It simply means that you reached a certain “speed” and are maintaining that speed.
Take this example:
When you take a flight, the thrilling moment is when you take off, right?
Because of the acceleration.
Acceleration is what creates thrill and excitement.
Once you are in the air and travel at a constant speed, it feels normal. You eat peanuts and chat with you neighbour as if you were sitting at home, even though you are still travelling at 1000 km/hour.
When you originally start meditating, you often feel this sense of acceleration. You feel bliss, greater awareness, peace, etc.
Once you reach a certain level, these experiences feel normal. They are still there. You simply got used to these new spiritual states.
It does not mean that your spiritual development stops. You still travel at a certain speed but might no longer feel the original thrill and acceleration.
Makes sense, right?
To your Yoga!