As a teacher you have some control over your workload. Guidelines:
1) Don't give out more homework, quizzes, tests, etc. than you can/want to grade. I learned this the hard way as an English teacher. Try to pick a subject that is easy to grade and a manner that is easy to grade it.
1b) Don't give work a lot of weight/points. Students and parents don't get hyped up if they think an assignment is worth a few points. Even though percentage wise it has the same influence on their grade if everything you do does not carry a lot of points.
2) Plan at school. Grade at school. Taking things home is often a waste of time and seldom works as planned if anyone else is around. Don't create so much work for you and your students that you can't get it done at school.
3) Many teachers think their subject is important which often leads to too much homework, quizzes and tests for students. Lighten up their workload and you will be loved. Statistically, a good quiz will tell you as much as a good test about student understanding of the subject matter. A test just takes it out to a few more decimal points.
Training wise, I would train before and after school when I only had one child. Once I had two - five, I was down to training before school from 5-6:30 and then at work by 7. Weekends, summers and good time off at holidays can help with training and racing.
PS coaching helped me move from elementary to middle to high school positions giving me even more flexibility and exempted me from some dreaded faculty meetings.