Self-rescue on a fixed rope with two friction hitches: setup, cycle, redundancy and the suspension-syndrome clock — plus a dry progression for the real thing.
A prusik ascent means this: you climb a loaded rope using two friction hitches. One connects you to the rope via your tie-in point, the second carries a foot loop. You weight them alternately, push the unweighted hitch upwards and work your way up centimetre by centimetre. Use case: a fall into free rope, a crevasse fall, retreating up a fixed line — whenever nobody can haul you.
Plain talk, because this is not a technique toy: the ascent is slow, exhausting and awkward to coordinate — and you perform it in exactly the state in which you are least capable of it: wet, cold, full of adrenaline and possibly with one hand that has stopped cooperating.
Then there is the clock. Hanging motionless in a harness can tip into suspension syndrome, a circulatory response that leads to fainting. A scoping review by international mountain emergency medicine (ICAR MedCom) calls suspension syndrome rare; in small hanging experiments 10 percent (fainting, 40 people) to 30 percent (pre-syncope, 20 people) of subjects had a circulatory reaction, and the timing was unpredictable from person to person — from a few minutes to hours [1]. The range is wide, the message is not: plan in minutes, not hours.
Plan on one course day for the procedure and on regular dry practice so it is still retrievable after two years without an emergency.
Checkable entry criteria before you rely on it:
The set has a fixed place on your harness, always the same one. In an emergency you do not search, you grab. Two cords, two locking carabiners, one foot loop.
Milestone: You grab the complete set blind, without looking, in under five seconds.
Both hitches go onto the loaded rope, the upper one higher than the lower. A pull test before every loading: does the hitch bite on this rope, in this wetness, with this cord?
Milestone: You test both hitches every single time without being reminded.
The upper hitch goes to your tie-in point with a locking carabiner — that is your safety connection. The lower hitch carries the foot loop. Length is decisive: with your foot in it, your leg must be able to extend fully.
Milestone: You hit the loop length three times in a row without readjusting.
Always the same order: stand up in the foot loop → push the upper hitch up → sit into the upper hitch → slide the lower hitch up. No hitch ever moves while it carries load.
Milestone: Twenty clean cycles without stalling and without a single glance at the sequence.
Both hitches stay on the rope and one is always load-bearing. There is no moment in which you hang from a single element.
Milestone: Your coach can stop the sequence at any point and you are still redundant.
The hardest metre is the last one: over an edge or into the station. Brute force does not help here — a foot loop set high enough does, plus a personal anchor you clip before you rebuild anything.
Milestone: You get over a simulated edge three times without your system ever hanging on one point.
This is the one skill in the series you hopefully never need — and precisely therefore the one that decays fastest.
For context: in the review of 210 North American climbing accidents in one year, 100 happened on the ascent and 46 on the descent (46 with the phase unknown) [3]. Self-rescue techniques are not only for the descent, but the statistics show the way down is no sideshow.
This guide explains and motivates, it does not replace supervised training. You learn self-rescue in a course, with a coach, under supervision and with repetition.
The number of wraps is not a constant, it is a decision you make on the day. The same cord that bites like a vice on your dry 9.8 mm gym rope with three wraps can slip on a wet, thin half rope — and conversely it can cinch onto old, fuzzy rope so hard you cannot release it.
So: test on the actual rope before every tour, at ground level, with body weight. Three wraps if it bites, four if it does not. The hitch you tested yesterday is a different hitch today.
For friction hitches of the prusik type Petzl names 6 mm cord [2]. Beyond diameter, grip matters: soft, slightly rough cord bites better than new, stiff material. And more important than any number: the test on the actual rope.
Three is the starting point. If the hitch slips in a ground-level load test, add a fourth. Wet, iced, thin or very slick ropes usually need more wraps. That is practice knowledge from instruction, not a standardised specification — which is why no number replaces the test.
Ascenders are faster, more comfortable and clearly superior on fixed lines. The prusik still wins on one point: it is always with you, because accessory cord hangs on your harness anyway. For self-rescue you plan with what you reliably carry, not with what is in the pack at home.
As fast as possible, but without errors. Hanging motionless in a harness can lead to fainting; in the ICAR review, small hanging experiments saw fainting or pre-syncope in 10 to 30 percent of subjects, with unpredictable timing [1]. Until then: move your legs, unweight the leg loops, start building immediately.
The sequence, yes — on a fixed rope near the ground, backed up, so a mistake costs nothing but frustration. The first time, though, have it shown to you and signed off in a course. Self-rescue is the skill where a small rigging error cannot be corrected in real terrain.