# I hold 100lb in the air for 10 mins - Do I burn any calories/do work ? **URL:** \ **Category:** Factual Questions\ **Created:** [August 13, 2014, 3:13pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442 "2014-08-13T15:13:24Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [August 13, 2014, 3:13pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/1 "2014-08-13T15:13:24Z")
I get the physics behind - if you lift and hold a mass stationary, then no work is being done on the object. (for the time that it is held) However, is it true that the body is not doing any work internally i.e. does the heart need to do more work since the blood vessels are more constricted ? does the heart need to pump more blood to the muscles ? Why do weight lifters sweat a bunch and breathe faster when holding a weight stationary above their head ? My understanding is that the body is actually doing a lot of work supplying energy to the muscles holding - that work is not conserved but converted to heat. Is this wrong ? This is inspired by this thread - [Question about a vacuum - Factual Questions - Straight Dope Message Board](http://boards.straightdope.com/sdmb/showthread.php?t=730869) ---
**Author:** ![DrCube](https://avatars.discourse-cdn.com/v4/letter/d/a3d4f5/32.png) [@DrCube](https://boards.straightdope.com/u/DrCube)\ **Post date:** [August 13, 2014, 4:16pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/2 "2014-08-13T16:16:49Z")
Well, you’re not doing work (in the strict physics sense), but you’re using energy and hence burning calories. It takes the force of your muscles to counteract the force of gravity on the weight, or else it would fall. ---
**Author:** ![DrCube](https://avatars.discourse-cdn.com/v4/letter/d/a3d4f5/32.png) [@DrCube](https://boards.straightdope.com/u/DrCube)\ **Post date:** [August 13, 2014, 4:18pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/3 "2014-08-13T16:18:45Z")
> **[Isometric exercise](https://en.wikipedia.org/wiki/Isometric_exercise)** > > An isometric exercise is a form of exercise involving the static contraction of a muscle without any visible movement in the angle of the joint. The term "isometric" combines the Greek words isos (equal) and -metria (measuring), meaning that in these exercises the length of the muscle and the angle of the joint do not change, though contraction strength may be varied. This is in contrast to isotonic contractions, in which the contraction strength does not change, though the muscle length and j Th... ---
**Author:** ![lazybratsche](https://avatars.discourse-cdn.com/v4/letter/l/ba8739/32.png) [@lazybratsche](https://boards.straightdope.com/u/lazybratsche)\ **Post date:** [August 13, 2014, 4:26pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/4 "2014-08-13T16:26:51Z")
On a microscopic scale, you’re doing plenty of work. When you apply a force with your muscle at a constant position, the myosin in your muscle cells is continually grabbing onto actin filaments, pulling, letting go, and then slipping back. The myosin “power stroke” is applying force over distance, i.e. work. With sensitive enough equipment you can actually [measure the work done by a single myosin protein](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3487478/?report=reader). ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 13, 2014, 6:55pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/5 "2014-08-13T18:55:24Z")
> [@](#): > > Quoth **DrCube** : > > Well, you’re not doing work (in the strict physics sense), but you’re using energy and hence burning calories. It takes the force of your muscles to counteract the force of gravity on the weight, or else it would fall. Both of these sentences are true, but they are completely unrelated to each other. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [August 13, 2014, 7:09pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/6 "2014-08-13T19:09:00Z")
A hovering helicopter or a rocket hovering on a flaming jet certainly is not using zero energy. It’s just being converted into heat and air currents rather than adding to the (gravitational) potential energy of the device. A weight dragged horizontally against a frictional resistance should be using energy, even though the potential energy of the weight is not increased. ---
**Author:** ![DrCube](https://avatars.discourse-cdn.com/v4/letter/d/a3d4f5/32.png) [@DrCube](https://boards.straightdope.com/u/DrCube)\ **Post date:** [August 13, 2014, 7:10pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/7 "2014-08-13T19:10:45Z")
> [@Chronos](#): > > Both of these sentences are true, but they are completely unrelated to each other. I’m not sure what you mean by that. I wasn’t clear, I suppose, that if a _table_ is holding up the weight, or some other rigid object, it neither does work nor uses energy. Simply counteracting an external force doesn’t _necessarily_ require an energy expenditure. But because of the way the human body is built – to be flexible along certain joints and therefore require muscular contraction to stiffen the body against a load – people do burn calories (i.e., use energy) while supporting a weight, even if they’re performing no work on the load. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [August 14, 2014, 1:21am UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/8 "2014-08-14T01:21:44Z")
