[BoxingFanNoMore]

Originally Posted by Mav3rick

Supporting your bodyweight does in fact have everything to do with it. You are recruiting more muscle fibers by supporting your body and moving it through the desired distance as opposed to cycling where you recruit primarily the muscles of the lower extremities. Run a mile one day and track your heart rate. Cycle a mile one day and track your heart rate. Compare the two and you will see there is a big difference in heart rate levels, providing you tried to keep a relatively comparable pace.

I prefer cycling when I'm not concerned with sport specific training. It has a lower intensity and yes it is easier on the joints of the lower extremities. The key is finding what works for you. Research and theories are guides, they aren't substitutes for personal experience.

I think we have a different definition of supporting bodyweight. The term weight means force, bodyweight is then the vertical force created by your mass as a result of gravity.

So are you arguing that supporting this force while running makes it supperior to cycling and swimming?

The vast majority of expended energy has to do with propelling your mass forwards while, swimming, cycling, or running. Not supporting your bodyweight vertically, I think that is pretty straightforward, have you ever seen a cheetah run, it spends very little time actually making contact with the ground, so a majority of the time it is not actually supporting its weight at all.

But here you go in scientific terms.

"We find that 70–90% of the increase in energy cost with
speed in bipedal runners can be explained by the increase in
rate of force generation. The direct proportionality between
****bolic rate and 1/tc supports the theory that ****bolic rate
increases at higher speeds because faster, ****bolically more
expensive, muscle fibers must be recruited to produce force."

Pretty straight forward, 70-90% accounts for generating force to create linear momentum. Also, faster you go more energy you expend because you have to create more force for shorter contact times.

Shorter contact times means less time supporting your bodyweight, according to you that would mean less energy used.

But hey what do I know, I guess I should stop rowing then and go running with a weight vest on.

[TJ Combo]

Thanks a lot for the answers so far.

[TJ Combo]

Originally Posted by johnnynoname

agree. especially 400meter sprints.

here's a great article on intervals

http://www.t-nation.com/readTopic.do?id=459414

Does anyone have some experience with that 400-meter-sprint system? Cause to me it sounds a little bit too easy just to sprint a couple of rounds per week and then losing fat.

The last two weeks I have been doing 2 hours cycling sessions, 4 times each week. Along with that I did some muscle exercises. I don't see much results in my goal to lose fat although I ate almost nothing and left out all sweets, limonades and stuff like that. I lost two kilograms though.

[Evilness]

Nothing beats running, IMHO

[Mav3rick]

Originally Posted by BoxingFanNoMore

So are you arguing that supporting this force while running makes it supperior to cycling and swimming?

I'm not saying anything is superior to anything. Your previous statement appeared that you were saying that bodyweight has no effect on intensity when in fact it does.

How many humans do you know that run as efficient as a cheetah? We, for the most part, spend more time on the ground. The greater our mass the more force we have to reverse on each foot contact. How much force are we working against in cycling? We aren't reversing our mass against gravity, only exerting enough energy to rotate the pedals.

Original poster asked about efficiency in fat burning. Lower intensity exercise will burn fat more efficiently than high intensity training that uses muscle glycogen for energy production. Draw your own conclusions.

[BoxingFanNoMore]

Originally Posted by Mav3rick

I'm not saying anything is superior to anything. Your previous statement appeared that you were saying that bodyweight has no effect on intensity when in fact it does.

How many humans do you know that run as efficient as a cheetah? We, for the most part, spend more time on the ground. The greater our mass the more force we have to reverse on each foot contact. How much force are we working against in cycling? We aren't reversing our mass against gravity, only exerting enough energy to rotate the pedals.

Original poster asked about efficiency in fat burning. Lower intensity exercise will burn fat more efficiently than high intensity training that uses muscle glycogen for energy production. Draw your own conclusions.

I already stated weight wil be a factor, one factor out of many. Weight will be a factor because it is a measure of mass therefore a measure of inertia.

Humans may not be as efficient as cheetahs, but world class runners usually run at a Froude number(Ratio of Inertia forces/gravitational forces) at 3.2. Most people switch from walking to running at 0.5.

Yes you do some work against gravity in the arial phase, but then gravity does work on you to pull you back down, in fact your center of gravity is pretty constant, and the body acts like a spring mass system. Thats the problem your legs work like compressed springs putting stress on your joints.

The fact is during running you are doing the majority of work creating horizontal forces, not supporting your body weight.

This is in the results study that actually measured the horizontal and vertical forces of runners.

"This perturbations on the ****bolic cost of running should
suggests that the ****bolic cost of generating horizontal propulsive forces during normal running constitutes more than one-third of the total cost of steady-speed during level running."

also,

"Generating horizontal forces was more expensive per unit of force than was generating vertical forces"

Originally Posted by Mav3rick

How much force are we working against in cycling?

Are you serious, lets see there is rolling resistance, mechanical friction, and most important drag.

Not to mention that you are propelling not only your mass but the bikes mass as well.

[johnnynoname]

Originally Posted by TJ Combo

Does anyone have some experience with that 400-meter-sprint system? Cause to me it sounds a little bit too easy just to sprint a couple of rounds per week and then losing fat.

The last two weeks I have been doing 2 hours cycling sessions, 4 times each week. Along with that I did some muscle exercises. I don't see much results in my goal to lose fat although I ate almost nothing and left out all sweets, limonades and stuff like that. I lost two kilograms though.

Actually I would increase the frequency from what the author of the article suggested.

I would suggest 400m sprints once a day , only taking a rest day when your body tells you to.
Futhermore you may want (if you want to be hardcore) try 2 a days. Again only once a day is enough but I know that i've gotten insane results with two a days

Also i would suggest doing them on a empty stomach in the morning before breakfast.
Why?
After an overnight fast your body's glycogen levels are at its lowest. Meaning that with your body exercising in a somewhat depleted state of glycogen your body will quickly tap to your bodyfat stores for energy.

[Mihail]

Originally Posted by BoxingFanNoMore

in fact I know some NFL players who compete in triathlons in the offseason to stay in shape(and get shitloads of free stuff from sponsors & prizes).

Who are they?

[Mihail]

Originally Posted by Evilness

Nothing beats running, IMHO

Running is not easy on the body at all, especially in heavier people.

[TJ Combo]

Originally Posted by johnnynoname

Actually I would increase the frequency from what the author of the article suggested.

I would suggest 400m sprints once a day , only taking a rest day when your body tells you to.
Futhermore you may want (if you want to be hardcore) try 2 a days. Again only once a day is enough but I know that i've gotten insane results with two a days

Also i would suggest doing them on a empty stomach in the morning before breakfast.
Why?
After an overnight fast your body's glycogen levels are at its lowest. Meaning that with your body exercising in a somewhat depleted state of glycogen your body will quickly tap to your bodyfat stores for energy.

Do you do the sprints without warming up at all? Just going to the track and start the sprints?