I'm gonna throw this in because it needs to be added. It's not an 'answer' but it's related to the others here as a supplement, and it's an absolute golden Best Practice that absolutely should be performed on every single SharePoint Content Database that you manage.
Once you release the free space from a truncated LDF after a Simple Mode backup to do whatever movement of the files that you need to - PREGROW ALL FILES BACK TO WHAT THEY WERE, OR WHAT YOU CAN AFFORD TO DO SO.
When SharePoint content gets added or delete, or even updated, SQL Server will populate the MDF and LDF files (the ratio of which depends on your recovery model set on that particular database). SharePoint does this a lot, especially with busy sites.
When you start using a SharePoint site straight after releasing the freespace, the LDF/MDF files for the database start to get written to. Because they're technically maxed out (because you shrunk them), SQL will grow the files automatically depending on some setting (usually increase by 10% or, at it's worst configuration: 10MB).
This growing has a performance penalty. A pretty noticeable one too.
So, if you shrink your files, the database will claim back that space over time anyway, and it WILL slow down the site for your users as it does this. Give them that little bit of experience bonus and save SQL from autogrowing.