 Poster: A snowHead
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Who's been to one of these?
How was it?
Fun? Useful? Not cold/slushy/moguly enough?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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I do feel that the prices of the uk skiplex i looked up once a couple of years ago were quite high? I don't recall exactly. For comparison in any case: at my slope 10 lessons (10 times 30 minutes, but taking up an hour with breaks in between) costs 175 euros. A separate lesson is 20 euros.
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Speak to Tubaski, think he's spent so much time there that he's worn it out 
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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Everything that @JulieAimeLeSki says. I spent the entire summer last year relearning to ski at Skiplex and I think it's great as a workout for your ski muscles and also excellent for working on your technique so I completely recommend it. As with any artificial surface it is a bit different from snow and you have to adjust your feel. It's not as forgiving as snow but I've seen videos showing that if you can do it on snow, you can do it on the moving carpet. My summer training programme includes weekly sessions there as well as trips to Hemel. Currently paying £60 for 4 sessions per month which I think is great value. I always enjoy it but T shirts not ski jackets are de rigueur.
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Ha, @SnoodyMcFlude, not too far from the truth, I reckon I've done about 60 hours (much of which was on the summer pass last year). I'd echo what @motyl and @JulieAimeLeSki say above.
My skiing certainly progressed a lot quicker as a result of using skiplex. It's good if you use it (and the instructor) as a tool - but it compliments snow, it can't entirely replace it.
I'd say its good for building strength and for beginners to early intermediates to really get parallel nailed. Obviously it's not going to be any good for long radius carved turns. I'd certainly go back to work on some specific things (e.g. short turns, steeps). Speed goes up to about 25kph I think - which is quite fast enough in a small space - and pitch is adjustable from flat to approx a steep red (certainly steeper than Hemel).
Unfortunately the experience does vary depending on the ability of the person you are sharing the slope with...
Price wise, if you think of it as a lesson, the value isn't bad - especially with summer offers. If you just want to do some skiing lift passes at Hemel work out cheaper though.
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@Tubaski, never been on one, have no intention either but why is it no good for long turns (other than having no "g-forces" to play with) and as you're not going anywhere - why would the slope speed matter (i.e. not >25kph)?
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@under a new name, because the slope (at least the Chiswick one) is only 8 or 10m wide I think (the room it is in used to be a squash court) - the skis I was using last year had a radius of 12m.
I didn't say the speed mattered, in fact I was making the point that the speed was adjusable and fast enough (for me). And of course the speed is the linear speed of the belt in the fall line so your speed across the slope is actually a bit faster. Trust me, 10mins solid of doing 4m radius turns at 25kph is quite a workout. That's basically a 4km run of shortish turns!
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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| under a new name wrote: |
| ... why is it no good for long turns (other than having no "g-forces" to play with) ... |
Isn't that the main point though? To get our skis on their edges we have to move our body to the inside of our feet so the skis tip sideways. With limited g-forces (because we're not travelling that far around the arc of turn) there's not much to balance against, so there is a big limitation to how much we can move our centre of mass to the inside of our feet.
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@rob@rar, so that would apply to any carved turn really, no?
@Tubaski, I thought that by
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| fast enough in a small space |
you were suggesting the space had something to do with it. Which I didn't understand.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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| under a new name wrote: |
| @rob@rar, so that would apply to any carved turn really, no? |
My physics education is a long way behind me, but any turn where we need to get our centre of mass significantly inside out base of support will require g-forces (which I'm sure I should probably call centripetal forces) in order to stay in balance. Without those forces we have to compromise to stay upright (e.g., excessive angulation, using the inside ski as an in-rigger). This applies to any kind of turn, carved or not, when our CoM needs to be inside our BoS.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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| under a new name wrote: |
@rob@rar, so that would apply to any carved turn really, no?
@Tubaski, I thought that by
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| fast enough in a small space |
you were suggesting the space had something to do with it. Which I didn't understand. |
Well I think it probably does rather.
If you only have 8-10m width of "piste" to work with, you don't want to be traveling stupidly fast I would have thought.
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Maybe I am misunderstanding the whole skiplex concept but I didn't think you were actually travelling at all ...
My treadmill doesn't care how fast I run (I do of course, and would care more if something went wrong...)
That would be my thinking @rob@rar
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You know it makes sense.
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| Quote: |
My physics education is a long way behind me, but any turn where we need to get our centre of mass significantly inside out base of support will require g-forces (which I'm sure I should probably call centripetal forces) in order to stay in balance. Without those forces we have to compromise to stay upright (e.g., excessive angulation, using the inside ski as an in-rigger). This applies to any kind of turn, carved or not, when our CoM needs to be inside our BoS.
