Answer: Challenging because they have greater needs for large-muscle activity, which has become an even greater challenge in schools with reduced recess time.
Step-by-step explanation:
As males grow they find that they develop muscle mass fast and as a result need to train these for the most part. This is a challenge for them because they will have to get involved in large-muscle activities whilst also engaging in academic activities as well which can be strenuous.
This can be an even bigger challenge in schools with reduced recess time because it means that the boys will have less time during the school days to engage in such activities and they will have to compensate for this time elsewhere which will leave them with less time to rest.