Body Mass and Pack Weight

[abowen]

Interested in hearing views or ideas from others regarding pack weights and body mass. I know that it is mostly recommeded that pack weights for multi day walks be a maximum of about 1/3 of your body weight. My own pack is generally about a 1/4 of my weight. I can live and survive comfortably out of this for several days.
My particular interest is in what weights smaller people generally carry - in particular smaller women. I often hear comments that they would be interested in longer walks but the pack weights generally scare them off. Is thetre an optimal weight range to be a good multi day walker? Can someone who is say 50 kilo's in weight get their pack weight down to 15 to 16 kilo's and have sufficient gear and food for four of five days? Does sharing equipment help to reduce the load? Are smaller sized sleeping bags, clothes, etc. significantly less weighty - can this make a 2 to 3 kilo difference when all combined?
Interested in what others have to say.
Cheers
Andrew

[Julafreak]

hmm.. Im a small man. Even tho Im in my twenties (haha Asians are generally small farts) Weighing only 65 kilos. Multi day walk with a heavy pack spoils the mood sometimes. Max I ever carried is 18 kilos and that was only for 4 days. Sufficient everything except that I could do with more warm clothing. I cant imagine how it would be for walks more than 4 days. Im considering getting a better pack. Maybe the pack harnesses system is a huge factor in comfortability?

[Ent]

At the 108 kilogram range I find twenty-five kilograms reasonably ok with heavy weights possible for flatter walks. Hills is what does me in as that is where the body mass and pack weight conspire. In the Tour de France the mountain climbers actually trade off muscle mass for weight saving as the extra muscle puts them at a disadvantage with the hills. The sprinters are a lot bigger and concentrate on muscle mass but then suffer in the Alps.

Hauling a 75 litre pack at 25 kilograms with a harness not designed for this is a totally painful and can convince you that the load is beyond you means but use say a One Planet Exact Fit Plus harness and while the load on the legs is the same the pain disappears along with the constant fidgeting trying to get comfortable. Just about any moderately reasonable harness can carry 15 kilograms but once past 18 kilograms harness design is critical for comfort.

The heaviest I have hauled was 38 kilograms on a flat route to the end of Hazard Beach and the great harness meant no great discomfort but boy any rise appeared to me like Everest so hearing people smaller than me hauling such weights over high passes amazes me. I did the same trip with another harness at 20 kilograms and it was just painful due to indifferent harness design.

Cheers Brett

PS I work on the principle of hauling the same load regardless of the trip length and just giving up on the things of comfort for longer walks like a proper frypan and real food

[Taurë-rana]

Hi Andrew,
This is a significant problem for me. I'm about 52kg sp 1/3 is a bit over 17kg, and also only 5' which makes a difference I think as well. Possibly the biggest weight saving is on food as I don't need as much to eat as bigger people often do, I have a women's sleeping mat, and a women's sleeping bag but the difference between what I can carry according to the formula compared to what a 90kg bloke can carry - 30kg, is in no way compensated for by smaller stuff. Obviously the tent (although I doubt many of the blokes here would be comfortable in my Vango), cooking gear, first aid gear, PLB, water, maps etc etc are still the same weight. There isn't much weight saved by having smaller clothes, sleeping bag and sleeping mat, and because I feel the cold I have to have plenty of warm stuff.

I was carrying about 16kg including 1.5l of water I think on my last 4 day walk which was fine, and I had everything I needed but it was the bare minimum. I'm going on a 7 day walk in a couple of weeks and am concerned about how to keep the weight down - the big problem is food on a longer walk. At least I can cut down on PLB and first aid gear as I'm going with a group.

When I did PB many years ago I literally couldn't carry my pack up the mountain and my friends had to take some of my stuff, much to their disgust. I can't remember how much it weighed. I don't think I was very fit though.

I've had to rebuild my gear collection so have been trying to keep everything lightweight - Aarn pack (helps to be able to carry more), WM sleeping bag, Thermarest Women's Pro 4 mat (or something like that), Vango Helium 100 tent, Kovea stove, and I'm going to get a WM or Montane down jacket. All not cheap but should last me a long time and keep me able to walk. I'm also investigating high energy bars to see if their energy to weight ratio is better than traditional foods.

