Git hook commit similar to subversion start-commit hook

Hello,

Is there any hook in Git similar to start-commit subversion hook? The
requirements would be:

1- A hook on the server side (as pre-receive)
2- It will execute the actions *before* the begin of transaction
(pre-receive hook needs the references already pushed before).

For example, it would be useful to refuse a push if the server has a
high load.

I have read man githook, but there is nothing similar.

Best regard, and excuse my poor english.