Let's start with a quick history of Life Fitness. Four or so years ago they used to sell the Lemond spin cycles under their banner, then they switched to Keiser spin bikes. Then 2 years ago, after taking the best elements from the Lemond cycle and the best from the Keiser, they created the Life cycle GX.
From Lemond they took the heavy duty cranks. These transfer your pedal stroke power into the bike and the specialty heavy duty forged cranks are much more substantial on the Life...