Here are some simple steps you can do to get the body that I have...
1. Walk from the U Prace tram station in Plzen to the Namesti Miru station because you can't find a tram ticket machine that works, carrying children part of the way.
2. Walk from U Prace to the main train station in Plzen because the trams are under construction, carrying children part of the way.
3. Walk from Horazdovice predmesti to Horazdovice (it doesn't sound like a long way, but it is), carrying children part of the way.
Do all this in one Sunday and, if you're like me, you'll be feeling stronger the next day!
In a way, this is actually more fun than working out at the gym.