I did try going for a short walk around the bush near home with a bit over 20kg a couple of years ago, and think if I'd spent any time with that weight my joints would have given up very quickly. Might be better now that I'm a bit fitter.

I'll be interested in the answers from other small people too.

[abowen]

Thanks Rachel,
I walk with many women who are amazingly strong for their size and I often wonder how they manage. Most have pack weights that are nearly the same as mine - 20 kilos.
There are others however, who can't get over the weight issue and in their minds the hurdle is too great. It would be nice to come up with some weight saving ideas so that they can get out and enjoy some longer walks. Some of the weight savers that I think have potential are sharing equipment - tent, cooking gear, PLB and first aid kits come to mind. Sharing food is also a possibility.
I have also considered whether there might be walk opportunities that use huts (although these cannot always be relied upon) and carrying a lighter weight emergency bivvy bag.
Better go. I have a walk planned for this weekend - rain or no rain - and need to get home and start packing.
Cheers
Andrew

[Taurë-rana]

Hope you have/had a good trip Andrew, it looks like the weather isn't going to be too bad now!

I can assure you my issue with weight isn't in my mind, but from experience. I also know women who can carry a lot of weight compared to their body mass, but I think it must just come down to exactly how you are built - I was talking to a friend today who had been in the army and said he carried a 75kg pack when he was 69kg and they were doing 9km/hour, but he also admitted that there aren't many people who can do that. And of course they were training for it every day.

[whiskeylover]

Pack weight is something I now focus on a lot more as I get older. 20 years ago, when I weighed around 53kg I was able to carry 26kg packs without too much difficulty. The main problem was getting the pack on - usually putting it up somewhere high to slip into the harness - or getting someone else to put it on for me.
I wouldn't have said I was strong, and I'm certainly not built like a pack horse (Height 5' 4"). Gear was heavier then, I only wore runners, and I was younger and fitter than my friends so tended to carry the heavy stuff but still have to walk slow for them. Someone once thought it was very funny to unbalance me on the beach and watch me trying to squirm out of my harness because I couldn't get back up with my pack on. Once I was up and walking with harness firmly done up, I didn't struggle too much as long as the track didn't have high steps (i.e. knee height) or scrambling bits. A bit slower up hills, but still faster than some.

Now I weigh 57kg and try to keep my pack weight below 18kg. Ideally I should aim for around 14kg, but I am happy to trade weight for comfort a little (including medicinal liquids of course). Hubby tries hard to carry the heavy stuff and gets me to carry the gourmet food so my pack weight reduces as the days go by. He is also only small, although of course much stronger, but we manage to keep his pack weight around 22kg usually.

Personally I feel that a good harness system and physical fitness are the elements that contribute to enjoyment of walking with a pack on - and if I start to think my pack is heavy I just imagine how comfortable my camp is going to be, and how fantastic the meal will be, because I was willing to carry more weight. The other thing that helps me now is two Leki poles that distribute the weight more evenly.

Sharing the load is of course the answer - find a young fit male - preferably related to you and make him carry the extras and run on ahead to set up camp. Tell him it is just because he is so strong and fit that you need to slow him down a bit. Or alternatively let him think his pack weighs the same as yours and he just needs to carry the tent and stove to share the load - Note: Never let him pick up your pack if this is your strategy.

[Nuts]

I think your friend is stretching the truth there a bit Rachel... Ive heard that before, 40-50kg possibly... on occasion. We did some training with/providing medical assistance for the SAS in Perth and even their packs werent that heavy (worn out knees are what has ended many of their careers)

I would say that (especially) smaller people should carry the least they can... dont stop at 1/4 if 1/5th is possible. There are all sorts of ways to achieve this, many already mentioned on this site.

