In Chesterfield v. Johnson, 237 Va. 180, 376 S.E.2d 73 (1989), a water plant operator was walking up stairs when he realized he forgot to check a meter. He turned to go down the stairs and his knee gave way resulting in his injury. The stairs were not defective and claimant did not fall, nor did he injure himself by climbing or descending the stairs. The Supreme Court held that an injury resulting from turning was not compensable, even though the claimant was on the mission of his employer, because the work environment did not cause the injury.