The United States extended their lead in the medal count on Thursday and they will look to widen the gap even further on Friday. Team USA won four track & field medals on Thursday and they will go for another strong day on the track on Friday.

Six track & field gold medals are up for grabs Friday and the United States figures to be in the middle of the action. They are among the favorites in the women's 4x100m relay and the men's 4x400m relay. They will also be medal contenders in the women's 1500m and men's pole vault.

In addition to the track and field events, American Connor Fields should contend for a medal in men's BMX.

Here is how the top five looks in the latest medal count:

1. United States, 90 (39 gold, 25 silver, 26 bronze)
2. China, 80 (37, 24, 19)
3. Russia, 56 (12, 21, 23)
4. Great Britain, 52 (25, 13, 14)
5. Germany, 37 (10, 16, 11)

For a complete breakdown, visit Sports Illustrated's medal count tracker.

For more on the Olympics, check out SB Nation's London 2012 Olympics hub.