OT - q for exercise physiologists

I noticed people huffing and puffing in our fitness center and I got really curious as to how much calories a weightlifter burns.

Got home, did some internet based research, and found “scientific 0”. Of course, there are multiple listings for “moderate” and “vigorous” exercise, but no one discusses metrics of such. For example, 200lb gentleman in really good shape moving 200lb of metal just has to burn more than 200lb flubber ball moving 50lb, even though their definition of effort might be similar.

So, amount of calories burned would have to correlate to:

  1. Weight and distance moved
  2. Probably time that the effort takes comes into place as well - since the weight is both raised and lowered, not just dropped
  3. Muscle mass, not body mass

    Anyways, does anyone know of any table correlating, say, moved weight to calories burned?

I’m no physiologist or whatever …
… but “muscles” are better if toned for endurance rather than size , that is unless one wants to dead lift rediculously heavy objects for brief periods of time .

Cardio is what’s important for endurance and athletic rec. sports .

Ride a bike up a hill , paddle up river , walk up a mountain side … you’ll build up weaker muscles , burn calories , strengthen the heart , build endurance .

I just don’t see how weight lifting is good for much more than bulking up … don’t see it as a way to burn off unwanted extra body fat and get fitter .

If one is concerned with losing body fat (as in calorie counting), instead of thinking weight lifting to burn calories off … think eat less and do cardio endurance sweating stuff , I think .

It’s not much
The work done to lift 200 pounds by 2 feet is 400 pound-feet.

Work and energy are interchangeable.

400 pound-feet = 0.13 Calories. This is the energy done on the weight.

The body is maybe 60% efficient at converting food to work, so 1 rep burns maybe 0.2 Calories.

Weight lifting
Doing “resistance exercise” or weight-lifting is the most effective (time/effort) way to lose weight and stay in shape.

Aerobic activity definitely raises the rate of calorie burn, but resistance activity raises the rate of calorie burn MUCH HIGHER, and causes the body to build muscle mass which raises the calorie burn rate even higher, even when not exercising. The greater one’s muscle mass, the higher the calorie burn rate that is needed to sustain it.

Think of a car engine. A 4-cylinder engine will use much less fuel than an 8-cylinder engine. If you keep putting gas in the car and not using it, it is stored (FAT). If you have a 4-c engine, you have to run it a long time to burn the extra gas. If you put an 8-c engine in there, you will burn the extra gas a lot faster.

So you can spend 10 hours a week doing aerobic exercise or spend 3-4 hours a week doing resistance and have similar results.

A balance of both is ideal.

Here you go

Somewhere on here you can search for that. But as stated above, weight lifting intensely for the same period as cardio will burn more. That is because you keep burning well after you quit lifting. Whereas, for cardio, when you quit, you quickly settle back into steady state mode and your increased calorie burn stops. To burn fat however, you must incorporate HIIT training, an advanced form of cardio.

3 sets of 30 mins. , 5-10 min, breaks
… repeat , go again .

Set is riding bike up hill , paddling canoe up river , walking up mountain … first 20 min. heart pounds , there after heart only pounds under increased pace when pushing much harder .

I wonder how many calories this type activity burns over the course of a day out playing , as compared to an hour in the gym on weights ??

200 lb for 2ft is 536 Joules. Or 0.13 Calories ( not to be confused with calories). Human body is typically taken to be ~20% efficient, hence exercise would result 0.64 C. It is safe to assume that energy is consumed to both raise and lower the weight, with less expenditure to lower. Let’s call it 1C then.

So, that is math that does not account for huffing and puffing. And, I was looking for some physiological data, not pure calculations.

Physiology versus “work”

– Last Updated: Nov-13-09 1:13 PM EST –

There is more to muscle physiology than just the amount of work performed as defined by mass moved a certain distance against the force of gravity. The process of muscle contraction doesn't "care" one bit about how much mass is moved against gravity, but it DOES care about tension generated within the muscle. Here's a simple demonstration: Hold some kind of heavy object (an outboard motor, a brake drum from your 18-wheeler, ANYTHING heavy). Support it in any way that you wish, even with one hand and the arm just hanging down at your side, but do not raise or lower the object. Eventually, your muscles will reach total exhuastion and feel like they are on fire, yet you haven't even done ANY work as work has been defined by other posters.

