Answer:
The material emphasized by physical education teachers in their classes is influenced by trends and forces in society; as a result: coaches required to maintain certification.
Explanation:
Physical education interacts with other disciplines which is the reason why the coatches require to keep up their certification. It is related with health, with self-expression. Excercising also has a relation with psychologic effects, nutrition and so is important for a coach to be updated with all the innovations.
