What is the burden of proving that a plaintiff sustained a serious injury in a motor vehicle accident?

The burden rests on defendants to establish by evidentiary proof, in admissible form, that plaintiff has not suffered a serious injury (Lowe v. Bennet, 122 AD2d 728 [1^st Dept. 1986], aff'd 69 NY2d 701 [701]). When defendants' evidence is sufficient to make out a prima facie case that a serious injury has not been sustained, the burden shifts, and it is then incumbent upon plaintiff to produce sufficient evidence in admissible form to raise a triable issue of fact as to whether plaintiff sustained a serious injury (see Licari v. Elliot, 57 NY2d 230 [1982]).