In Circle K Store No. 1131 v. Industrial Commission of Arizona, 165 Ariz. 91, 796 P.2d 893 (1990) and Hypl v. Industrial Commission of Arizona, 210 Ariz. 381, 111 P.3d 423 (App. 2005), the supreme court explained that courts in other jurisdictions have taken three approaches in addressing the "arising out of" requirement in unexplained fall cases. Id. at 95, 796 P.2d at 897. Some courts allow an inference that the claimant's fall arose out of the employment if the claimant can show that no idiopathic condition caused the fall. Id. Other courts require the claimant to show a causal connection between the injury and the employment. Id. The majority of courts, however, embrace the positional-risk doctrine in unexplained fall cases. Id. at 95-96, 796 P.2d at 897-98. Under this doctrine, the claimant is not required to exclude idiopathic causes. Id. at 96, 796 P.2d at 898. If the claimant can establish that the injury occurred "in the course of" the employment, a presumption arises that the injury also "arose out of" the employment. Id. The court in Circle K adopted the positional-risk doctrine for unexplained falls: An unexplained fall is a neutral injury, one neither distinctly personal to claimant nor associated with the employment. We hold that in the case of a neutral injury, the positional-risk doctrine applies. In this case, claimant would not have been at the place of injury but for the duties of her employment. . . . Consequently, a presumption arises that her injuries "arose out of" her employment. We reach our holding keeping in mind the policy of construing the Worker's Compensation Act liberally with a view of effectuating the principle of placing the burden of death and injury on the industry. In addition, because fault concepts have no bearing on whether or not worker's compensation should be awarded, an employee should not have to explain how an injury occurs, as long as it occurs in connection with her employment. Id. Circle K provides the legal foundation for our decision in this appeal. Additional support is provided by Hypl, 210 Ariz. at 387-88, PP20-21, 111 P.3d at 429-30, in which this court recently applied an unexplained injury presumption. Claimant Hypl was transporting a load of wire from Nogales, Arizona to El Paso, Texas when he was observed driving erratically on Interstate 10. Id. at 383, P 2, 111 P.3d at 425. He was arrested and medically examined. Id. at P 3. He had a skull fracture and underwent emergency surgery. Id. At the ICA hearing following denial of his workers' compensation claim, he testified that he remembered loading his truck and driving toward Interstate 10 but then had no additional recollection until he awoke from the coma following his surgery. Id. at P 4.