Adjustment mechanisms, ladders incorporating same and related methods

A ladder comprising:

• a first assembly having a pair of inner rails and a pair of outer rails, the pair of inner rails being slidably coupled with the pair of outer rails;
• and
• at least one locking mechanism comprising:
• a bracket coupled with a first outer rail of the pair of outer rails,
• a lever pivotally coupled with the bracket,
• an engagement pin coupled with the lever and having an engagement portion sized and configured to engage an opening formed in the first outer rail and an aligned opening formed in a first inner rail of the pair of rails,
• a biasing member biasing the lever towards a first position, and
• a detent mechanism comprising:
• a slider body slidably disposed in a detent pocket formed within an interior portion of the lever,
• a detent spring disposed within the detent pocket and biasing the slider body in a first direction,
• a detent groove formed in a portion of the bracket, wherein when the lever is pivoted to a second position relative to the bracket, a portion of the slider body is biased into engagement with the detent groove by the detent spring such that the lever is maintained in the second position until a predetermined force is applied to a specified portion of the lever.