What makes it so annoying to me is that a sprint implies putting in maximum effort for a short time. The pace of a sprint is unsustainable over more than a few seconds.

If you say you did "sprints" for over a year... no you didn't. Either you sprinted for a little bit and then had to walk for a while because you'd used up all your energy. Or, you jogged at a sustainable pace for a year and just called it a sprint.