IMO Harness doesnt matter a hoot unless your (possibly happily) overloaded. Just look at the ultralight packs (without any real 'harness') and the range of people who carry them without drama. Look at how some of the larger manufacturers add padding as the intended load increases... its needed. Perhaps a good place to start is with a pack intended for the weight 'one' wishes to carry, rather than something to heavy and large (or even something to small (and kid yourself that it should feel comfortable with more... or even blame the manufacturer ))

[whiskeylover]

You're probably right about the harness issue Nuts "if" one is able to reduce ones needs/wants on a walk. I have considered getting a lighter pack as I have an old Macpac Cascade, but the trouble with them is they never die, so I find it hard to justify buying another pack when the one I have is good for the job.

[Nuts]

Hi (mrs?) whiskeylover, I was typing while you were, was more comments for the above, but yeah money and loyalty come into it. I have a WE Expedition pack that I cant part with (but never use). I'm a bit hesitant about recommending anyone starting there (you would need the experience and the other gear to be around 8-10kg) but golite pinnacle packs are on sale from around the $100 mark atm.....

[corvus]

Hope you have/had a good trip Andrew, it looks like the weather isn't going to be too bad now!

I can assure you my issue with weight isn't in my mind, but from experience. I also know women who can carry a lot of weight compared to their body mass, but I think it must just come down to exactly how you are built - I was talking to a friend today who had been in the army and said he carried a 75kg pack when he was 69kg and they were doing 9km/hour, but he also admitted that there aren't many people who can do that. And of course they were training for it every day.

T-r ,
75kg pack 9 kph and weighing 69kg (my weight) come on your friend must be taking the proverbial not even in the extreme would the Services allow such a breach of OHS standards have you ever tried to lift let alone carry more than your body weight for more than a few paces.
corvus

written b4 dinner ,posted after so missed the other posts

[corvus]

Proper weights for the Military,
Yomp is Royal Marines slang describing a long distance march carrying full kit.
The most famous yomp of recent times was during the 1982 Falklands War. After disembarking from ships at San Carlos on East Falkland, on 21 May 1982, Royal Marines and members of the Parachute Regiment yomped (and tabbed) with their equipment across the islands, covering 56 miles (90 km)[1] in three days carrying 80 pounds (36 kg)[2] loads.
corvus

[Taurë-rana]

I don't know corvus, I'll ask him again. Maybe it was just a one off. I know he was very fit - he was the PT instructor and ran marathons as well.

whiskeylover, I used to carry a pack I couldn't put on as well, so it must have been heavier than what I try to carry now. Having just lifted 450kg of boxes weighing 25 - 30 odd kg each into the car, then back out and carrying them into the workshop, I think it's possible I can carry a bit more than 16kg at the moment. (Pity the bench they were sitting on couldn't take the weight, it collapsed and I now have well over 500kg of boxes all over the floor and a bruised foot!) More pack carrying preparation tomorrow when I clear it up

Sharing the load is of course the answer - find a young fit male - preferably related to you and make him carry the extras and run on ahead to set up camp.

I have tried, I have two strong, fit, capable sons who are not interested in bushwalking So then I suppose we could get back to one of the other topics being discussed at the moment...

[north-north-west]

Not owning a pair of scales or being overly worried about my own weight, I can't be exact with this sort of thing. I pack what I think I'll need or don't feel comfortable leaving behind. A little extra food always, plus often plenty of water - there's not a lot of reliable water around on the ridgetop walks in the Alps during the summer. Sometimes it's a struggle but I just keep plodding on. Slow as a geriatric slug uphill, but I walk for as long as I feel like it - which can be as much as 14 hours in summer - so I can cover a fair bit of distance in a day.

I suppose it's mental more than anything. It hurts sometimes, but it's still better than not being there, so I don't obsess over weight. But I'd be surprised if my usual weekend load - including food and water - came in at under 20kg. And I'm 52, 5'3" and weigh somewhere around 8 1/2 stone. *shrug*

[daznkez]

