OMG, my used-to best friend in primary school had his thumb like yours, I always wondered wtf is wrong with it when it goes like that – it's because of hypermobile joints! Mind blown.

Who wants to cycle instead? Cycling seems so boring and easy in comparison.

I do, but you probably guessed it, lol. I prefer cycling to running, just because it's a practical means of transportation in every day life, so I've done it more and therefore grown to like it more. I've done some running, but never consistently for a long periods. From experience I can say that it can be boring to cycle 10s of kilometers on a big highway, smaller ones have more variety and change, so they can feel easier on the mind (though constant up and downhill certainly isn't for the body!). I just realized that you live in Latvia where everything's flat, so I can understand if cycling there would be boring, but you can definitely make it hard – just cycle more and faster :P

I would imagine swimming being good form of exercise for hypermobile joints.