(a) Any person employed in the public school system of this Commonwealth who has completed ten (10) years of satisfactory service as a professional employe or member of the supervisory, instructional or administrative staff, or as a commissioned officer, of any board of school directors, county board of school directors, or any other part of the public school system of the Commonwealth, shall be entitled to a leave of absence for professional development or a sabbatical leave for restoration of health or, at the discretion of the board of school directors, for other purposes. At least five consecutive years of such service shall have been in the school district from which leave of absence for professional development or sabbatical leave for restoration of health is sought, unless the board of school directors shall in its discretion allow a shorter time: Provided, however, That in the case of professional employes of area career and technical schools or technical institutes prior service in the participating school districts shall be credited toward such service requirement. A leave of absence for professional development or sabbatical leave for restoration of health shall be for a half or full school term or for two half school terms during a period of two years, at the option of such person: Provided, however, if a sabbatical leave is requested because of the illness of an employe, a leave shall be granted for a period equivalent to a half or full school term or equivalent to two half school terms during a period of two years: Provided further, That if a sabbatical leave for restoration of health or a leave of absence for professional development for one half school term or its equivalent has been granted and the employe is unable to return to school service because of illness or physical disability, the employe, upon written request prior to the expiration of the original leave, shall be entitled to a further leave for one half school term or its equivalent: Provided further, That if a leave for a full school term or its equivalent has been granted and the employe is unable to return to school service because of illness or physical disability, the board of school directors may extend such leave for such periods as it may determine but not to exceed one full school term or its equivalent. Thereafter, one leave of absence for professional development or a sabbatical leave for restoration of health shall be allowed after each seven years of service.

(b) A sabbatical leave for restoration of health or a leave of absence for professional development granted to a regular employe shall also operate as a leave of absence without pay from all other school activities.