Hi,
I'm 5ft and 48kg i regularly carry a pack weight of between 12-14kgs for 3-5 days walk my partners pack is only 1 to 3kgs more than mine. Last year we rock climbed up the west face of mt geryon which required us to carry 20(mine) and 27(Daz's)kilo packs, which was all the usual gear plus 1week of food and a full climbing rack and ropes. As per corvus's post we find it hard to believe that anyone could carry twice this weight and look at anything but the ground when walking. Furthermore, walking down off a range in tassie (eg alpha moraine) is likely an accident waiting to happen, for their walking partners to deal with. Some of the things I do to save weight are,carry a 3/4 length exped down mat (this is a great space saver over a thermarest). i have a woman's XS down sleeping bag with polar fleece inner for extra warmth.You can also slip your mat inside it in summer. My summer gear is pretty much the same as my winter gear as i have been caught out trying to save weight in summer in tassie and regreting it. I feel the cold hence i take a lot of extra clothes,this is where most of my wight lies. I own a lot of icebreaker stuff which has good layers at different weights. I only have one stuff sack for all my gear except food. I was thinking of getting a aarn pack but am unsure how it will stand up in the tassie scrub (i currently have a canvas pack with pack cover).
Hope this helps happy walking

[under10kg]

I think with modern, lightweith gear, pack weight is much less than the old days.
For example, I am not an extreme light weight guy as I value comfort at night etc, but my recient 10 day walk in Tasi I had a pack weight of 12 kg and I did not share anything. WIth a full harness pack like the comfortable Aarn pack, this would have been under 14KG

[Drifting]

formulas are silly. According to that, I should carry 41 kgs. No thank you.

[flyfisher]

I'd have to agree with that Drifting, that would be an awfull lot of clobber , nobody could need that much, most probably don't own that much

(except for a Scottish Collingwood supporter)

ff

[Ent]

I have to disagree big time with the comment that pack harness does not matter. Having spent nine months dodging back surgery I became rather well advised by the orthopaedic surgeons on how important it is to look after your back. I have had both knees done and frankly that was a walk in the park compared to back issues. Going light weight is ok but compromising the harness is asking for a lot of pain and suffering with an uncertain treatment regime as the success rate for back surgery is poor while knees it is excellent. Disc failure is very common in people over thirty and if it ruptures inward you do not know about it but if it goes backwards towards the spinal column then you will know about it.

The old worn out knees issue was also debunked by the orthopaedic surgeon as well. Apart from accident damage the time clock is set by your parents with weight carried moving it in a few years at most. Also if you can put up with many years of discomfort the knee joint will often self clear as the jamming bits get ground down. Unless you are ultra careful most people are at least 10 to 20 kilograms over fighting weight so if you are using the "worn" out approach then give up all non essential food and booze and get down to the idea weight as the amount of time a pack is on your back is minimal compared to carrying it in-built weight.

I actually took up walking again after all the medical issues appeared as walking was quoted as the best form of exercise by the medical people providing that I got the harness right. The back damaged was done before hand by years hunch over too low desks in too low chairs rather than hauling any weight around. The knees were just a fact of genetics. I think it quackery of the tenth order to advise anyone that a pack harness does not matter and blaming pack loading for normal wear and tear injuries. I suppose everyone needs an excuse

As for the alleged weight carried by our military friends I to was quoted a ridiculous weight combined with a times and distance that exceeded any measure of reality and like Corvus a bit of reading revealed that the military have load carrying sussed but it appears that a lot of grunts that do not make it into the more elite units have a dubious grasp of reality with this and a lot of other claims

As for formulas they are a useful guide rather than an absolute truth as strength as a ratio to mass decreases. By that, an elephant could not do chin ups while a cat can jump many times it height but normally chooses not to Bit like pack weight, just because you can does not mean you should if you can find alternative methods of getting the level of comfort you seek when camped then go for it.

Cheers Brett

[flyfisher]

A lot of good common in that post Brett. You and I should have a weight reduction excercise to help us lose a bit.About 15kg would b good for me, then it would be like walking without pack weight.
Regarding harness, I bought a new pack around 18 months ago and it is way more comfortale than the one it replaced, and doesn't worry my back at all.

ff

[Nuts]

I have to disagree big time with the comment that pack harness does not matter.

Who said pack harnesses dont matter?

Having spent nine months dodging back surgery I became rather well advised by the orthopaedic surgeons on how important it is to look after your back.

