What does "Go along the ground" mean? I couldn't find any source explaining it.
Context:
I got to the top FIRST. I've never ever won a proper race before. I'm hopeless going along the ground. I nearly always come last. But I can fly upwards like a rocket. I spread my arms when I was all alone at the top.
- A children literature. You can find that bit exactly here: https://fullenglishbooks.net/english-books/full-book-buried-alive-read-online-chapter-4