For someone who is able to maintain a consistent presence in the body and what they are doing rather than what they are thinking. This person is more practiced in mindfulness and is comfortable in an extended silence. Able to maintain a constant present moment awareness and go deeper into the present moment.
There are times in any meditation practice where you need the discipline of the progressive muscle relaxation to get that focus on the body, paying a concentrated attention to what the body is experiencing. Thoughts may come and go and that is part of the practice, however this meditator is capable of noticing those thoughts without attachment to them- They come and they go and they are just random thoughts, noticing them as something the body generates and that sometimes in a stressful moment, we can be engaged by the thoughts and begin to get involved in a story which engages emotion, however this meditator will notice that and allow it to be OK and then when the thoughts and the story disappear because the meditator disengages, they can go back to noticing what is happening in the body, focusing on any discomfort etc, being present to it until such time as it goes and then refocus again on the breath.
Enjoy.