The phrase "Top of the Rock" is an idiomatic expression that means to be at the peak or highest point of success, achievement, or prosperity. Full definition
Hope you're not standing on top of the rock looking around. (biggerpockets.com)
On top of rock climbing, you still need to continue to work on balance, cardio, flexibility and core stability, he says, so don't quit the gym yet. (womenshealthandfitness.com.au)