With correct lifting I would suggest carrying the pack has very little chance of Causing spinal problems... Your back should be held in correct alignment (properly fitted) and warm! What I Was saying (or at least (obviously?) meaning) is that (assuming it has an adjustable waist belt, shoulder straps and to a lesser extent chest strap) the padding, model (design) etc matter less (and less) as the weight you are carrying reduces....

I have had both knees done and frankly that was a walk in the park compared to back issues. Going light weight is ok but compromising the harness is asking for a lot of pain and suffering with an uncertain treatment regime as the success rate for back surgery is poor while knees it is excellent.

There are several ways to wear out your knees, Patella Chondromalacia (downhill, excessive weight, muscle imbalances.........) and the effect, whilst operable, has little chance of not reoccurring. The operation (in my case, smoothing of the roughness on the end of the femur) is an attempt to reduce pain, it is expected that the offending activity needs to cease. (Ask your surgeon, iv'e seen several (likely all of them) in Tassie


Disc failure is very common in people over thirty and if it ruptures inward you do not know about it but if it goes backwards towards the spinal column then you will know about it.


The old worn out knees issue was also debunked by the orthopaedic surgeon as well. Apart from accident damage the time clock is set by your parents with weight carried moving it in a few years at most.


I know some (former) guides that would suggest this is rubbish.... (cringe)....their parents never had knee problems in their twenties.....

My parents have/had no issues into their seventies

Also if you can put up with many years of discomfort the knee joint will often self clear as the..........

Cheers Brett

[pinarello]

I agree with scavenger in thinking it is basically a mental or psychological thing. women get told their whole life that they cannot carry this, that they need help when lifting that. Parents, brothers, friends mean surely well when carrying stuff for them while at the same time undermining womens self-confidence that they do have the ability to carry things that are, well heavy. nobody ever tells them that they can actually carry a load of lets say 15kg. guys on the other hand are always to be assumed the ones who will be just fine no matter what comes along their path (in terms of lifting that is). as a result they approach the task with a positive mindset and just assume they will be able to do it; i think they are also a lot more pressured into not showing any signs of weakness. it's hard to find guys who are actually comfortable in admitting that this specific load is too heavy and they cannot cope.

i know i am generalising and not every individual fits the categories but we are all surrounded and influenced by a society and culture that has developed in certain ways and that treats man and women differently. of course we rise above those cultural determinations but at the same time they are part of our social fabric.

as for me personally, i weigh around 55kg at 172cm (5'7" in old money, i think) and i try to carry as less as possible like everybody else, but it's rather a question of how annoying it is gonna be than thinking it might get too heavy and therefore i cannot do this. i tend to carry around 15kg. (i think, have no scales....)

[under10kg]

I do find a pack without a frame very comfortable up to about 6KG. I do have to watch my lower back too.
For those with more back issues I feel the Aarn pack could be a big help. These packs have several features not available in any other pack designs. One of these ideas is to transfer some of the pack weight to the front pockets. The idea is to have some weight in the balance front pockets that transfer the weight to the hip belt, so the weight from the front or your body to the back is neutral. So no more walking with a slight front lean and this reduces a lot of stress on your back.

[Ent]

A lot of good common in that post Brett. You and I should have a weight reduction excercise to help us lose a bit.About 15kg would b good for me, then it would be like walking without pack weight.
Regarding harness, I bought a new pack around 18 months ago and it is way more comfortale than the one it replaced, and doesn't worry my back at all.

ff

Yes I long to get back to 90 kilograms that I oh so briefly touch down to an increasing number of years back. Though frequently discussed and debunked is standard weight to height tables and on them my idea body mass is allegedly 83 kilograms but that appears rather on the light side given my frame but does sort of suggest maybe any ratio should apply to that weight rather than my current weight. Given the 1/3 maximum guide, I prefer 1/4 of body mass, it does make you wonder over the 105 litre packs that get sold. I suppose the long suffering family mules just have to lug it or stay at home but 30 kilograms is a decent weight especially up hill.

