stunt driving in Rick Seaman's Stunt Driving School.
Valdivia has doubled for actors such as Dustin Nguyen (in V.I.P.), Reggie Lee (in The Fast and the Furious 2001), and Jason Scott Lee (in Balls of Fury 2007). Other film work includes the sequel Lethal Weapon 4 (1998), David Lynch's Mullholland Dr. (2001), Blade 2 (2002), The Scorpion King (2002, starring The Rock, and with Branscombe Richmond), Spider-Man (2002, starring Kirsten Dunst), Spider-Man 2 (2004, with Daniel Dae Kim and Donna Murphy), Constantine (2005), Steven Spielberg's War of the Worlds (2005), Clint Eastwood's Letters from Iwo Jima (2006), the two sequels Pirates of the Caribbean: Dead Man's Chest (2006) and Pirates of the Caribbean: At World's End (2007, both with Tom Morga and Theo Kypri), and Sylvester Stallone's action film Rambo (2008).
He performed also in television series including Nash Bridges, Charmed, Buffy the Vampire Slayer, Medium, and Heroes, where he doubled James Kyson Lee under stunt coordinator Ian Quinn. Among his recent projects are Peter Berg's Hancock, Ben Stiller's comedy Tropic Thunder, and the horror film Twilight. Star Trek is the third time he worked with director J.J. Abrams. He previously worked on the television series Alias and the sequel Mission: Impossible III (2006).