Theory on Resistance Bands

[HyperionGauss]

As we all see on commercials, resistance band machines show big buff guys working out on things like Crossbows and Blowflex (oops, Bowflex). And as most of us with an IQ above 70 know, the whole resistance bands concept doesnt work. My friend was stubborn about this and wanted to know "why", since resistance is resistance according to him. Now, the resistance band don't offer that much resistance at all and I decided to put up my theory on why it doesn't, please add if you think I'm wrong or right.
When you work out on a resistance band machine, it kind of like pulling a rubberband. Easy to pull at first, but as you stretch it out farther and farther, the rubberband becomes harder to pull, so the resistance increases as you pull. So in a Bowflex, the metal bar bends easily a first, but the more bent it becomes, the harder it is to push it.
The difference between this and freeweights is resistance CONSISTENCY here. When you bench press 200 pounds with free weights, it's 200 pounds from beginning to end, positive to negative, providing constant stress on your muscles. But with a resistance band machine, the 200 pounds isn't consistent. It can't possibly be, since the bow will always bend easier at the beginning of the rep and the farther you do the positive of the rep, the more resistance you get. So if you were to set 200 pounds on a bowflex, your only pushing 200 at the very end of the positive motion (e.g. the "farthest you can stretch" of a rubberband). The resistance only increases as you go through the rep and isn't consistent. Same with the negative portion, the weight is only peaked at the beginning of the negative, and slowly lessens until there's no resistance at all by the time you reach strarting position. To sum it up, your not stressing your muscles as much as you set the weight to until you reach the very peak of the positive.

Just thought I'd add that after reading so much stuff of these resistance band machines that people think they should get because they offer "65+ Club Quality excercises". What they don't tell you is the repetitiveness of half of these excercises (if you look on the Cross bow site for excercises, there's about 10 different ways to do curls, as an example).

[HyperionGauss]

any price comparisons between blowflex and free weights?

[Wojtek_da_Hulk]

this is actualy a very good theory

you are correct IMO, but i still think that there is a lot more than that to it

[BoxSquat]

I strap rubber bands to my weights... best of both worlds

[HyperionGauss]

Originally posted by BoxSquat
I strap rubber bands to my weights... best of both worlds

good one :-D

[IeatSteak]

Bowflex uses POWER RODS!!!

[HyperionGauss]

i know it uses power rods, dumbass, but they work the same way as rubberbands

[IeatSteak]

Originally posted by HyperionGauss
i know it uses power rods, dumbass, but they work the same way as rubberbands

errr yeah, nice attitude! you must be so popular!

[diplomat]

ur an idiot do u even have a bowflex? I do and its not like u described. Theres resisitance all the way thru cuz its not a rubber band. obviously u know nuthing about rubber bands because if anything there would be lest resitance at the end. the farther u stretch a rubber band the more elasticity so getting it started would be harder.

[SlammaJamma]

Originally posted by diplomat
ur an idiot do u even have a bowflex? I do and its not like u described. Theres resisitance all the way thru cuz its not a rubber band. obviously u know nuthing about rubber bands because if anything there would be lest resitance at the end. the farther u stretch a rubber band the more elasticity so getting it started would be harder.

What you said about rubber bands being easier to stretch at the beginning is wrong, but what you said about the bowflex is right. You don't stretch the the rods, u bend them. At the beginning of the movement (first few inches), the resistance is slightly less, but after that it is consistent.

[EAE]

Originally posted by diplomat
ur an idiot do u even have a bowflex? I do and its not like u described. Theres resisitance all the way thru cuz its not a rubber band. obviously u know nuthing about rubber bands because if anything there would be lest resitance at the end. the farther u stretch a rubber band the more elasticity so getting it started would be harder.

Actually rubber bands are harder stretch the more you stretch them, but of course you'll learn that when you reach high school. You'll also learn that any solid compound will want to return to it's original shape. In the case of non-malleable substances like wood, it would just break if you applied enough pressure. More malleablesubstances like metal's can bend without breaking, though if it's a strong metal then it will be harder to bend and will return to it's original shape.
The power rods are malleable, and as you bend them more you will have to provide more force because it is trying harder and harder to return to it's original shape (just like ... rubber bands!). So yes, there is more resistence at the end.
But like I said, you'll learn all this when you get to high school.

[IeatSteak]

Originally posted by diplomat
ur an idiot do u even have a bowflex? I do and its not like u described. Theres resisitance all the way thru cuz its not a rubber band. obviously u know nuthing about rubber bands because if anything there would be lest resitance at the end. the farther u stretch a rubber band the more elasticity so getting it started would be harder.

