It is more cost effective to work at home but you will have more focused at the gym rather than working out at home because if you're at home sitting on the couch you most likely won't want to get up and work out but if you force yourself to go to the gym once you already there you will work out more in focus more and you have more options for exercising at the gym since there are more machines
There is a growing concern over the physical fitness of children and adolescents because of growing obesity rates being the highest they've ever been I believe.