Pick teammates who make you run the extra lap, not the ones who help you skip it.

The people you spend time with set your normal without either of you discussing it. A group that makes the higher standard ordinary pulls you up quietly, and a group that makes skipping easy does the same in the other direction, just as invisibly. This is not about their character, it is about what becomes unremarkable when you are together.

Look at who you are with when you do your best work and arrange to be around them more. Choose the training partner who is slightly better than you. And notice where your standard drops without anyone deciding it should.