I run with a small (16 litre) backpack. Inside it I have the following:
Wallet with a little money and my travel pass, phone, headphones, house keys, buff and a 500ml bottle of water.
It’s sort of ok, but on longer runs it bounces about a lot and the straps begin to move around. I've seen other runners with specialist packs that are designed for running. I found one on Amazon that looks ok..
amazon.co.uk/dp/B076892YRV/...
Does anyone use something like this? What do you think?