What difference does it make?

[Marta]

Like that old joke...Which weighs more--a pound of feathers, or a pound of bricks?

What is that pound made of? Is it water in the desert? Is is stove fuel in the snow? Or is it a leather belt with a fancy buckle?

There's a rule of thumb that every extra pound slows a person down two seconds per mile.
http://www.letsrun.com/forum/flat_re...thread=1771473
I think that gets much worse than 2 seconds/mile as you get further away from ideal body and pack weight. I've known a few hikers packing a hundred extra pounds of body weight and substantial packs who usually hike four or five miles in a day. It's not so much the per-mile speed that hurts them as the moving parts threatening to break down that makes them need to stop, rest, and repair before continuing.

What's a pound? Turn steeply uphill, and every extra pound, of pack or body weight, hurts.

I look at pack weight as a percentage of body weight. A 15# pack is not much for a 200-pound person. For a 40-pound child, however, it's huge.

My husband and I have played with pack weight the way horses are handicapped. When we backpack together, we trade gear between us to even out our hiking paces. In general, he's got a better weight-to-strength ratio so he can carry more weight and we'll hike about the same speed. But if he didn't sleep well, or for some other reason doesn't feel great, and I do, I'll take some of the gear he usually carries, and our hiking speeds will equalize again.

A more extreme example was when I hiked several hundred miles with a young man half my age. We hiked about the same speed. He was carrying a 65-pound pack and I was carrying around 20-25 pounds.

Beyond having fun handicapping hikers, you just have to decide what your goals are. Even if I carried nothing at all, I still wouldn't be challenging Jen or Scott or Karl for the supported record. ;-)

[pickNgrin]

Obviously, since you have to carry that extra pound, you have to expend energy to do it. You have to lift it up slightly on every step, and you have to carry it up and over every mountain.

As an example, compare an 18lb pack to a 17lb pack. If it takes a certain amount of energy to carry the 17 lb pack, then it will take 18/17 as much energy to carry the 18lb pack. That is about 6% more energy. This is admittedly a simplistic analysis, but it gives a decent estimate of the difference.

If you could walk 20 miles in a certain day with the 17lb pack, then you could reasonably expect to only make it 18.8 miles with the 18lb pack (expending the same amount of energy). Over the course of five days, you would cover 100 miles with the 17lb pack, but only 94 miles with the 18lb pack.

Is that an appreciable difference? It is up to you to decide. You could do the same type of calculation with a different starting pack weight if you want.

[Uriah]

Obviously, since you have to carry that extra pound, you have to expend energy to do it. You have to lift it up slightly on every step, and you have to carry it up and over every mountain.

As an example, compare an 18lb pack to a 17lb pack. If it takes a certain amount of energy to carry the 17 lb pack, then it will take 18/17 as much energy to carry the 18lb pack. That is about 6% more energy. This is admittedly a simplistic analysis, but it gives a decent estimate of the difference.

If you could walk 20 miles in a certain day with the 17lb pack, then you could reasonably expect to only make it 18.8 miles with the 18lb pack (expending the same amount of energy). Over the course of five days, you would cover 100 miles with the 17lb pack, but only 94 miles with the 18lb pack.

Is that an appreciable difference? It is up to you to decide. You could do the same type of calculation with a different starting pack weight if you want.

This is a simple analysis for sure, but/and a relatively good one. (Carrying) extra mass certainly equates to extra energy output being required (even downhill). But it doesn't quite convert mathematically to distance covered that readily or easily, and that's where things get messy. Individual variances have a larger effect.

For some (typically ectomorphs), carrying any extra mass is an exponentially more difficult task as the time doing so and incurred fatigue accrues. For others (e.g., mesomorphs/endomorphs), the added weight is merely a nuisance. As super moderator Marta mentions, a more optimal equation is perhaps to figure it all out as a percent of body weight added by way of the backpacking gear. (It would elicit a more accurate indication of effect.) A 200-lb dude carrying 20-lbs expends (relatively) less than a 100-lb woman doing so, all other variables comparable.

