I. Why You Need a Harness
In the early days of mountaineering, there were no harnesses. Climbers would tie the rope around their waist, and the belayer would increase friction around their own waist to provide protection. However, the drawbacks of this method were obvious: the ribs would experience intense pain due to the increased force, and this pain wouldn’t end when the climb was over—it would persist for some time afterward. Even worse, if a fall occurred during the climb, the consequences could be fatal. A fall with a force of 3.7 kN, which is considered only a moderate-intensity fall, could cause the climber to lose consciousness or even die within minutes due to the immense strain on the waist. Therefore, the two ultimate purposes of designing a harness are to withstand the impact of a fall and to distribute the force.
II. Design of the Harness
Nowadays, climbers all use harnesses for climbing, and the harness has become an indispensable piece of equipment. A typical harness includes the following design features: thickened and widened waist padding, leg loops, belay loops, and gear loops. With these features, descending, falling, or performing other operations while hanging on the rock face becomes much more comfortable and safe. Harnesses have also become more specialized: some are designed specifically for sport climbing, big wall climbing, or general mountaineering, but a truly high-quality harness will cover all these needs.
Design of the Harness
There are two most basic designs of harnesses: full-body harnesses and sit harnesses. When a full-body harness is under force, the direction of the force is perpendicular to the ground, pulling straight upward, which allows the force to be evenly distributed to the legs, chest, and back. This is its advantage. Its disadvantage is that in the event of a very violent fall, it may continuously rotate, causing dizziness for the climber and possibly neck injuries. Due to their high price and inconvenience in putting on and taking off, full-body harnesses have gradually exited the stage of rock climbing and mountaineering, and are now used more in industrial or adventure activities. Nowadays, sit harnesses are more widely used because, when paired with a chest harness, they can achieve the same effect as a full-body harness. The chest harness can also be replaced with a long sling. During mountaineering, the two shoulder straps of a backpack can also serve the function of a long sling.
Sit harnesses come in two designs: one is called the “diaper style” (which goes between the legs and connects to the waist belt), and the other is called the “Swami.”
To allow the two leg loops to function properly, wearing a diaper-style harness involves lifting the strap between the legs to connect it to the waist belt. This type of harness is gradually disappearing from the European and American markets for several reasons: first, it is very uncomfortable to hang on the rock face; second, it lacks a belay loop, requiring the addition of a carabiner; third, the force is concentrated and cannot be well distributed; fourth, the force points are dispersed, which can injure the legs and waist during a fall. This style of harness has undergone some modifications and is now specifically used for mountaineering.
The Swami-style harness is the most popular design on the market today. It was designed by Trailwise in 1967 and introduced by Forrest a year later. Although it has undergone many improvements since then, the core design of the harness has remained unchanged. When purchasing a harness, the waist belt design should be a key consideration, as hundreds of falls can exert significant force on the waist. A good Swami-style harness usually has a waist belt that is 8–11 cm wide at the back and 4–5 cm wide at the front, providing maximum comfort and safety for climbing or resting. The back of the waist belt doesn’t necessarily need to be wider—the wider it is, the better. In fact, a waist belt that is 8 cm wide but well-designed provides far better lumbar protection than one that is 13 cm wide but poorly designed.
III. Choosing Leg Loops
Leg loops can be divided into three types: non-adjustable, semi-adjustable, and fully adjustable. The back of the harness and the leg loops are connected using an elastic material. Non-adjustable designs are simple and lightweight, making them suitable for sport climbing. Nowadays, more people prefer adjustable harnesses. Semi-adjustable harnesses have an adjustment range of about 8 cm. Although they can be a bit tricky to put on, they feel very comfortable once worn and are convenient for movement, making them suitable for most people. Fully adjustable harnesses have an adjustment range of about 15 cm or more, so they can meet your needs at any time of the year without having to worry about fit. A good adjustable harness is also very comfortable to wear, though it may be slightly heavier.
