Cotton is great for everyday wear, but for actually training or playing sport in these would get wet and heavy and then be less breathable.
Only medium left at this price but that works for me (y) hopefully not as skin tight as recent tracksuit bottoms I've tried!
I avoid artificial fibres getting in contact with skin for a longer period of time.
They're thinking fashion rather than doing sport in them (lol)
Do you make sure you train in 100% cotton?