Noisy earphones

I use Etymotic Research ER-4S in-the-ear earphones with my iPOD Nano when I walk, but it's annoying that the earphones transmit sound thru the wires/cord. I can hear anything that touches the cord. For example, when I walk, I can hear the cord thru the earphone as it rubs or bounces against my shirt or jacket. It's almost like there's a live feed thru the wire. There is no short that I know of. Could it be that the earphone plug is not grounded with the iPOD and that I need to use an additional jack to properly ground it?
it's a mechanical sound x-fer dude. you can only avoid it by not touching wires. i guess many folks who excersise with earphones hear wire tapping through their headphones.
I have found the shure IEM's to be quieter when exercising--but they all have some issues this way. Go to and read till next week about this issue and what people have found and preferred. At the gym, my shure 4c are the quietest I own.
There is a cord relacement available, IIRC, that addresses that problem. BTW, with the nanos, w/o an amp, you might be better off with the 4p(ortable).
Thanks much!