Back on packs it is interesting that a leading Australian pack company One Planet has like a few other manufacturer multiple back lengths. What is not as well known is the have multiple strap lengths to cater for the outliers with apparently the female form being the most challenging to get the right combination. Worthwhile bearing in mind that a more comfortable setup could be possible for One Planet owners. Apparently the sternum strap height adjustment range was restricted by OP in the hope that people will drop to the need to look at a different length straps or revisit if they have the correct back length set.

One thing that does get missed is training for the task at hand. As they say the best training is doing in training what you will be doing in the real world. We spend most our lives not carrying weight and then might do a few day walks or overnight walks in preparation for a long walk. Many carry less weight on the shorter walks so it is not surprising that on longer walks people breakdown or generally get rather worn down by carrying weights they have not trained for. The joy of youth is you can get fit while doing this but I am finding with age injury is more likely so like the idea of a fixed weight for all overnight walks and work on the principle of lightening the items thus reducing the comfort for longer walks. The problem is there comes a point where the base load can not be lighten any more (without significant cost or comfort trade-offs or obtaining more knowledge) so that becomes the walk length limit. At least technology is coming to the rescue along with multiple sizing options so a 5" 1' women is not forced to carry a sleeping bag suitable for a 6' male as was common thirty years ago. The last bastion of one size fits all is tents but maybe we will have multiple sizings as I think the current approach of claiming a weight victory due to a smaller tent rather hollow. Hands up those that carry, or are planning to carry, a tent with one person more rating than what will normally sleep in it.

Cheers Brett

[corvus]

I am looking at a Scarp 2 to replace my Microlite just to give me that bit of extra space ,Microlite is a perfectly good Tent just does not suit my needs.
corvus

[ninjapuppet]

For those with more back issues I feel the Aarn pack could be a big help. These packs have several features not available in any other pack designs. One of these ideas is to transfer some of the pack weight to the front pockets.

Im a chiropractor, and currently using the one planet McMillan which i'd say is the best out of my previous 5 packs. Its the one i recommend to my patients not because my association's endorsement, but because I feel its got one of the best harnesses that keeps the spine in neutral throughout the gait phase. Now that you mention these Aarn packs, i might look at getting one soon and trying it out. if its as good as you say, I'd also be getting my Chiropractic association to do a peer review on the product too. are there any models which you recommend?


back in my army days, i was 62kg. On an average "hump" (pack march) my pack was about 30kg, loaded webbing was 12kg, and my loaded rifle was 5kg so carrying 50kg wouldnt be a stretch. I wasnt infantry but my Sergeant was, and was constantly reminding us how soft we were compared to infantry guys.
maybe it was only to motivate us, but i was glad we didnt have any claymore mines or heavy calibre ammo to carry!

I was just watching a TV series: everest, beyond limit season 3, and it said that sherpas often carried more weight than their own bodyweight! and not on flat ground either!
heres some more info: http://www.timesonline.co.uk/tol/news/w ... 534256.ece

tho, i wouldnt recommend as a chiropractor!

[Taurë-rana]

Taken from a paper about Australia’s Soldier Modernisation Program:

34. A previous Australian study on load carriage [5] identified a range of load
configurations, three of which have been identified as important to the Soldier
Combat System. These are given in Table 1.
Configuration Target Weight (kg) Comments

Load Configuration 1
(LC 1)
35kg Similar to existing Patrol Order, but more
task oriented. Represents load carried for
short duration patrols (ie less than 3 hours)

Load Configuration 2
(LC 2)
35kg Similar to existing Patrol Order. LC 2
represents the load carried for longer
duration patrols of up to 12 hours duration.
Load Configuration 3

(LC 3)
50kg Commonly referred to as Marching Order.
The load includes items for subsistence in
the field for three days with water and
ammunition resupply.

35. Whilst the target weight is defined for individuals it has been identified that
each soldier does not carry the same equipment. In fact, given current equipment
within the section, there is almost a 10 kg difference between the heaviest (machine
gunner carrying 36 kg) and lightest load (scout carrying 27 kg) for LC 1. The target
weights identified will be used as the maximum to be carried by any individual soldier
in a particular configuration of the WUNDURRA Soldier Combat System.