There's no easy way to to study something as complicated as backpacking long distances over varied terrain while encountering varied climatic and nutritional conditions. But your explanation is pretty much spot on in that it simply takes more work to carry more weight, regardless of amount.

[One Half]

Obviously, since you have to carry that extra pound, you have to expend energy to do it. You have to lift it up slightly on every step, and you have to carry it up and over every mountain.

As an example, compare an 18lb pack to a 17lb pack. If it takes a certain amount of energy to carry the 17 lb pack, then it will take 18/17 as much energy to carry the 18lb pack. That is about 6% more energy. This is admittedly a simplistic analysis, but it gives a decent estimate of the difference.

If you could walk 20 miles in a certain day with the 17lb pack, then you could reasonably expect to only make it 18.8 miles with the 18lb pack (expending the same amount of energy). Over the course of five days, you would cover 100 miles with the 17lb pack, but only 94 miles with the 18lb pack.

Is that an appreciable difference? It is up to you to decide. You could do the same type of calculation with a different starting pack weight if you want.

I like this analysis, as simple as it is, works very well.

[Slo-go'en]

At 20 pounds, 1 pound represent 5% of the weight, while at 10 pounds, it represents 10% of the weight. So that 1 pound has a larger impact when the initial weight is low than when it's high. Of course, it's a lot easier to loose 1 pound out of 20 then it is to loose 1 pound out of 10.

[SkeeterPee]

In marathon running I have read, it averages about 1-2 seconds per pound per mile. so if you loose 10 lbs, you pace / mile goes down 10-20 seconds per mile or 260 to 520 seconds over the marathon. Not sure if there would be a different effect on hiking as weight makes more difference on hills vs flat.

[rocketsocks]

Like many I can feel a pound or two, but it certainly isn't breakin' me down, even 10lbs. isn't a big deal...much ado about nuthin'

[Lnj]

Speaking from the school of one who needs to lose body weight more than pack weight, but pack weight as well.... At the end of the day it comes back down to... Is it worth it? To you, and FOR you, no matter the weight and the work involved to carry it, or how long it takes you to get where you are going... if you can honestly and truthfully answer that it is worth every grunt and groan and you enjoy your hike immensely, then no further calculation or adjustment is required. If your weight or your pack weight or your travel time is steeling away some of your hiking joy, then find the culprit and adjust accordingly.

[poolskaterx]

1.5 lbs makes a HUGE difference!
You should see the smiles on my 2 buddies faces when at the end of the first day hiking I pull out the 3 beers that have been stowed away in my pack.
I have a weight that is comfortable for me and works well for my pack; I add or take away comforts for necessity. I am a gram weenie however I like getting my load light so I can add in comforts. Fully loaded for 3-4 days in the winter I will not go over 28lbs but in the summer I may still be at 27-28 just because it makes my experience more enjoyable.

[Malto]

A pound here and a pound there and pretty soon it ends up being real weight. One pound won't make much difference, but generally most hikers could shed much more than a pound.

[rafe]

One pound, not much difference. Five pounds or more, very noticeable, from the moment you put it on.

Forty years ago my hiking pals and I were beasts of burden lumbering through the White Mountains. We hardly ever walked more than eight or ten miles a day. Nowadays I carry half that load.

[-Rush-]

Regardless if you're into the UL thing or not.. I can't think of a time when carrying an extra pound for the hell of it made a lot of sense. The less weight = the less stress on your body with every step you take. All of that stress adds up over a long hike. I don't think it matters as much for short trips or those with little elevation change. If you need to carry an extra pound of gear to suit the hike - or for me an extra 7lbs of water - you do what you gotta do, but only if necessary. I find I hike farther, faster, and feel less destroyed at the end of a long day when I'm carrying 20lbs vs 30lbs.

[Maydog]

Wouldn't you want to add body weight to the equation? I say 'yes'. It still takes energy to move even without a pack. If a person weighs 150 lbs, and puts on a 15 lb pack, then they increased their total weight by 10%. If they increase their pack weight to 20 lbs, then they added 33% more pack weight but only 3% more total weight vs. the 15 lb pack.

Obviously, since you have to carry that extra pound, you have to expend energy to do it. You have to lift it up slightly on every step, and you have to carry it up and over every mountain.

