How much time can a student have out of classroom engaged in other activities (e.g., sport teams) before it has a detrimental impact on their learning that outweigh the positive impacts of extra curricula activities?

All of us like to protect our “time” in teaching and maximize student time in learning. Successful time is more related to engaged and productive time and not spent time. When we consider that 70-80 percent of our classroom time teachers are talking then the productive and engaged time it is very low indeed. Maybe we need to reduce “our” time and increase “their” time. Consider sport (etc.) many students see the purpose of schooling in these terms, derive much satisfaction and learning, and the art is how we integrate and capitalize on these activities in our class time. For some students little outweighs the positive impact of these extra curricula activities so we need them indeed. The key for the classroom teacher is productive time – how could you construct a program of study (with clear learning intentions and success criteria) for learning in interrupted time periods.