Race Comment Explainer

Original comment with matches highlighted:

held up towards rear, along 5th, throughout, pushed along 5th, behind from 9th,

Matched phrases & meanings

Phrase	Meaning
Pushed along	The jockey started to urge the horse (hand-riding, not necessarily using the whip).
Towards rear	Running near the back of the field.
not fluent	The horse jumped the tenth fence/hurdle poorly or awkwardly
tailed off	A definitive statement that the horse was finished and effectively out of the race
Held up	Intentionally raced patiently at the back to save energy.

Summary

The jockey started to urge the horse (hand-riding, not necessarily using the whip).
Running near the back of the field.
The horse jumped the tenth fence/hurdle poorly or awkwardly
A definitive statement that the horse was finished and effectively out of the race
Intentionally raced patiently at the back to save energy.