36. Current LC 3 loads are on average 10 kg lighter than the target weight given in
Table 1 with the heaviest load being around 42 kg. This would indicate some room for
expansion. It should be noted however that the distribution of loads in LC 3 should be
such that the majority of extra weight can be dropped if required for activities such as
an assault. In other words a quick transition from LC 3 to LC 1 or LC 2 is desirable.
Note, however, that all of these weights are above the often-stated 1/3 body weight as
a maximal long-term load carriage weight.

Sorry it's not very easy to read, just thought it was interesting. Looked at a couple of threads on forums too, one comment was that 30-40kg would be comfortable for people to carry! As Brett pointed out, we don't train for carrying heavy loads for a long period of time so are not accustomed to it. Be interesting to see whether if we trained every day with heavy packs how much easier it would be to carry them on our walks. It's quite amazing the difference just on a day walk between being used to walking a reasonable distance and not. Perhaps I should try walking with a weighted pack for the next fortnight and see if it makes my next multi-day walk easier. Hopefully it won't just make my joints all go on strike

Aarn packs - they are definitely more comfortable with the weight distribution. Just a bit fiddly to get right.

[under10kg]

Now that you mention these Aarn packs, i might look at getting one soon and trying it out. if its as good as you say, I'd also be getting my Chiropractic association to do a peer review on the product too. are there any models which you recommend?

There is a big range of aarn packs and it depends on how much volume you want the pack to be.

I suggest you give Aarn a ring in Christchurch. His number is on the contact link at his site. His packs have been subject to some scientific research comparing energy used compared to the normal type of pack.

http://www.aarnpacks.com/

[Tony]

I have been away and came back to this great thread.

I have recently been doing some research into backpacks or as the scientific circles call it "Load Carriage" with the idea of putting my findings together to start a similar discussion on bushwalk.com. but due to recent work pressures this will take some time to put it all together.

There have been many very good comments so far and here are some of my findings.

From what I have read so far 30% of body weight maybe an ideal maximum backpack load weight but as usual things are not that simple. Several reviews of load carriage have concluded that possible determinants of load carriage ability include age, anthropometry, strength, training, body composition and gender (Hainsamn 1988, Knapik et al. 1996). Other relevant factors, climate, terrain and gradient. (Attwells et al. 2006).

Another factor that I have been reading about is perceptual responses (eg perceived stress, perceived strain, perceived exertion etc), some think that this maybe more important than what people are actual doing.

A lot of the literature on load carriage is by the US military as the level of sophistication and protection goes up they require their soldiers to carry more and more gear. in the US Desert Storm soldiers carried 45+ kg and I have read about some US army marches where the soldiers have to carry 76kg.

As for AARN style of packs (or Double packs as they are called in the research papers), the military have done a lot of research into them and as it has been suggested, they are the most energy efficient way of load carriage this is because the most efficient way of load carriage is to keep the load on your center of gravity and at least on flat terrain the double pack does this very well but according to the literature the double packs are not with out problems, (I have not used an AARN pack or even seen one, this information is from scientific research articles) in the reports that I have read about double packs some subjects report over heating, restricted breathing and in rugged terrain, view obstruction, however one study reported that "there was an percentage increase in march time when using the double pack, whatever the load" Thus 6% (light load); 14% (medium load) 28% (heavy load) (Charteris 2000).

Tony

[under10kg]

(I have not used an AARN pack or even seen one, this information is from scientific research articles) in the reports that I have read about double packs some subjects report over heating, restricted breathing and in rugged terrain, view obstruction, however one study reported that "there was an percentage increase in march time when using the double pack, whatever the load

In my experince of using several Aarn pack models in Australia and New Zealand, the front balance pockets of Aarn packs do not overheat the body due to the internal frame system design. This holds the balance pockets away from the body and allows full air flow. These can be customised for woman with large busts.

When scrampling, one can undo an attachment to the balance pockets and move them out of the way for hard scrambling. This allows a full view of ones feet etc. Personally, I like the even front/back balance weight distribution when scrambling as you feel so much more balanced.

You need try an aarn pack to see how it makes load carring much more easy. They are a bit more of a fiddle to put on.