This 4-year study, conducted in seven elementary schools assigned to three conditions--Physical Education Specialists (PES), Trained Classroom Teachers (TT), and Controls (CO)--had two parts. The first investigated effects of a health-related physical education program on quantity and quality of lessons. Specialists produced the best outcomes, and TT were significantly better than nontrained peers. Part Two assessed maintenance effects approximately 1.5 years after intervention termination. Withdrawal of specialists significantly reduced the quantity and quality of physical education. TT maintained PES frequency but with a loss in lesson quality and a decline in student activity to 88% of intervention levels. Results support employing specialists and demonstrate the need for extensive professional development for classroom teachers responsible for physical education.