I bought a 3-pack of these to wear when I use my stationary bike, as I find that regular panties dig into my skin, when I ride.  These are light weight, comfortable and fit as expected. (Buy your regular underwear size.). They do not ride up my legs when I ride.  Most women wear these to keep their thighs from chafing, when wearing a skirt with no pantyhose and I would recommend them for this use as well.