Recovery is right, and I'm not lecturing here, but there is a right way and an easy way, and as one who has worked rigging for cargo handling, marine towing and salvage and other things I'd rather not say as they were in my younger and more "invincible" days when watching the steam off a line was 'cool and seeing if you could get the "tattletail" to stretch was fun. Those things can and will get you hurt of worse. If you're going to be "jumping" on the line, you want to do some research on your own. Some 'big ole tugboat line' could be deteriorated seriously inside, and if you don't look or know how, you could lose a buddy, his leg or the rear of your rig.
You can go on line and find charts for the breaking strength of various lines and straps, but that is for NEW stuff. Not "PRE-STRESSED" or "lightly used", better known as abused stuff. Some of the new "polysteel" and other more sophisticated lines take alot of abuse, but do yourself and those around you a favor. Start with NEW, or at least new old stock that hasn't laid about mildewing or getting dirty or contaminated with dirt or worse, metal chips. They all cut fibers, fibers make yarns, yarns make strands, strands make lines. Be safe doing it. And good luck.