Lately after the Stuttgart-Lauf, I started again with jogging. I thought that it might be a good idea to have my iPod with me. I had it in my trouser pocket on the backside, as I don't like carrying things in my hand when jogging. After about half an hour, the iPod had some drop-outs which led it into a state where a soft reset was needed or a soft reset did no help and I had to wait until home to plug it into the power supply to do a hard reset.
Since then I bought a sports wrap to attach the iPod to my upper arm. Since I have the sports wrap, I had no more drop-outs on the iPod.
Of course, the iPod shuffle and iPod nano don't need this as they flash based and do not need to access a hard disk to load the songs into memory.