Uh oh....Hyperion got busted!!

[ZachG_85]

Well, bowflex doesn't work like that. It would be great if it did, band training is something powerlifters do.

Bowflexes suck because resistance ISN'T just resistance. Stabilizers are involved, it's like doing everything with a cable machine.

That machine will NOT let you do the following: decline bench, dumbbell curls, pullups, squats, deadlifts, barbell rows...

Because of the nature of the machine, it's impossible to vary your grip. As such, close grip/wide grip anything is impossible. You can't do thing overhand or underhand. Tricep work is limited to pressdowns. Chest is limited to a cable fly or a cable bench. You can do leg presses with light weight.

Oh, and if you ever get even marginally strong they're useless. I've hopped onto machines and been shoulder pressing more than the thing can hold.

Also, have you EVER tried lateral raises with a cable? It's damn near impossible. Unilateral movement on a bowflex is impossible because you have no way to balance yourself.

[Travis Stenersn]

You're bang on with bands exerting more force when you stretch them more.

If any of you have taken physics, you'll remember that F=kx when it comes to springs. Same deal here.
edit: (f=force k=a constant depending on material properties and x=the extension or the stretch in the band or sprint)

With free weights, the force is proportional to the mass times the acceleration. F=ma

Now this doesn't mean that bowflex won't work. It will work fine, for muscle gains.. for a few weeks. Then it becomes necessary to vary training goals for continued progress. ie periodization. The problem comes in at this point. There is only so much variation with bowflex that you can do. Plus, it won't really translate into the ability to come to the gym and use the same amount of weight because, as you pointed out, there will be a huge strength deficit at the start of any movement, because of the bows exerting less force at that point.

Could you build an impressive physique with a bowflex? Probably. Would it be harder than it would be in the gym? Almost definately.

Do bands have some properties that make them a useful tool to integrate into your program.. definately!

[BoxSquat]

Originally posted by diplomat
u know nuthing about rubber bands because if anything there would be lest resitance at the end. the farther u stretch a rubber band the more elasticity so getting it started would be harder.

Actually all the bands i've ever used get harder the more you stretch them, that's WHY i use them

[HyperionGauss]

Nice posts. For the people who said that the rubberbands are easier to stretch at the beginning...er, I don't know what to tell you. Must be unlike any rubberband I've seen. Some people like to use the rubberband like system, but on things like a bowflex it's useless because as was stated after a few weeks it's near impossible to gain any more. As for diplomat and ieatsteak, yes I have used a bowflex, making this theory without having used one would be somewhat difficult.

[diplomat]

i didnt say they were easier to stretch at the beginning i said they were harder.

[nybble]

i use bowflex and i say the force is constant throughout the whole motion, therefore u are all wrong.. jk jk.

[SlammaJamma]

Originally posted by Travis Stenersn
You're bang on with bands exerting more force when you stretch them more.

If any of you have taken physics, you'll remember that F=kx when it comes to springs. Same deal here.
edit: (f=force k=a constant depending on material properties and x=the extension or the stretch in the band or sprint)

With free weights, the force is proportional to the mass times the acceleration. F=ma

Now this doesn't mean that bowflex won't work. It will work fine, for muscle gains.. for a few weeks. Then it becomes necessary to vary training goals for continued progress. ie periodization. The problem comes in at this point. There is only so much variation with bowflex that you can do. Plus, it won't really translate into the ability to come to the gym and use the same amount of weight because, as you pointed out, there will be a huge strength deficit at the start of any movement, because of the bows exerting less force at that point.

Could you build an impressive physique with a bowflex? Probably. Would it be harder than it would be in the gym? Almost definately.

Do bands have some properties that make them a useful tool to integrate into your program.. definately!

Good post. The only thing is, although f=kx for springs, I don't think the bowflex rods work like a spring (or rubber band). You don't stretch the bands, you bend them. Think about it. The amount of force needed to bend the band would vary depending on what point you are bending to (I know, I'm not explaining it well). Regardless of what it looks like, the resistance is quite consistent, although not 100%.

[Travis Stenersn]

When I rethought my post, I figured that bowflex likely didn't work exactly like that. Honestly, I don't totally know how it works. I am not good enough at physics to really explain it.

[nybble]

f=kx pertains to all things that flex. picture a vertical bowflex rod ontop of a y-axis. now picture bending that rod to the right or left. now draw a perpendicular line from the top of the rod to the y-axis and measure it, that is the value 'x'