Brazil's Anderson Silva has revealed he will train until the day before Saturday's UFC bout with American Stephan Bonnar in a bid to maintain his strength in the unfamiliar light-heavyweight class. Silva, undefeated in the middleweight division since 2006, agreed to take on Bonnar at late notice after a series of injury-enforced withdrawals threatened the cancellation of the Rio de Janeiro event. "My preparation is going strong," Silva wrote on his twitter account on Monday night. "I'm only going to rest the day before the fight. I'm getting close." The 37-year-old's normal routine is to stop training a week in advance to concentrate on losing excess kilograms in the lighter 84kg category. The Bonnar clash will be Silva's third career fight in the 93kg division and comes just three months after he defended his middleweight belt with a second-round technical knockout of American Chael Sonnen.