Updated

The first full day of competition at the 2012 Olympics is Saturday and a total of 12 gold medals will be awarded, including one for the highly anticipated showdown between American swimmers Michael Phelps and Ryan Lochte.

Phelps has won a record 14 Olympic gold medals, including a record eight claimed at the 2008 Beijing Games, and he's after the all-time medal mark in London. Phelps has 16 Olympic medals and needs just three more of any kind here to break the current overall record of 18 set by Larisa Latynina, a Russian gymnast who competed in the 1950s and 60s.

For Phelps, who is expected to race in seven events here in London, his record quest begins Saturday with the most anticipated race of the Olympics, the 400- meter individual medley. Phelps, the two-time reigning Olympic champion in the event, was beaten by Lochte at U.S. trials last month.

In the women's competition, American Elizabeth Beisel figures to have a good chance to dethrone Australia's Stephanie Rice for gold in the 400m IM. Swimming medals will also be awarded for the men's 400m freestyle and the women's 400m freestyle relay.

History could be made in the first day of fencing, as Italy's Valentina Vezzali will try to become the first woman to win individual gold in the same event at four consecutive Olympics. Vezzali has taken the women's foil gold at the last three Summer Games and she can join Americans Carl Lewis (long jump) and Al Oerter (discus) as the only Olympians to pull off the feat.

The 38-year-old Vezzali's stiffest competition for foil gold is expected to be her compatriot Elisa Di Francisca.

A strong British team will line up in the men's road race to try to deliver super sprinter Mark Cavendish to the gold medal. Cavendish is the reigning world champion and has won 23 stages at the Tour de France, and his team includes Tour winner Bradley Wiggins.

The 250-kilometer race features nine ascents of Box Hill, and will likely be a struggle for control between attackers and teams wanting a sprint finish. Slovakian Peter Sagan is another favorite, while Australian Matt Goss and German Andre Greipel could challenge Cavendish in a sprint.

Gold will also be awarded in the men's team archery event and South Korea is the favorite after turning in a world record performance in Friday's ranking round. Im Dong-Hyun, who is legally blind in one eye, broke his own archery world record with a score of 699, eclipsing the previous 72-arrow record of 696 he set in May of this year.

The Koreans also broke their 216-arrow world record with 2,087 points as Kim Bubmin and Oh Jin-Hyek placed second and third -- Kim also broke Im's old individual mark.

South Korea, France, China, and the United States all finished in the top-four and will have a bye into the second round. The last country other than South Korea to win a gold medal in the men's team competition was the U.S. in 1996.

Shooting medals will be awarded in two disciplines on Saturday, with the women competing in the 10-meter air rifle and the men battling for gold in the 10- meter air pistol. Czech shooter Katerina Emmons, the wife of U.S. rifler Matthew Emmons, is out to defend her title against heavy favorite Yi Siling of China.

Tan Zongliang of China, who won silver in the 50m free pistol in Beijing, is the favorite in the men's air pistol.

The judo competition will begin by handing out medals in the men's 60-kilogram and women's 48-kg weight class. Rishod Sobirov is favored on the men's side and he could give Uzbekistan its first gold medal in judo. Romania's Alina Dumitru will attempt to defend her gold medal from the Beijing Games in the women's competition.

Weightlifting gold also will be on the line in the women's 48-kg category, and Wang Mingjuan of China is the leading contender in the event.

There will also be plenty of non-medal action on Saturday, including the first game for U.S. women's basketball and the start of the Olympic tennis tournament.

The American women have won the last four Olympic golds in basketball and will get their latest title defense started against Croatia. The heavily favored U.S. went 9-0 at the last major international competition -- the 2010 FIBA World Championships -- and had an average margin of victory of 35 points to win gold.

All told, there will be six preliminary round games in women's basketball on Day 1, including Australia, winner of the last three Olympic silver medals, taking on Great Britain.

Round 1 of the tennis tournament features top-seeded Roger Federer of Switzerland beginning his quest for his first Olympic gold in men's singles. Federer, who will face Colombia's Alejandro Falla in the opening round, won gold in doubles four years ago. On the women's side, fourth-seeded American Serena Williams will take on Serbia's Jelena Jankovic, while the top-ranked Bryan brothers of the U.S. will begin play in men's doubles.

Qualifying in men's gymnastics takes place Saturday, and the competitions will determine who advances to the team final, individual all-around final and apparatus finals.

Zou Kai and Chen Yibing return for China, which won team gold in Beijing four years ago. Japan, USA, Germany and Great Britain should do well in qualification and advance.

Yang Wei, the 2008 all-around gold medalist, is retired, leaving Japan's Kohei Uchimura as the favorite. Uchimura won silver in '08, as well as the last three world titles.

Zou returns as the defending gold medalist in floor exercise and horizontal bars, while Chen will try for another still rings title. Hungarian Krisztian Berki, the two-time defending pommel horse world champion, makes his Olympic debut. World vault champion Yang Hak-Seon will try to win South Korea's first Olympic gymnastics gold, while American Danell Leyva comes into the games as the defending world champ in parallel bars.

In women's soccer action, the U.S. will take on Colombia in one of six preliminary round games. The Americans rallied for a 4-2 win against France in their first game on Wednesday.

The American team of Misty May-Treanor and Kerri Walsh will begin their push for a third straight gold medal in women's beach volleyball as they take on the Australian team of Natalie Cook and Tamsin Hinchley in the preliminary round. Also, the U.S. men's team of Sean Rosenthal and Jake Gibb will take on South Africa's Freedom Chiya and Grant Goldschmidt.

In volleyball of the non-beach variety, women's preliminary round action begins with six matches on the docket. The U.S. women, who won silver four years ago in Beijing, will face South Korea.

A pair of American boxers will be in action on Saturday, as Terrell Gausha takes on Armenia's Andranik Hokobyan in the 75 kilogram weight class and Joseph Diaz Jr. squares off against Pavlo Ischenko of Ukraine. The U.S. collected only one medal -- a bronze -- at the boxing competition in Beijing.

All eyes will be on Great Britain's Zara Phillips as the equestrian eventing competition begins on Saturday with Day 1 of the dressage portion of the event. Phillips, who is the granddaughter of Queen Elizabeth II and daughter of Princess Anne, is one of five British riders in this event.

Eventing is sometimes referred to as the "three-day event" because it combines dressage, cross-country and a jumping finale. The individual and team competition run concurrently and medals are awarded for both.

Although no medals will be handed out, there will be a full slate of rowing action on Saturday with heats in nine separate disciplines. Most notably, the men's eights will feature medal favorites Germany, Great Britain, Canada and Netherlands.

There will also be early-round action in table tennis, badminton and team handball on Saturday.