I read the articles referred to here several weeks ago, and agonized over having to give up my new-found love of TR soloing... But soon realized after reading the specifics of the testing methods that I needn't worry. Here's why. When climbing ANYTHING with ANY TYPE GEAR under ANY METHOD (sport/trad leading, TR belaying, TR soloing etc) you MUST be considerate of the loads you will put on EACH PIECE of your gear at ANY POINT in your system. You want to limit your fall distance as much as possible to prevent undue stress on your protection/gear/body. This applies to the above mentioned testing, as the testers eluded to.
I've seen several people (on ice and rock) attach their USHBA to a locker, and the locker to their belay loop. As they climb, the device slides along the rope but hangs below their crotch, close to mid-thigh level, because the locker dangles from the bottom of the belay loop, and the Ushba dangles below the locker. When they fall, the USHBA does not move on the rope, but in order to catch the fall, 4 things happen. 1) as you fall past the Ushba, the locker slides from the bottom of your belay loop to the top (about 6 inches by the time you consider a 4 inch belay loop plus harness expansion, etc), 2) the locker must reverse it's direction as it catches on the top of the belay loop (goes from hanging at the bottom of the belay loop to catching at the top and pointing up) (about 6 inches), 3) the Ushba must rotate to lock (again it doesn't move on the rope, but rotates on the rope) (rotation results in a loss of about 2 inches in my experience), and 4) the rope stretches, dependent on the amount out, percent of rope stretch (varies by manufacturer), and age of the rope. If a fall occurs, the body falls a MINIMUM of 14 inches.
Will this distance damage the Ushba / rope? I haven't seen it happen yet, even with a 180#-plus guy falling well OVER 14 inches before it caught him. But it is best to limit the fall factor if possible, and here is how I do it:
I use a zip-tie to secure the locker to the top of my belay loop. I clip the locker in, pull it straight up, and then wrap a zip tie horizontally around the belay loop just below the locker to keep it at the top of the belay loop. This accomplishes 2 things: 1) the locker doesn't have to slide up the belay loop before it catches me, because it is already held at the top, and 2) if it is snug enough, the locker never inverts. At worst, it lies horizontally toward the Ushba (instead of pointing down toward the Ushba). So I fall about 5 inches (minimum) (locker rotation from horizontal to pointing up, and 2 inches with rotation of the Ushba). That's 9 less inches for my falling body mass to build energy to transfer to the system. This minimizes the fall factor, thus minimizing damaging the device or rope.
So... we can't change rope stretch (#4) or the amount the Ushba rotates on the rope (#3), but we can affect #2 and #1.
As with any statistic, in order to use the results correctly, one must understand ALL of the aspects of the research methods utilized (and those not utilized) and know what the applications were intended for. Read the Lyon's report (link above) for yourself. The Ushba was not tested as an "ascender" but as a "backup device" (something to arrest a significant fall) Our fall of 14 inches (or much less, say 5 inches) compared to over 72 inches (Lyon's testing used a one meter lanyard with 220 pounds dropped on it (!) equals a 2 meter fall, over 6 feet!!!) which is a long way to fall on any device. And 3 out of 4 ropes used in testing were considered "low stretch", and only one dynamic. So does this British study, although very well executed, apply to TR soloing? Not in my mind, if rigged properly.
If you are new to TR soloing, or want to try it, talk to people that do it, and watch them. Additionally, there are at least 4 considerations as a TR soloer you must attend to:
1) besides assuring a sound redundant anchor system with no extensions, you must protect your rope at the top. If it runs over any edge that isn't perfectly round and smooth, protect it. Sometimes I use my truck floor mat.
2) you MUST weight the rope at the bottom with something to keep the rope below you from being pulled up as you climb. Some people duct tape a rock to a sling and clip this into a knot at the bottom of the climb. I use my rope bag with the rest of the rope secured inside, tied off about 2 1/2 ft above the ground.
3) always test your self belay device by weighting it before you begin climbing to assure it is oriented correctly and locks up.
4) climbing alone, there is no one to double check your setup, harness, etc. TRIPLE check your stuff, starting from one end and going to the other.
People ask me: How can you trust just one piece of gear? Well, we do it all the time belaying with one GriGri or ATC.
How can you trust just one carabiner? We do it all the time belaying with a GriGri or ATC.
I love it because I never have to worry about my belayer being inattentive... the Ushba is always right in front of me.
And actually, I am a social climber, it's just that sometimes my climbing partners can't go. Now they're annoyed with me for getting more climbing time in than they are!