Leg Loops
Regardless of the style chosen, a leg loop width of 6–8 cm is the most comfortable, especially for climbers with a larger body size. Leg loops narrower than 5 cm can feel as thin as a wire after prolonged climbing, which is very uncomfortable. The average weight of a harness ranges from 85–310 grams, which is not a significant difference. Unless you are engaging in extreme climbing, the weight of the harness is generally not noticeable when worn.
IV. Materials and Structure
Most harness manufacturers use flat webbing about 3 cm wide for the load-bearing parts. Using wider flat webbing to distribute pressure is a cost-effective method because it reduces manufacturing processes, but this can make the abdomen feel very uncomfortable. Therefore, some manufacturers use wide flat webbing at the back and narrow webbing at the front.
The first generation of padded harnesses either sewed a bunch of fabric into the flat webbing or filled tubular flat webbing with foam plastic. Although these two manufacturing techniques are still in use, they are now limited to the production of the simplest harnesses.
The current standard in harness manufacturing is the use of molded plastic. This involves pressing foam plastic between two layers of fabric, using a mold to cut this sandwich-like material, and then stitching it together with a computer-controlled sewing machine. This method results in a very snug fit. Some manufacturers vary the thickness of the foam plastic in certain areas or create air holes in the foam plastic using heat molding to improve air circulation.
For most harnesses made using the compression method, the stability of the plastic greatly affects the comfort, durability, and price of the harness. Squeezing the edges of the harness—if the soft parts cannot evenly distribute the pressure, they will quickly wear out. Better harnesses use slightly harder and more crush-resistant foam plastic.
The most worn areas of a harness are the rope paths—the loops where you tie knots. These areas are usually reinforced with additional materials. Higher-quality harnesses use durable fabric or double-layer flat webbing.
The exterior of the harness, especially the bottom of the leg loops, is also prone to wear. Therefore, some designs use DuPont fabric or flight suit material on the outside instead of ordinary backpack fabric to extend the lifespan of the harness. These smooth materials also reduce friction on the exposed thighs. Most compression-molded harnesses are finished with an additional layer of flat webbing on the edges, which can make them less comfortable to wear. The best solution (and possibly the most expensive) is to stitch internally, ensuring that the parts in contact with the skin are smooth.
The inner lining of the harness should be soft and comfortable, even when damp with sweat. While plush linings are very soft, this material does not dry quickly when wet and can easily freeze.
Structure
V. Wearing a Harness
Nowadays, the vast majority of harnesses on the market require you to double back through the belay loop when putting them on. However, there is now a buckle design that eliminates this extra step. The feature of this design is that whether you're putting on or taking off the harness, the buckle is always double-backed — you just need to loosen or tighten it.
Buckles are generally made of either aluminum or steel. Either material is fine as long as it has passed CE certification, so quality won’t be an issue — the scene in the movie *Vertical Limit* where a buckle rips apart won't happen in real climbing. Suppose a 100 kg person takes a 20-meter fall with a fall factor of 1.5, the force exerted on the buckle would only be 7 kN, while the standard strength of a buckle is 10 kN.
VI. Harness Maintenance
Many climbers wear harnesses that have faded and look old. While the age of the nylon has little effect on its strength, the industry does have certain criteria for harness lifespan: with moderate use, a typical harness lasts two to three years; with light use, around five years. It is also mandated that a harness must be retired after a serious fall, because internal damage may occur even if it's not visible from the outside. In addition, severe wear, seam splitting, buckle breakage, or even discoloration of the webbing are all signs that your harness should be replaced. So does that mean a harness over seven years old is useless? The answer is no — for example, in top-rope climbing, where there’s no falling, it can still be used.
The biggest enemy of a harness is acidic solutions. They can severely damage nylon without any visible signs. So never leave your gear in the trunk of your car for extended periods.
Many accidents involving harnesses stem from not double-backing — though the length of the double-back should exceed 8 cm to ensure maximum safety. To ensure you don’t make mistakes when wearing a harness, one of the most important methods is to avoid talking while putting it on. Also, no matter what, always perform a buddy check.