Before the Supreme Court held in Markman v. Westview Instruments that claim construction is an issue of law to be decided by the judge, and not the jury, parties would often build alternative theories of infringement and invalidity into their contentions and expert reports to take into account the different claim construction positions being argued. Because they couldn't know which position would be accepted, they were forced to plan for both, and present theories under both at trial.
Markman changed that practice. Now that claim construction is almost always decided before trial (and usually before expert reports), parties can focus on the judge's construction while building their trial presentation. However, it is worth remembering that pretrial claim construction is not set in stone, and that the judge can modify that construction based on any number of inputs, including the evidence at trial and the parties' evolving arguments.
Judge Noreika did exactly that in a ruling issued earlier this week, leading to a non-infringement finding for the defendant, and eliminating the need for a post-trial opinion on the evidence and argument submitted during trial.