Also I've recently (Feb 2007) learned that there are new Poweriser Pro model that makes some engineering improvements on the original, but I don't yet have a pair to play with.
In April of 2009 I learned of another manufacturer, in Oregon, that sells what they call Air Trekkers. They seem to have ratcheted up the sophistication level, in that they have three models and a much finer-grain of spring strengths (10 kg increments). They have both the older-style metal knee-braces as well as the calf cuffs. Their springs are carbon-fiber instead of fiberglass. My experience with carbon fiber is that it's a bit stiffer but lighter and less prone to degredation over time.
I've played with a few of these different stilts, owned by people I meet with them. Mostly I have experience with the Korean ones, which I describe below. I think most of this experience is broadly applicable to jumping stilts, but YMMV.
Despite being 1/3 the cost of the German stilts, the Korean stilts are not cheapo toys. They're well made, feel very solid. So far they've taken a fair amount of abuse from me without repairs. However, they do have some shortcomings, though they're easily addressed. See below ...
When I got the Powerisers, I had difficulty getting any bounce. Some of the parts were rubbing, and each bounce sounded like Canadian geese honking. Some spray graphite fixed that.
The Powerisers are 'one size fits all', with two spring-strength ratings: 50-70 kg (130-160 lb), and 70-90 kg (160-220 lb). I'm 160, so I got the stiffer springs -- but I'm at the low end of the range, so I have to work em pretty hard to get any bounce going. I figured out that the trick is that you really have to stomp on em hard, because they're a lot stiffer than a trampoline.
Here are some of the modifications and supplemental equipment I added:
The foam on the knees is much too fragile. I wrapped them with the tape I use to wrap my hockey stick.
Similarly, the springs are wrapped in rubber, which also gets chewed up easily. I used the same tape here.
I didn't like the way the knee brace was much larger than my knee, so I got some knee pads to fill that out. The pads make the most extreme usage comfortable on the knees. The stilts have red and black colored bits, so I got some reversible red/black pads. I've heard that you can get really thick skateboard kneepads that are even fatter; maybe I'll get some.
I place them so that the bar hits them in the middle of the extra knee padding, just below my kneecap.
The built-in strap is a piece of crap IMO, so I made some straps. I started with just lengths of nylon webbing. My trapeze instructor made me the straps shown here. On the right is the first version, with a plastic buckle. One of the buckles broke so he made me the second version, with a metal buckle (left).
I start with the webbing behind my calf.
Then cross over the bar ...
Then wrap behind the knee and repeat.
The webbing straps just tie off in the back, so they aren't bouncing around visibly.
Here's one of the black straps, on my right knee. It's a shorter strap, so it only goes around once, and I put the buckle just beyond the very front of my knee so I don't risk landing directly on it.
Good to go ...
Side view ...
Next up, backflips.
If you're going to try flips, I recommend learning them on a trampoline first (layouts, not tucks). I use wrist guards, elbow pads, and a bike helmet, as you see here. I have access to safety lines at a trapeze school in Oakland (Trapeze Arts), and hired an instructor to keep me off my head until I was confident I wouldn't crash badly.
Oops! I rarely land my first flip attempt. I still get butterflies before I launch, so I don't take the trick up high enough. One fall is usually sufficient, though. :-)
Damn, that's fun!
Haven't worked out front flips or baranis yet.
I can run pretty fast on em too, but so far I haven't figured out exactly how fast. More fun, I think, is taking big bounding strides -- not so fast, but very high, kind of like walking on the moon.
Thanks to Hunny Bunny for the photography. :-)