It seems to me that the only good pivoting footplate is on the Powerskip Pro.

Yeah, drill some holes and lock it.  If you feel like getting the running advantage from them, then you can unlock them later, but it seems that they've misplaced the axle.

They probably have it placed for little underfed Chinese people's feet...

Oh, they would still experience pressure because they are stuck between the force of the spring and the inertia of your body.  I think weight may turn out to be irrelevant or at most insignificant in this question.  I think it's more a question of how much weight it takes to bottom out one spring.  That amount would be the maximum amount of force the spring can put out, which would also be the maximum amount of force your leg experiences.  Body weight wouldn't matter much because the spring would accelerate a light body much faster than a heavy one, making the same compression force between the spring and the inertia of the body regardless of what the body weighs.

Here is a detailed explanation of why Dome's springs are so wonderful.  If they aren't that impressive to you, you should read this.

It's a question of how much energy is lost in the form of heat in every bounce, and the relative strength of the spring at different levels of compression.  For those of you who have not taken physics yet or took it too long ago, an "ideal" spring will give a force of X pounds at Y inch compression distance, and 2X pounds at 2Y in.  This is what the character of a cheaper spring equates to.  The higher-quality springs are more like .75X pounds at Y inches and 3X pounds at 2Y inches, with force increasing much more than it "should" as compression increases.  This makes them very soft and smooth for walking around and jogging, but still have the power to fling you high in the air once you start bouncing.  Better springs are soft at the top of the compression and stiff at the bottom. 

The mystery springs are more extreme in this non-ideal behavior than any other spring on the market by a lot.  They are so soft right at the top that you land very smoothly and hardly have to brace yourself when you land.  This is very nice because a lot of the energy lost in a bounce is lost in that moment from all the shockwaves that shoot through your body.  If you look back at the video, you will notice that Dome receives no shock from landing.  He goes down very gracefully, and then the springs shoot him right back up again with very little energy loss.  If you look at people on other springs, there is a noticeable impact on their bodies when they hit the ground.  The impact is smaller on 7leagues and Powerskips, but still visible.  The other side of the non-ideal spring behavior is being very stiff at the bottom of the compression.  This is the only way to pack great power into a spring whose first few inches are soft enough to comfortably run on.  If you look closely at the video, Dome experiences much more acceleration at the bottom of the compression than he does at the top.  At first, he only slows down a little, then the spring stops him very quickly and shoots him back up.  I also noticed that as his jumping height increases, the distance he compresses the springs increases less and less per added inch of jumping height.  That's two pieces of evidence pointing to the fact that those springs really don't want to compress the last few inches.  This is why the springs are so wonderful.  I could have simply stated that they are very soft at the top and very stiff at the bottom, but that would have been far too concise for the likes of me.

By the way, he mentioned a "turbo" function for the last little bit of the spring.  In case you didn't catch what he meant, it's an extension of the non-ideal behavior i explained above.  He intends on making the springs extremely stiff for the last little bit of the compression.  It may feel a little rough at first, but it would be much better than bottoming out.

If you were in the USA, I'd buy them from you for $260 for my sister.  That's around 115 pounds, I think.

Not really a much bigger selection in Europe, the only brand you can't get in the USA is 7leagues and even then you can get them with a big shipping fee.  That isn't really important to the thread itself, but I just thought I would point it out.

Wow, those look WONDERFUL!  I think most of the physical strain from bocking comes from the immediate shock of landing, but those springs are really smooth on the landing.  They look really soft at the top of the compression and really stiff at the bottom.  I think that will make them very easy to use.  If they aren't too expensive, I hope to buy a pair when my current springs wear out.

And by break security, do you mean having some protective piece on the spring to keep the wearer from being injured if the spring breaks?

I think the rumor about unusually stiff Poweriser springs comes from the spring review, in which the Poweriser springs had not been broken in yet.  I'm 72kg on 7090 springs, and now that they are broken in, I think they are just right.

