If you have some time and you want to try something more “sporty” try this cycle path Cyklostezka A2. I presume you don’t travel with a bicycle, but don’t worry, in Prague there are a lot of bike rentals.
In Prague (and the Czech republic) there are lots of paths you can ride, but I personally like this one, Cyklostezka – this path follows the right bank of the river from the city center (from National theatre) all the way to the suburbs and further on to the countryside. Along the way are lots of stands with refreshments and places to relax. The length of the path to Vrané nad Vltavou is about 20 kilometres (12.4 miles), and if you feel tired when arriving there, you can always take a train back to Prague’s Main station.
One tip – don’t forget to take your swimsuit, because during hot summer days there’s nothing more refreshing than jumping into the river.