> [@lazybratsche](#): > > On a microscopic scale, you’re doing plenty of work. When you apply a force with your muscle at a constant position, the myosin in your muscle cells is continually grabbing onto actin filaments, pulling, letting go, and then slipping back. The myosin “power stroke” is applying force over distance, i.e. work. With sensitive enough equipment you can actually [measure the work done by a single myosin protein](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3487478/?report=reader). Exactly which why the statement that no physics work is being done is _false_. Various motor units are taking turns contracting, exerting a force over a unit distance, then relaxing and repeating. There is no _external_ physics work being done upon the object but there is plenty of _internal_ physics work being. Calculating that amount of work is however a much complicated task than the issue of calculating external physics work. (How many times is each motor unit firing? How far is each contracting each time? With how much force? Varies with every motor unit involved and during the course of the task as some motor units fatigue and others are recruited.) But measuring the calories needed to keep it aloft compared to be at rest is likely a good ballpark. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [August 14, 2014, 1:44am UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/9 "2014-08-14T01:44:24Z")
> [@](#): > > Quoth **DrCube** : > > I’m not sure what you mean by that. I wasn’t clear, I suppose, that if a table is holding up the weight, or some other rigid object, it neither does work nor uses energy. Simply counteracting an external force doesn’t necessarily require an energy expenditure. But because of the way the human body is built – to be flexible along certain joints and therefore require muscular contraction to stiffen the body against a load – people do burn calories (i.e., use energy) while supporting a weight, even if they’re performing no work on the load. But then again, human bodies also burn Calories when not supporting any load at all. It’s misleading at best to say that Calories are being burned because of the supported load. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [August 14, 2014, 1:53am UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/10 "2014-08-14T01:53:08Z")
Just to help get a sense of how those [motor units take turns](http://www.ncbi.nlm.nih.gov/pubmed/8299601). > [@](#): > > Single motor unit potentials were recorded from the brachial biceps muscle of eight male subjects, during isometric endurance experiments conducted at relative workloads corresponding to 10% and 40% of maximal voluntary contraction (MVC), respectively. The recordings from the 10% MVC experiment demonstrated a characteristic time-dependent recruitment. As the contraction progressed both the mean number of motor unit spikes counted and the mean amplitude of the spikes increased significantly (P \< 0.01). This progressive increase in spike activity was the result of a discontinuous process with periods of increasing and decreasing activity. The phenomenon in which newly recruited motor units replace previously active units is termed “motor unit rotation” and appeared to be an important characteristic of motor control during a prolonged low level contraction. In contrast to the 10% MVC experiment, there was no indication of de novo recruitment in the 40% MVC experiment. Near the point of exhaustion a marked change in action potential shape and duration dominated the recordings. Each spike represents a contraction of a motor unit. Also of note the ATP energy is actually burned during the _relaxation_ segment of each motor unit contraction … contraction is an allosteric change as actin binds to myosin and fibers slide across each other … releasing it again takes energy from ATP. **Chronos** , at rest calories _are_ being burned because of the supported load. Muscles are never actually at rest. There are always some fraction of motor units contracting and others relaxing, each unit doing work over that time, even though, as in isometric contraction, no external work is performed. At rest fewer are contracting at a time is all. ---
**Author:** ![rsa](https://avatars.discourse-cdn.com/v4/letter/r/839c29/32.png) [@rsa](https://boards.straightdope.com/u/rsa)\ **Post date:** [August 14, 2014, 1:54am UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/11 "2014-08-14T01:54:49Z")
> [@Chronos](#): > > But then again, human bodies also burn Calories when not supporting any load at all. It’s misleading at best to say that Calories are being burned because of the supported load. Sure, balancing yourself and remaining upright requires a certain amount of energy. But balancing not only your own weight but also additional weight requires additional energy. ---
**Author:** ![Snarky\_Kong](https://avatars.discourse-cdn.com/v4/letter/s/a183cd/32.png) [@Snarky\_Kong](https://boards.straightdope.com/u/Snarky_Kong)\ **Post date:** [August 14, 2014, 11:32am UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/12 "2014-08-14T11:32:28Z")
> [@Chronos](#): > > But then again, human bodies also burn Calories when not supporting any load at all. It’s misleading at best to say that Calories are being burned because of the supported load. Calories burned while supporting load - calories burning without supporting load = calories burned due to supporting load. No? ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [August 14, 2014, 12:13pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/13 "2014-08-14T12:13:08Z")
> [@am77494](#): > > I get the physics behind - if you lift and hold a mass stationary, then no work is being done on the object. (for the time that it is held) This is only true if you do it in zero gravity. On Earth you are working against the Earth’s gravity. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [August 14, 2014, 12:18pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/14 "2014-08-14T12:18:43Z")
