Biggest medal favorites in Rio

Bovada sets the odds of the Australian men's field hockey team winning gold at -125. Great Britain is second at +235.

Barnes is 5/4 to win the gold medal. He won the bronze in Beijing and Rio, according to Skybet.

Biles has won four gold medals in consecutive years at the World Championships, including the all-around. It would be a major upset if she didn't win in Rio.

Bolt is the favorite to win both the 100m and 200m again, according to Bovada. He's at -225 in the 100m and -500 in the 200m, followed by USA sprinter Justin Gatlin in both events.

The Brazilian soccer team is +110 to win the gold in Rio, according to Bovada. Argentina is second at +450, according to Skybet.

The hosts are the frontrunners to win men's volleyball at 2/1. Team USA isn't far behind at 7/2, according to Skybet.

The Brazilian women's volleyball team are overwhelming favorites to win the gold at 11/10 odds. USA is second at 3/1, according to Skybet.

Campbell won gold in the 4x100m freestyle in London, and also won two bronze medals in Beijing and won gold in the 2014 Pan Pacific Championships and 2014 Commonwealth Games.

Cheruiyot won the bronze medal in the 10000m and silver in the 5000m in London. She claimed gold in the 10000m at the 2015 World Championships.

Conlan won bronze in the flyweight class in London, and he's 6/4 to bring home the gold for Ireland in Rio, according to Skybet.

The top men's tennis player in the world, Djokovic is favored to win men's singles tennis for Serbia.

Eaton is the defending gold medalist in the decathlon, and he also claimed gold in the 2015 World Championships for Team USA.

Farah won both the 1000 meter and 5000 meter in London. He also won both events in the 2015 World Championships and 2013 World Championships.

Felix took home the gold in the 200m in London, while finishing second in Beijing and Athens. She's among the frontrunners going into Rio.

Jorgensen is the overwhelming favorite to bring home the gold for Team USA in the triathlon at -200, according to Bovada.

Koch won gold in the 200m breaststroke at the 2015 World Championships and the 2014 European Championships. He's favored to win in Rio for Germany.

After winning both events in the 2015 World Championships, Ledecky is expected to win easily in Rio.

Phelps is looking to add onto his 18 gold medals, and he remains the clear leader for the 100m butterfly and 200m individual medley.

Schwanitz finished 10th in shot put at the London Games, but she's become an elite shot putter since then. The German won gold at the 2016 European Championships and the 2015 World Championships.

Uchimura won the all-around for Japan in London, and has also won the all-around six times at the World Championships.

Team USA is nearly insurmountable 1/14 to win gold in Rio. Spain is second at 10/1, according to Skybet.

Team USA is 1/12 to win the gold. Australia is second at 13/2, according to Skybet.

This year's USA women's squad is arguably the best in history. They go into Rio with most prognosticators expecting an easy gold medal win.

Team USA is favored to win their third consecutive gold medal at +185. Germany comes in second at +295, according to Bovada.

Williams is the defending gold medalist in women's singles, and is coming off of a Wimbledon win. She enters Rio as the clear favorite.