Harness Comfort

[MyUserID 0]

Hey everybody,
Alrighty, I'm currently working on a project for my ergonomics and biomechanics class at school, and I figured I'd choose skydiving harnesses as my topic. Basically, the whole idea behind the project is that we're suppose to find an existing product, and then evaluate the ergonomics behind it, and try to recommend modifications. I figured that the leg straps on the harness could use some modifying because they can become a bit uncomfortable at times and sometimes make your legs fall asleep on ya while undercanopy. Well, the only thing that me and my group members could see as a way of making them more comfortable, would be to increase their surface area. However, just making the straps wider could be quite combersome. We came up with an alternative concept (Just a concept, no specifics yet) We thought about maybe having some pads that extend from the existing leg straps down the back of the thigh. The pads would be made so that they would not be intrusive as far as walking and freefall is concerned. I guess made out of some stretch material. These pads would be secured down by the knee by a strap of some sort that goes around the thigh. From this strap would extend a long strap that would travel up to..eh, i guess right below the three ring system and would go through some sort of adjustment mechanism there. This adjustment mechanism would also have some sort of quick release on it. Okay, are you still with me here? Basically, the concept works like this, during freefall and walking, the pads are just there, attached to the backs of your thighs. Once you are under canopy, you pull on the straps that go through the adjustment mechanism under your three-ring, and it turns your harness into a seat. Then, I guess right before you start your downwind run, you would release these straps with the quickrelease mechanism to allow your legs back down to a standing position, and would land as normal.
Now, keeping in mind that I'm just some nobody undergraduate student who doesnt work in the parachute industry and only has a few jumps under his belt, what do you guys think of this concept. Yes, I'm already seeing problems with water landings and stuff if one didnt undo the straps around the knees, and no I dont know how the adjustment straps would be routed up the harness to the adjustment mechanism, but aside from that, what is your feedback. Also, if you dont like this idea, could you recommend something else? Any suggestions would be greatly appreciated.

[GrumpySmurf 0]

"We thought about maybe having some pads that extend from the existing leg straps down the back of the thigh."
Why do I have images of the marketing campaign involving, "Introducing the Javelin II/Mirage G4/etc ..... with wings!" :)

[LawnDart21 0]

Here's an idea: Alot of freeflyers (myself included) have bungy cords sewn between our leg straps to keep them from sliding down to our knees while sitflying. Second, your worry is making the leg strap too cumbersome, so perhaps instead of enlarging the leg strap, just reshape it. If a standard rectangular leg pad is 20 square inches, change the design of the rectangular pad into say an oval or an ellipse, or a "1/4 moon" shape, there by placing the bulk of the padding in the more needed area (the back of leg/butt area) and less padding at the connection to the ring/liftweb. You'd be using the same surface area of padding, so it shouldn't be that much bulkier around the leg. Then encorporate the bungy connection of the two leg straps. Anyways, I was a marketing major in college, so ergonics was never really my thing, take it for what it's worth. Good luck with the project.
"Gravity and Ground, neither one gives a sh*t."

[riggerrob 558]

Great minds think alike!
A "nobody undergraduate" and the French military-industrial-complex both came up with the same concept.
Your idea has already been tested.
Back around 1997 a French research & development corporation mentioned a similar leg strap configuration for military HAHO (High Altitude High Opening) jumpers. These extreme users typically open at 25,000' or 30,000' and glide downwind for 30 minutes or so. Thirty minutes sitting in the same harness combined with freezing air and poor circulation are gaurranteed to give you a numb bum.
This experimental French harness closely resembled your concept except that the second set of French leg pads were worn loose, outside of the original leg pads. After opening, the user was supposed to slide the extra leg pads towards his knees, then adjust buckles just below his 3-rings.
Another radically different idea was patented by a Quebec inventor and used by U.S.Army HAHO jumpers. This idea is beautiful in its simplicity. The U.S.Army jumpers simply tied a couple of yards of cord to chest rings. After opening, they released the cord from its rubber band stowage and STOOD on the cord. This method transferred the load from their thighs to their boots.
Another problem is that leg pad design is highly subjective. Pads that are comfortable on skinny people are uncomfortable on fat people and vic versa. For example, many people with wide thighs swear by double-wide leg pads.
On the other hand, people with skinny thighs - like me - often find double wide leg pads uncomfortable because the hard, bound inner edge rubs against our "naughty bits". I am far more comfortable with narrow, rounded edge leg pads. If you want to see rounded edge leg pads, look for pictures of Rigging innovations Telesis 2, Genera and some Talon 2s.
Finally, consider the latest generation of tandem student harnesses. These harnesses are a noble attempt to make "one size fit everyone." They differ from previous generations of harnesses in that they are supposed to be adjusted so that students are suspended from the front of their thighs and hang in the harness with their thighs horizontal, this helps them raise their feet for landing and reduces the incidence of sliding in on the student's face.

[rmsmith 1]

In the early eighties I was a high-rise window washer. As the design of buildings became more difficult to access, I had Ray Ferrell configure a narrow boatswain seat with leg and waist straps. It allowed me to sit in comfort on the board, or slip forward into the legstraps to climb into a difficult-to-reach locations. Many people wanted to know were I had purchased this gear. Ray was rigging out of his loft in Alameda, CA at the time, but I never gave away the information. I continued to contract the difficult jobs that paid the most money.

[MyUserID 0]

Thanks a lot guys. I guess now I could go and look into the advantages and disadvantages of all of those different designs. If anybody has their own ideas, or thoughts about harness comfort please let me know, such as other things you would like to see changed on rig harnesses to make them more comfortable/ safer...etc. Also, if anybody knows where I can find more information on those other designs, let me know.

[Jimbo 0]

Paragliders or Parasailers, whatever they're called they stay up there for longer than most skydivers. I'm guessing that those rigs have special comfort options built in. Maybe some research there would be helpful.
-
Jim

[skybytch 259]

You might contact the various sport container manufacturers and talk with them about harness design. In many cases, you'll be able to talk directly to the person who designs their harnesses - the skydiving industry is basically a cottage industry, and the people behind the ideas are usually still the ones running the companies, and I can almost guarantee that they are all super nice people.
A good one to start with would be Sandy Reid at Rigging Innovations (Talon, Voodoo); they were the first to come out with hip and chest rings, which imho make a LOT of difference in how comfortable a harness is. Another to talk with is John Sherman at Jump Shack (Racer); they've been making a comfortable harness for years, even before harness rings. Relative Workshop (Vector) too; they've been around for a long time cuz they're doing something right - Vectors also have very comfortable harnesses.
Good luck on the project - and on the rest of your student jump! pull and flare,
lisa

[riggerrob 558]

LawnDart21 had the right idea about eliminating some of the padding near the hip joint/hip ring and shifting that padding to a place where it will do more good.
Since most hip junctions are flat, and most hips are almost flat, there is little need for padding in this neighborhood.
On the other hand humans are sharply curved bottom dead center of their crotchs and few have much fat or muscle to protect the ligament on the inside of the thigh, you know, the ligament that attaches to the muscle that pulls your thigh inboard.
So padding is most important in the crotch.
On another concept, if you get the harness geometry correct, you can get by with very little padding.
Please let us know how your school project turns out.