So can we finally put this canard to rest? The High School physics question that some here are answering is about the _external work_ done on the object - for the sake of High School physics homework there is no external work being done by the body on the 100 pound object being held stationary. Work equals force times distance. No distance, no work. Move on the question two about friction coefficients now. However, the op asks the real question, not that High School homework one: is there any work being done _internally_? And the answer there is a resounded most definitely **yes**. Multiple motor units within various muscles are repetitively contracting and relaxing, producing forces across distances many multiple times during the period, using energy to elongate, and then contracting again. The muscles as a whole stay one length, producing force but moving no distance (or in most realities very little self-corrective distances); the object moves no distance; but that gross effect is the result of much physics work, force along distance, occurring _within_ the muscles. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [August 14, 2014, 12:21pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/15 "2014-08-14T12:21:07Z")
> [@Quartz](#): > > This is only true if you do it in zero gravity. On Earth you are working against the Earth’s gravity. Only while you are actually moving the weight. [Work is force exerted across a distance](http://en.wikipedia.org/wiki/Work_(physics)); once you have raised the weight to its full height and begin holding it at a steady altitude, you have stopped delivering work to it. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [August 14, 2014, 12:24pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/16 "2014-08-14T12:24:37Z")
> [@DSeid](#): > > So can we finally put this canard to rest? Probably not - or at least not until we can school everyone on the physics concept of work (= F x D). ---
**Author:** ![Ranger\_Jeff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranger_jeff/32/2065_2.png) [@Ranger\_Jeff](https://boards.straightdope.com/u/Ranger_Jeff)\ **Post date:** [August 14, 2014, 1:18pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/17 "2014-08-14T13:18:58Z")
Perhaps the work done after lifting the 100 lb object and just being done while supporting it isn’t measured in Foot Pounds or Newtons?: ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [August 14, 2014, 1:20pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/18 "2014-08-14T13:20:36Z")
So no actually answering the actual question asked because some of you can’t go past question one of the High School Physics mid-term about external work performed on an object? (Not the question asked.) Can y’all get the idea that actual physics work (F x D), in the strict physics sense, is being done within the muscles? And that producing that work (and lost to heat) is where the extra energy needed to support the object goes. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [August 14, 2014, 1:51pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/19 "2014-08-14T13:51:10Z")
> [@Ranger\_Jeff](#): > > Perhaps the work done after lifting the 100 lb object and just being done while supporting it isn’t measured in Foot Pounds or Newtons?: Work and energy use the same units, since work is just energy transferral from one body to another via mechanical force. So if not foot-pounds or newton-meters, you’ll just be using some other unit that includes distance and force: calories electron-volts ergs horsepower-housr joules BTUs ounce-inches > [@DSeid](#): > > So no actually answering the actual question asked because some of you can’t go past question one of the High School Physics mid-term about external work performed on an object? (Not the question asked.) Can y’all get the idea that actual physics work (F x D), in the strict physics sense, is being done within the muscles? And that producing that work (and lost to heat) is where the extra energy needed to support the object goes. Haven’t you heard how shitty Americans are at science? And now you (and the OP) want to _complicate_ a fundamental question about mechanical work that most people already don’t understand, by making them also think about how muscles work at a microscopic level? And you’re surprised that people are struggling with it? 😃 It seems the OP’s question has already been pretty thoroughly answered, thanks in part to your excellent explanations of how muscles work: -No mechanical work is done on a mass held at constant altitude in earth’s gravity. -If the means of support for said mass is a living muscle that is actively contracting, the muscle uses chemical energy while it is exerting force; that energy is first converted to mechanical work which is dissipated, and ultimately manifests as heat, entirely within the muscle. ---
**Author:** ![flight](https://avatars.discourse-cdn.com/v4/letter/f/bbce88/32.png) [@flight](https://boards.straightdope.com/u/flight)\ **Post date:** [August 14, 2014, 1:52pm UTC](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442/20 "2014-08-14T13:52:35Z")
> [@md2000](#): > > A hovering helicopter or a rocket hovering on a flaming jet certainly is not using zero energy. Note that this is very different from the other examples as in this case simple obvious work is being done. Here it is just being done to the surrounding air and exhaust gasses. [Next page](https://boards.straightdope.com/t/i-hold-100lb-in-the-air-for-10-mins-do-i-burn-any-calories-do-work/695442.md?page=2)