It's the 100th episode of The Biggest Loser,and this week, a balancing competition will bring the winner a coveted prize - a 24-hour visit from a loved one back home. Then the teams all take part in a tough challenge that tests their endurance, and later, one player will be sent home from the team that falls below the dreaded yellow line.

This week brings a shake-up no one sees coming when all of the contestants are divided into just two teams - blue and black - leaving many players without their original trainer. Drama ensues, especially with one team who struggles to get used to their new trainer. And contestants are put to the test with one of the longest challenges ever, in which each team tries to put as many miles as they can on their bike in a 24-hour period.