The Poweriser Advanced is definitely the highest quality on your market.  The deal isn't as good over there as it is in the USA, though, by about $70.  I think the AU dollar is about equivalent to the USA dollar right now.  If the AU dollar is still a little less, then it's about the same price.  The Powerizers are about   I don't think you will regret getting the Powerisers, but I have no idea about the Powerizers as I have never used them.

I suggest you do not get Airrunners.  They should have stayed a prototype until about now; a remake of the Airrunner has just been released in Germany today, I think.  Airrunners just aren't very good.  Wonderful concept with many nice design ideas, but they reportedly come together as awkward and not nearly what they could be.  I am hopeful about the new version, but don't expect to see it any time soon.

Jeez, how long have you had those?  That is DEAD.  Hmm...  What weight class springs do you have on those?  Cuz if you did that with Raptor springs, your bocks had better be pretty old or 7leagueboots has issues with the strength of that part.

That IS a pretty finnicky part to begin with, or at least it is on my bocks.

I think the springs lose a little more energy in a bounce than other brands,  but otherwise they'll be fine until something wears out, which may happen unusually fast, depending on how lucky you are and how much Skyrunner has cleaned up its act since they got their reputation.  I've noticed that all the cheaper brands have improved greatly over time, so there may be hope.  When something breaks, you can always buy the replacement part from a nicer brand; pretty much all parts are interchangeable.

Very, very interesting...  Very, very goofy-looking gray protective layer.  Did they drop the cuff idea or are they having patent issues?  All of the new jollyjumpers have kneebars.  The skimpy hooves look like they're way lighter than anything ever on the market, including the old Up-Wing design, but they also look like they'd wear out even faster than normal.  I'd say just stick with the old Up-Wing hoof, but maybe pick a different color from orange.  Either that or make the rubber thicker.

Otherwise, very sexy and very shiny, lots of black, they look like you could shoot out shockwaves of pure awesomeness by kicking the air, but we'll have to wait and see if they actually deliver.

My biggest concern is the fold-up feature someone mentioned a while ago.  If they're made to fold up at the heel for more compact transport, I'm a little worried.  That design is already fragile enough without an extra joint.

Yep, if you're experienced, you'll be probably able to handle the 7090s.  They will be quite stiff at first, but after they're broken in, they will give very nice height.  Stronger springs take some getting used to and some strength to use, but they can put out more power, good for extreme stuff.  If the m70s are plenty for you, then maybe 5070s might be OK, but they will be softer than m70s.

EDIT: actually, I've heard that FL springs are a little on the soft side, so maybe not.

If you want stock cuffs, Poweriser 08 and Velocity stilts are the only options, unless you want to try Up-Wings out, but I don't think those are really cut out for flipping, although they are nice and light.

Few if any people who have tried Up-Wings liked them for one reason or another, and Velocity Stilts are more expensive than Powerskips, so Poweriser 08 is probably what you want.

By the way, you can flip on pretty much anything.  Good bocks are not necessary, although they do make it easier.  Also, if you meant you want metal for the block that the knee bindings go into, they come with anything that has cuffs.  Kneebars have some stability of their own which cuffs lack, so the metal block is only necessary for cuffs.

I discounted Skyrunner because they aren't on the market in patent-protected countries, that's all.  Well, officially not on the market, but the vendors usually neglect to say that.  Nasty surprise if you find out that Skyrunner has your money but customs had them destroyed.

Piggybacking two springs would be extremely stiff and prone to breaking if you ever manage to bend them at all, it seems to me.  Well, that's if they're right on top of each other; they'd be working like one monster spring with the back one entirely in tension and the front entirely in compression.  If they had a few inches between them so they can work separately, I think they'd work OK, but piggybacking them brings up a whole new set of engineering puzzles, and it seems like it would be a lot more complicated than side-by-side.

Yep, Martin's right.  We answer the same questions over and over here, and you seem to have not noticed the Knowledge Section.  It's on the tabs near the top, or maybe also on the side bar since you're new.