How common are gyms in Japan?

I am applying for a JET ALT position and see little reason to be rejected. My question is will I be able to work out in Japan? I lift 5-6 times a week and need solid facilities to meet my needs. Also how prevalent and accessible are training products such as whey protein and l-glutamine?

As a JET you are likely to be sent to a very rural area where there won't be gyms. In a city of any size there are gyms all over the place- usually one or more near any main station, but JET placements are very rural and can be extremely remote, to the point where there isn't even a supermarket in the area let alone a gym.

If you hadn't enviisoned being sent to such a rural area you might want to reconsider your application to JET.

The supplements you mention are available in gyms and sporting goods stores in cities.

I did understand that as a JET ALT it would be likely that I would be in a rural community but what about school gyms? Do schools (hopefully the one I'd be working in) have gyms facilities? I worked in several rural communities as a teacher here in the states and their gym facilities were at least adequate if not as advanced as I'd like.