Race Comment Explainer

Original comment with matches highlighted:

held up ion last, shaken 2 out, joined leader last, shaken up run in, led towards finish,

Matched phrases & meanings

Phrase	Meaning
Held up	Intentionally raced patiently at the back to save energy.
Headway	The horse was moving up through the field.
readily	The horse won easily, without having to be pushed to its absolute limit, suggesting it had more to give.
Rear	Running near the back of the field.

Summary

Intentionally raced patiently at the back to save energy.
The horse was moving up through the field.
The horse won easily, without having to be pushed to its absolute limit, suggesting it had more to give.
Running near the back of the field.