As an example, compare an 18lb pack to a 17lb pack. If it takes a certain amount of energy to carry the 17 lb pack, then it will take 18/17 as much energy to carry the 18lb pack. That is about 6% more energy. This is admittedly a simplistic analysis, but it gives a decent estimate of the difference.

If you could walk 20 miles in a certain day with the 17lb pack, then you could reasonably expect to only make it 18.8 miles with the 18lb pack (expending the same amount of energy). Over the course of five days, you would cover 100 miles with the 17lb pack, but only 94 miles with the 18lb pack.

Is that an appreciable difference? It is up to you to decide. You could do the same type of calculation with a different starting pack weight if you want.

[Deacon]

Every little item doesn't weigh much by itself, but it sure does add up when you throw it in the pack. Heck, just carrying that extra set of keys in my pocket all day gets to be very noticeable.

[Engine]

A pound here and a pound there and pretty soon it ends up being real weight. One pound won't make much difference, but generally most hikers could shed much more than a pound.

I'm all for getting fit and losing extra body-fat, but 1 pound of fat rides completely different than 1 pound hanging off your back. Weight around my core is MUCH less noticeable than it is pulling against me. It's similar to the old adage about a pound on your feet equaling 5-6 pounds on your shoulders. As for comfort (and maybe some efficiency) a pound on your shoulders is probably equal to some undefined larger amount on your person. Many of us (me included) could stand to lose some weight, but 1 pound of fat doesn't equal 1 pound when it comes to taking it off your back. 1 needed pound by itself isn't a huge deal either way, but over the length of a long hike, I want to lighten the load as much as I reasonably can.

Every little item doesn't weigh much by itself, but it sure does add up when you throw it in the pack. Heck, just carrying that extra set of keys in my pocket all day gets to be very noticeable.

Where you put those items makes a real difference as well. Yesterday I was tweaking how I load my pack and when I had my tent (36 ounces) in the front mesh pocket, it caused the pack to pull away from my shoulders. I moved it to a side pocket and presto, completely different feeling with a pack that rode the way it should. On top of that, it'll now balance the weight from a full platypus on the other side. :-)

[rocketsocks]

I'm all for getting fit and losing extra body-fat, but 1 pound of fat rides completely differently that 1 pound hanging off your back. Weight around my core is MUCH less noticeable than it is pulling against me. It's similar to the old adage about a pound on your feet equaling 5-6 pounds on your shoulders. As for comfort (and maybe some efficiency) a pound on your shoulders is probably equal to some undefined larger amount on your person. Many of us (me included) could stand to lose some weight, but 1 pound of fat doesn't equal 1 pound when it comes to taking it off your back. 1 needed pound by itself isn't a huge deal either way, but over the length of a long hike, I want to lighten the load as much as I reasonably can.



Where you put those items makes a real difference as well. Yesterday I was tweaking how I load my pack and when I had my tent (36 ounces) in the front mesh pocket, it caused the pack to pull away from my shoulders. I moved it to a side pocket and presto, completely different feeling with a pack that rode the way it should. On top of that, it'll now balance the weight from a full platypus on the other side. :-)

agree...it's a failed theorem of the "look at me" group.

[AfterParty]

If you can honestly tell the difference in 1 lb your pack suspension doesn't work very good or you have maxed out the pack suspension. Have some one put a 1 lb weight in your pack randomly and shoulder it 10 times at random and see how many times you get it right.

[QiWiz]

My experience is that I can feel the difference when a pound is gone, based on eating 1 to 1.5 pounds of food a day and noticing how the pack feels lighter every day on a multi-day trip. The lighter my pack, the more I enjoy carrying it.

[Feral Bill]

1 pound over a day with 2500 feet of climbing = 2500 foot-pounds at 10% efficiency in using food energy = 8 Calories = 1/29th of a Snickers.

[rocketsocks]

1 pound over a day with 2500 feet of climbing = 2500 foot-pounds at 10% efficiency in using food energy = 8 Calories = 1/29th of a Snickers.

i can burn more calories droppin' the kids at the pool.