Le…Propulski.
I knew it was only a matter of time before someone had the guts to try something like this. Introducing…Propulski! (English only readers, click here for Google translated web page.) Coming out of France, Propulski is a removable spring that is used with tech AT bindings (seems like they might work with some telemark set-ups as well?) located under the center of your boot that literally…propels you forward.
The Propelski is a pretty simple idea and the springs are placed on a post that the user mounts under the center of there boot. The mechanics are obvious. Step down and load up the spring…stride forward and let the spring’s return energy push you. Obviously, one could see the Propulski having some troubles in deeper snow, and it might not be the beneficial if you’re packing bigger AT setups. The Propulski weights only 100 grams (per pair), costs $118USD (90 Euro…plus shipping) and the company claims multiple benefits.
– Conserves energy and reduces fatigue on the uphill, giving you more strength for the descent.
– Improves forward movement and allows one to go uphill faster.
– Aids in softening impact for comfort and aged knees, as well as other joints.
– Reduces friction between foot and boot since there is less effort when striding.
– Increased efficiency and forward travel outweigh the 100g of extra weight.
Le storage bag, springs and mounting hardware .
There is a short video on the Propulski website that shows how the springs are used and a user review claims that although the springs weigh 100g, he thinks the benefit equates to 300g, with every step. He also states that once you try it…you won’t back to skiing without it.
Purists (like Randosteve?) will no-doubt chuckle and turn up their noses to the Propulski, but I almost wonder if this contraption is only a half-step towards something even more revolutionary when it comes to AT bindings and backcountry skiing propulsion. It seems to me that someone, with a brain much bigger than mine, might be able to turn this concept into something a bit more elegant. I doubt I see myself using the Propulski for most of my skiing, but I might see myself using it for long missions into the Winds or on other long slogs on flatterish terrain.
Interesting. I wonder how kick turns would work?
jared…i don’t really see kick turns being an issue. kick turns usually mean you are going uphill and most likely using one of you heel risers. when using a riser, you aren’t really compressing the spring.
$110 for two little springs and a couple of screws? Damn. Call me crazy, but I think I could find something cheaper to “propelski” perhaps a PBJ sammy….
Snake oil. Stepping on springs all day will kill your joints. Same reason they dont make spring loaded running shoes.
brock…totally agree on the cost of these things. could probably go to the hardware store and make something for a fraction of the price.
That’s an interesting post-hole simulator. Think about it
The propulski doesn’t interest me much, but I have often thought about some sort of mechanism that pushes one’s skis onto the snow while skining, in order to prevent excessive lifting of the skis. I think that could be a real energy saver. But maybe the activeflex dynafit boots help with this?
jasper…i think good skinning technique reduces the amount of ski-lift you get when skinning. my skis barely leave the snow when i skin.
Aaron, they do make running shoes w springs…. ever heard of the ‘air’ or ‘pumps’ lines from major manufacturers? the problem w springing a runners stride is the complexity of the the heel strike – lateral arch roll – tranverse arch to toe thrust mechanism that a simple spring cant match.
Eric the difference between a post hole and a spring is that a post hole is not a spring in the mechanical sense. think about it
Mark,
Those air, gel, or eva inserts in the midsole of a sneaker aren’t meant to rebound (function as springs). They are meant to absorb and dissipate impact forces as heat (function as dampers/shock absorbers). Shoes with actual springs have been tried, with little (or no) success over the years. Even the impact absorption offered by modern sneakers has some problems. I’ve switched to Merrell barefoot style shoes and I think my stride is much smoother, more powerful, more stable, and more efficient due to putting my feet in a natural (zero drop) position.
Dynafits in their current form allow for pretty good stride mechanics. Better than any frame binding, better than any tele setup, and pretty close to an NNN or Salomon XC ski binding.
If a spring under the boot worked so well, XC skiers would have adopted them a long time ago. Considering the increased efficiency of running in zero drop shoes and the XC ski community’s continued use of neutral (zero drop/ramp & no springs) bindings, I’d say this product is at best not helpful and at worst could cause more joint strain for users.
I suspect that most people wishing they had springs under their feet just need to log some more vert and improve their technique.