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Ergonomics

THE SCIENCE OF DESIGNING EQUIPMENT THAT WORKS BEST WITH THE HUMAN BODY


We have a long term fit fixation: an obsession with designing and refining all the parts of the pack to best fit the widest range of body sizes and shapes.​ Each body-contact part of the pack needs to be precisely shaped to create a mirror image of this part of your body. Otherwise pressure points will be created leading to discomfort or pain. The spacing between the parts: hip belt, shoulder harness and backpanel must match the dimensions of your body. The body contact parts must also be positioned to softly transfer the load onto the bone structures of the body and avoid transmitting the load onto the muscles.​ Forty years of designing packs has allowed us to develop the simplest systems to precisely fit the widest range of body forms. We use multiple sizing and unique auto-moulding and custom-shaping technologies.

The key components are:
  • All models except our smallest daypacks have adjustable back-length. 
  • Most models also come in two backlengths, S & L.
  • The backpanels on all our packs auto-mould or custom-mould to your back shape.
  • Shoulder straps auto-mould to the slope of your shoulders.
  • They come in 3 styles depending on load requirements, and the larger packs have shoulder straps in 3 sizes.
  • Pelvic-Form hipbelts in 3 sizes with adjustable curvature and length and auto-moulding over the top of your hips.
  • Smooth and continuous transitions between harness parts.
  • Shoulder straps, hipbelt and backpanel are all highly breathable to minimise heat build up.
BODY FRIENDLY - ACHIEVING THE PERFECT FIT
FORM FITTING BACKPANELS


When checking other brands of pack, avoid models that concentrate the load by having separated padded areas and gaps in the backpanel or between harness parts. Thick padding in the backpanel does not necessarily increase comfort and moves the load farther away from your back. Especially avoid packs with a ventilation gap in the small of the back. Even if the pack frame is bent to the right shape, your back tends to round out into the gap towards the end of a long day due to fatigue, magnifying the spinal distress caused by the offset load.

Our pack frames bring the load as close to your back as possible while maintaining an air gap for back ventilation and preventing the contents of the pack touching your body. The suspended backpanel auto-mould to your back shape. On the large models the tension on the mesh backpanel can be adjusted for the optimum air gap.



X-FLOW

X-Flow chest straps eliminate the pressure and breathing restrictions of a conventional sternum strap, lightly disperse the load over the whole chest area for the greatest comfort and lock the pack close to the body for the greatest stability. When Balance Pockets are used the sternum straps connect to the opposite side Balance Pocket to form the X flow system. These straps naturally lie clear of your chest. If not using Balance Pockets, you can clip on the optional accessory X-Flow straps.

PACK SELECTOR

SHOULDER STRAPS WITH U & V FLOW

These shoulder straps are used on our small to mid-volume Ultralite family of packs. They are made of Mono Mesh, custom specified for shoulder strap use with these outstanding characteristics:

•Air permeability •Heat exchange •Shock absorption •Resiliency •Optimised Stretch •Low weight.

This stretches over the shoulders, auto-moulding to the exact slope of your shoulders.

On models with X-stays and adjustable backlength, a clip at the base of the shoulder straps can be positioned at different heights in a series of slots sewn to the pack behind the back panel.

On models with 3D frame sheets or Perimeter frames, the shoulder Straps have On-Adjust buckles so that you can fine tune your backlength with the pack on.
AUTO-FORM HIPBELTS

These are used on our larger daypacks and light mid-volume packs. They use a twin web, dual adjust system to achieve a precise fit. The top webs go around your waist and wide lower webs go around the top of your hips. The tensioning webs connect to top and bottom adjustment buckles via one webbing loop, forming an easy to grab handle to tension the hipbelt. By adjusting the relative tightness of the top and bottom webs you can mould the hipbelt precisely to your hip shape, while automatically moulding the backpanel to your back shape!
PELVIC-FORM HIPBELTS WITH U FLOW

These are used in our big packs. While the pelvis is a great load carrying structure, the hipbelt must be exceptional in design to take heavier weights without causing bruising over your hipbones or pressure on your hip sockets. Our large hipbelts are the result of many years of development and refinement.

Sizing Our Pelvic-Form hipbelts come in 3 sizes to cover the whole range of pelvis sizes. Each has three parts, a central base and two ends. The 3 parts join together with velcro. You can micro-adjust the overall hipbelt curvature and the length by changing the velcro overlap.
Auto-Moulding Like the Auto-Form hipbelts, our Pelvic-Form hipbelts have separate top and bottom tensioning webs to the center buckle to distribute the load over the widest area. In addition, Pelvic-form hipbelts use a 2:1 pulley system to allow easy tightening with heavier loads. The tensioning webs connect to top and bottom adjustment buckles via one webbing loop, forming the same easy to grab handle to tension the hipbelt. By adjusting the relative tightness of the top and bottom webs you can mould the hipbelt ends precisely to your hip shape.

FITTING MEN AND WOMEN
We don’t make separate mens' and womens' packs. We believe it is marketing hype to say one shape fits men and another fits women. This is because there is as much variation in the shape of backs, shoulders and hips within each sex as there is between sexes. The ideal solution is complete adjustability so you


can achieve a mirror image fit to your unique size and shape, whether you are male or female. Chest shape is where men and women differ. We have 2 sorts of chest straps, Sternum straps and X Flow straps to cater for all chest shapes. Big-breasted women will prefer Sternum straps.

WHY OTHER PACKS INCREASE BACK PAIN UNNECESSARILY
The common internal frame system, twin vertical stays, fails to prevent the backpanel rounding out to a convex shape horizontally when packed (A). Therefore the side profile of the pack is deep so that the load is positioned farther from your back. This increases the leverages on your shoulders and back, the forward stoop and the back strain.
Suspended mesh backpanels (B) have become popular in recent years. Many of these push the load far from your back, increasing forward lean. (see picture)
An improvement in load distribution over these systems is achieved by using a plastic framesheet to keep the backpanel flat horizontally (C), bringing the load closer to your back and reducing the leverages.
WHY AARN PACKS ARE BACKSAVERS (EVEN WITHOUT BALANCE POCKETS)

We use 3 systems to bring the load closest to your back. X-stays are used on our small top opening packs, while a 3 D shaped frame sheet is used on our small panel opening packs. On our large packs we are revising the shape of our perimeter frames this year to an hourglass shape which allows us to reduce the length of connecting bars to save weight. All 3 systems create the concave backpanel shaping and the narrow side profile (C). The slimmest side profile means the most upright posture and the least back strain.
This is why our packs appear bigger when viewed from behind but slim when viewed from the side. Of course you won’t find any large pockets or clip-on daypacks on the front of our packs farthest from your back, the worst position for load carrying comfort! Daypacks used for both walking and cycling need to hug your back, yet be flexible in the vertical direction to fit the straight back of walking and rounded back of cycling. Our daypack frames frames are flexible in the lower back panel to allow this.The hipbelts nicely pull the backpanel into your lumber back curve to maintain back support.

TESTIMONIALS


“The wide shoulder straps are comfortable, pliable, and not bulky. Some of the most comfortable I’ve ever worn.”
Ryan Jordan. Review, backpackinglight.com.

"The shoulder straps were gently contouring and I experienced no neck pain, which has been a constant feature of my pack carrying life."
Paddy Pawson, Waipuna Community Trust, Christchurch

"This pack has many adjustments and while initially I needed to sit and work it out, the pack can be custom adjusted to fit any person’s frame size."
Paddy Pawson, Waipuna Community Trust, Christchurch

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