Myth #9: Walking on rope damages it.
Truth: Not unless you are wearing ice crampons or razor blades. There is even recent discussion that claims crampons in snow just pass through the rope fibers and cause no harm to the rope.
Jim Kovach, in an exhaustive 8 month study in Ohio, and reported to/by ITRS (International Technical Rescue Symposium) including using rope as a doormat for months, and then driving over the same rope while it lay on beds of broken chards of bricks and a glazer’s pile of broken glass. Then the rope was pull tested! Although the kernmantle showed minor signs of wear, in testing no loss of strength was seen. There is no evidence that stepping on a rope will grind dirt past the kernmantle into the core.
Personal proof: Cut about 1 foot off an old very used rope and examine the core of the rope yourself.
In other testing done by CMC out of California, rope were immersed in various substances for long periods of time and then tested. Some of these included paint, tar, sap, gasoline, oil and vomit. Most of the test items, including gasoline and oil, did not cause strength problems (although an oily rope is tough to use, it did not weaken the rope). Acidic materials, like vomit and animal urine, can cause a 30 percent or more strength reduction.