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Hi Rob, we had this discussion a couple of years ago in another thread, but what you say ihere is, i'm afraid, incorrect. It's entirely possible to generate 'g forces' while stationary compared to the surface of the earth providing the surface beneath the skis is moving relative to the skier.. I'm not going to rehearse the arguments from the last time round, but look at the photo
The guy at the top clearly has his centre of mass outside the bases of his ski
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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| under a new name wrote: |
Maybe I am misunderstanding the whole skiplex concept but I didn't think you were actually travelling at all ...
My treadmill doesn't care how fast I run (I do of course, and would care more if something went wrong...)
That would be my thinking @rob@rar |
Unlike your treadmill you are travelling side to side, so if you lose it at speed you can potentially fly off the side into the barrier/wall. I can confirm that happens 
And of course if you fall onto the belt you are relying on the instructor stopping it quickly enough to stop you flying off the back edge into that barrier (to be fair they are good at stopping it quickly).
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Poster: A snowHead
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It's entirely possible to generate 'g forces' while stationary compared to the surface of the earth providing the surface beneath the skis is moving relative to the skier.
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I really don't think it is...
Pictures can be deceptive.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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So, you're all in agreement then, wrt skier movement relative to surface underfoot 
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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| motyl wrote: |
| So, you're all in agreement then, wrt skier movement relative to surface underfoot |
. Edit: Ah missed that last post... !
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You need to Login to know who's really who.
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I've heard it's great for littlies - as much skiing as they can handle without the faff of shuffling around and tiring out climbing back uphill. I have my own doubts about the physics myself and based on Chemmy Alcott's promo video clearly she didn't find it completely natural. But I guess I'd need to try it rather than writing it off. Can definitely see the value as a fitness tool - I bet 5 minutes at a fair speed/slope is pretty challenging.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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So, the 'G forces' we experience when sking are the resultant of the varous forces directly acting on us. These (IIRC) are as follows with comments in brackets being how these differ in the skiplex environment.
1) Gravity (pretty much the same, we are still on Earth)
2) Reaction force from the surface/snow (by managing this we turn, so similar once you compensate for differences in other forces)
3) drag from surface (greater on skiplex as snow is slippier than the mat, plus see below)
4) drag from air (lower at skiplex as not moving forward through air)
The difference between skiplex and the hill is the moving mat which compensates for the moving down the hill. This must be an additional force transmitted to the skiier through drag on the skis to prevent loss of altitude.
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You'll need to Register first of course.
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Developing that thought further...
Take a section of hill the same width and as a skiplex slope where the set pitch is identical to the hill, and then do an identical set of turns down the hill and the skiplex slope. The only difference at the end of this is that you end up at a lower altitude on the hill but the same altitude on the skiplex slope.
This means that greater forces have acted on you on skiplex, since your loss in altitude on the hill is due to unmatched gravitational forces.
When we talk about G forces in turns we mean the experience of moving from a low G force as we gain speed accelerating into the fall line and the higher G force as we turn out of it, it's that variation we enjoy (right?)
I think the general (and valid) point about the variation in G force in turns being less on Skiplex is actually as a result of the practical limitations of the environment in terms of the shape and size of turns you can make, and not anything to do with the movement of the surface. It is not correct to say that these forces are not present.
As an aside, if you could make a skiplex slope much wider, so that you can carve a 19m radius turn for example, I think you would also need it to be longer as the time spent accelerating into the fall line would mean that your velocity down the slope would deviate further from average, meaning that you would move up and down the slope more in the course of the turn.
It's been a long time since A level physics though, so perhaps I've missed something...
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| Dave of the Marmottes wrote: |
| Can definitely see the value as a fitness tool - I bet 5 minutes at a fair speed/slope is pretty challenging. |
Yep!
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@Tubaski, "g" force is actually a misnomer. g as a force is gravity. "pulling "g"s" is just because all accelerations feel the same i.e. you can't differentiate between force due to gravity and force due to equal acceleration.
So if you're not moving relative to the earth, you are however applying frictional force on the moving mat against gravity (otherwise you'd slide to the bottom). Now, whether lateral movement across the mat will allow sufficient centripetal force to allow you to get your centre of mass inside your base of support I don't know but I don't think so.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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| Quote: |
| And apologies to the OP for the thread drift! |
Withdrawing the apology as I've just noticed the OP was @admin presumably trying to ferment discussion  Drift away....
