Last year we had some guys from the Canadian track team in the tunnel and one guy had a few pairs of custom shoe covers, of different fabric to test. Some of them were worse than no covers at, all.. But they were all very tall, which I remarked on. He mentioned that there was a rule about how high covers/socks can be. I figured it was so that guys didn't find an aero fabric and cover their entire legs in them, not compression gear.
