Any school board, upon written request, may grant a leave of absence to a permanent certificated employee for such reasons as the school board deems appropriate, including, but not limited to, study, military service, or professional improvement or because of physical disability or sickness, or as otherwise required by law, subject to such rules and regulations governing leaves of absence as may be adopted by the school board. A school board may require a permanent certificated employee, because of physical disability or sickness, to take a leave of absence for a period not exceeding one year. In any such case, the procedure to be followed and the rights of the permanent certificated employee shall be the same as those prescribed in sections 79-824 to 79-842 for termination of a permanent certificated employee.