I just rememberd, one of my old gymn teachers used the "arm hang" as one of his fitness tests. That works out the same way. You just grab the chin-up bar with your hands and let yourself hang there as long as you can. Do this JUST ONCE and the next day you will feel like you seriusly over-did it while lifting weights, yet the amount of effort expended by those over-taxed muscles works out to "zero" using the methods cited above.

of course
This the reason why asked if anybody knew of tables/formulas, articles.

An example of calculations is a few posts up, courtesy of mintjulep.

Still doesn’t account for everything

– Last Updated: Nov-13-09 4:11 PM EST –

I guess I didn't make myself clear. Biochemical work and physical work can only be roughly compared for "typical" speeds of muscle motion during lifting. AGAIN, the TIME for which a muscle must maintain tension is just as important as how much tension is generated, but the "force x distance" calculation ignores that aspect of the problem.

Using the other poster's example of 400 pound-feet per lift, imagine that a person can lift that weight for the defined distance for 30 repetitions before reaching the point of total exhaustion where the muscles are no longer able to continue. During each repetition, the muscles would do 400 pound-feet of work. Now, if that same person were to do everything the same, except that they reduced the speed of lifting and lowering by a factor of 10 (so each repetition takes 10 times as long), they would still do 400 pound-feet of work for each lift, but the number of repetitions that could be performed before the muscles reached their limit would be a small fraction of the number when lifting at "normal speed". The muscles would reach total exhaustion for the same reason as before, and would reach that point after expending a fairly similar amount of biochemical energy as before, but after doing only a small fraction of the "physical work" as before. The amount of physiological work (related to biochemical energy expenditure) that is done is very dependent on the time for which muscle tension is maintained, just as it is on the amount of muscle tension that is generated, but the amount of physical work is dependent ONLY on the amount of muscle tension and the distance over which the force is applied. The effect of how much TIME the biocemical process is maintained is ignored when looking only at pound-feet. I'm sorry that I don't have actual data tables to quantify this, but I'm simply pointing out a very basic biological fact, that living things expend energy during the entire time period that tension is maintained in a muscle. In the world of physics, the time during which a force is applied (through non-living support members) is not relevant, which is why calculation of the amount of work done in the field of physics is so simple (force x distance).

In short, physical work and the amount of biochemical energy that must be expended to perform that work can only be compared as "averages", and the accuracy of those averages diminishes drastically as soon as you start altering the time frame of muscle exertion.

good point -arm hang
I paid a trainer for a begniner assessment and she emphasized weight training. Build muscle and burn calories. I like the idea of my tummy is like gas tank on car. Lots of miles on car and do not add much fuel, especially late in day and your car-tummy-has lost weight. On orbiat precorefx, I can burn over 1,000calories in one hour. On quickstart, about 800 in one hour. It is about adrenalin. If sports or politics, rev your motor…

In the world of physics, the time during which a force is applied (through non-living support members) is not relevant

Not quite true - consider dissipative systems.

Simplest analogy - think hydraulic actuator. You need to supply constant pressure to even hold static load.

Explain please

– Last Updated: Nov-14-09 10:20 PM EST –

There are all sorts of hydraulic devices which "hold" with no energy input at all, at least until tiny amounts of leakage have enough cumulative effect to be noticed (such as hydraulic jacks, the brakes on your car, and hydraulic excavation and drilling equipment. Even the hydraulic press we use to test concrete at work, a remarkably compact machine, will maintain 350,000 pounds of force for long periods with no energy input at all, as long as you close the control valve prior to shutting-off the pump motor). I admit that I don't know what you were referring to, but it seems to me that if a hydraulic device NEEDS constant energy input to maintain a steady, non-moving force, it's by design, not due to some inherent characteristic related to the hydraulic transmission of force. The same cannot be said for maintaining constant force by means of muscles.

In biological systems, there ARE ways of maintaining a constant force without constant energy input, but they make use of very special "locking joint" mechanisms which remove muscle tension from the design (or reduce it to a minuscule degree), so that the force can be maintained by, or primarily by, the structural integrity of support members themselves (the joints of the pectoral fins of many catfishes are a perfect example of this, and the human knee joint "trends" in this direction when we are simply standing fully upright and stationary).