# whats the calories burnt in weight training??



## new_apprentice (Apr 1, 2004)

hey guys,

im doing some calculations for my weight lose which i am going to be starting next week. ive built up some good size now but want to shread off the fat thats covering my new muscles!!!!!!!

im trying to work out how many calories im burning compared to my calorie intake.

i can find loads of figures for cardio exercises, for example how mant calories i burn if a run for an hour, but none for weight training.

i train pretty damn hard on the weights so i recon i must be burning some good amount of calories

does anyone know how to help me here?

cheers guys:confused:


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## Jimmy1 (Aug 14, 2003)

thats another piece of string question mate


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## philipebrown (Nov 26, 2003)

im sure i read that 1 hour intense anaerobic worked out about 4-500 kcals but like jimmy said there are so many factors that would affect that


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## Guest (Aug 13, 2004)

i would guess that it (1hrs heavy lifting) would burn no less than 300kcals, and no more than 600kcals.


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## Jock (Apr 8, 2003)

TBH you should forget about calorie numbers and concentrate on your diet.


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## hackskii (Jul 27, 2003)

Jock said:


> TBH you should forget about calorie numbers and concentrate on your diet.


Class!


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## Hallso (Sep 4, 2004)

on average 300 calories are burnt doing rigourous weights training per 45 minute session assuming no more than 1 min. breaks are taken between sets.

remember thats on average, if you fart about doing lower weights, then you'll burn few calories.


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## zoidberg (Sep 14, 2004)

Hi new_apprentice,

Here's the science:

1 Joule is the work required to lift a mass of 102g a distance of 1 metre under the Earth's gravity.

So to lift 1Kg for 1 metre you will do 1000 / 102 = 9.8 Joules of work.

Say you can bench press 100Kg (way more than I can but it keeps the maths simple).

You will do more work on the positive part of the rep than the negative part but let's assume that your press exertion is averaged out over a 1 metre distance.

Each press you perform will do 100Kg * 1m = 980 Joules of work.

There are 4.184 Joules in 1 calorie so each press will do 980 / 4.184 = 234 calories.

Say you do 5 sets of 10 reps at this weight:

234 * 5 * 10 = 11700 calories

Now remember that food ingredients and daily calorie requirements are actually quoted in Kilocalories (1 Kilocalorie = 1000 calories).

So that gut-busting bench press session just burned off a measly 11.7 Kcal !!!

The good news is that your muscles are not perfect energy converters - it takes more than 1 calorie's worth of food consumed to produce 1 calorie of useful work at the muscles.

Your body burns calories in 3 ways:

Quoted from

http://www.trinewbies.com/Article.asp?ArticleID=51

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The thermic effect of feeding (TEF) is approximately 10% of total metabolism and includes obligatory thermogenesis (the result of the energy-requiring processes of digesting and absorbing food) and facultative thermogenesis (the activation of the sympathetic nervous system and its stimulating effect on metabolism). The TEF can vary greatly depending on both the quantity and type of food eaten. TEF is usually not a primary factor in changing body weight because of its low relative amount of contribution to total metabolism.

The thermic effect of physical activity (TEPA) is approximately 15-30% of total metabolism and includes occupational and lifestyle activity (what you do at work, running errands, etc.), and purposeful exercise (training). This is the most variable component and can contribute significantly to weight loss and weight gain. More exercise=more calories burned=more weight lost (if you control the amount of calories you eat). This is what many of you experience when you first begin training--you lose weight because you are burning more calories than you are eating.

Resting metabolic rate (RMR) is approximately 60-75% of total metabolism and includes sleeping metabolism, basal metabolism, and arousal metabolism. RMR is the amount of calories your body burns at rest to perform basic functions such as your heart beating and your brain functioning. RMR is the most important component on the calories out side of the energy balance equation because it represents up to ¾ of the total calories burned by the body.

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So if your daily recommended calorie allowance is 2500 Kcal then between 70% and 85% of these are used in non-exercise-related functions:

70% = 1750 Kcal (people with low resting metabolic rate)

2500 - 1750 = 750 Kcal needs to be burned by all physical activity.

85% = 2125 Kcal (people with high RMR)

2500 - 2125 = 375 Kcal needs to be burned by all physical activity.

There is still a gap in this explanation but hopefully this helps in understanding how calories work.

Cheers,

zoidberg


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