Should I push my 9-year old son to participate in sports or activities?

My son would stay indoors and watch tv and play video games for hours and hours and never leave the house if I permitted it. He doesn't enjoy school and lately doesn't really want to participate in any activities that require any effort. It's making me crazy! Any ideas? I'm on the verge of simply making him play a sport or some other activity but I'm unsure about it.