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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| Tubaski wrote: |
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| And apologies to the OP for the thread drift! |
Withdrawing the apology as I've just noticed the OP was @admin presumably trying to ferment discussion Drift away.... |
That made little sense as I accidentally edited rather than quoted my original reply to UANN, here it is...
| under a new name wrote: |
| @Tubaski, "g" force is actually a misnomer. g as a force is gravity. "pulling "g"s" is just because all accelerations feel the same i.e. you can't differentiate between force due to gravity and force due to equal acceleration. |
Indeed, and I do know that but couldn't be bothered to try and reframe the terminology, especially as I was typing on my phone at the time
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| So if you're not moving relative to the earth, you are however applying frictional force on the moving mat against gravity (otherwise you'd slide to the bottom). |
I'm not sure about the exact terminology here, but in principle yes I agree.
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| Now, whether lateral movement across the mat will allow sufficient centripetal force to allow you to get your centre of mass inside your base of support I don't know but I don't think so. |
Centripetal force is a resultant force from gravity (which is acting on you, irrespective of whether you are moving downhill or not) and the reaction force from the surface. Back to the point in my previous email, if you do the same set of turns on the hill and on Skiplex the physics are broadly the same, except less reaction force from the surface means you end up at a lower altitude.
So if you ski linked short turns in a 8m corridor down a moderate red run at an average downhill velocity of 25kph would you be able to get your centre of mass inside your base of support? If yes, then why would you not be able to do that on Skiplex?
And apologies to the OP for the thread drift!
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Developing that thought further...
Take a section of hill the same width and as a skiplex slope where the set pitch is identical to the hill, and then do an identical set of turns down the hill and the skiplex slope. The only difference at the end of this is that you end up at a lower altitude on the hill but the same altitude on the skiplex slope.
This means that greater forces have acted on you on skiplex, since your loss in altitude on the hill is due to unmatched gravitational forces.
When we talk about G forces in turns we mean the experience of moving from a low G force as we gain speed accelerating into the fall line and the higher G force as we turn out of it, it's that variation we enjoy (right?)
I think the general (and valid) point about the variation in G force in turns being less on Skiplex is actually as a result of the practical limitations of the environment in terms of the shape and size of turns you can make, and not anything to do with the movement of the surface. It is not correct to say that these forces are not present.
As an aside, if you could make a skiplex slope much wider, so that you can carve a 19m radius turn for example, I think you would also need it to be longer as the time spent accelerating into the fall line would mean that your velocity down the slope would deviate further from average, meaning that you would move up and down the slope more in the course of the turn.
It's been a long time since A level physics though, so perhaps I've missed something...
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I agree with all of this. The loss of potential energy experienced by the skier on the fixed slope compared to the skier on the moving slope will be equal to the energy expended by the motor powering the moving slope.
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So if you're not moving relative to the earth, you are however applying frictional force on the moving mat against gravity (otherwise you'd slide to the bottom). Now, whether lateral movement across the mat will allow sufficient centripetal force to allow you to get your centre of mass inside your base of support I don't know but I don't think so.
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I think your analysis is correct but your conclusion is wrong. Ther forces built up against the moving carpet will increase rapidly as the skiers relative speed across the carpet builds up (through setting the slope at higher angle and running the carpet faster). There will be plenty of force available to get the skier's weight inside the skies at higher 'speeds'. It's just the same way as on the snow where dynamic skiingis only possible at higher speeds.
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You know it makes sense.
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Not been on Skiplex but back in the 90's there was a similar system. The mat was shorter and much narrower, still had adjustable incline and speed but you used shorter skis than normal due to the size of the mat.
It was def a good workout, we where demoing it at the ski show and never forget him saying how easy and effortless it was while we where pouring with sweat. So yes these mats are a great workout, you can generate force but not to the same degree as on snow but not too far removed from plastic.
The main issue with generating more force is that it is the mat/surface that does most of the movement not the skier so while on snow turning your angle of movement to the fall line changes if your edges hold this movement changes to going across the slope but if you do not hold an edge then you still have some movement down the slope and this is what that mat was like.
If you hold your edge firmly you rise up the mat and vice versa if you do not hold it. So it is a balancing act.
Start with skidding your turns and feel how the edges grip and try and stay vertically central on the mat. Once you can do that and at your level this will be very quickly to almost instantly just have fun and play. You can then stagger of at the end
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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No,
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| Centripetal force is a resultant force |
from e.g.holding a piece of string and spinning it around your head. The centripetal force is applied to keep the weight moving in a curve and has nothing to do with gravity.
@Spud9,
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| The loss of potential energy experienced by the skier on the fixed slope |
will (friction and any other work done aside) equal the kinetic energy of the skier before they do work to come to a stop.
If the skier on the moving slope doesn't move, they aren't changing their PE but they are doing work, to resist the pull downwards from gravity and allowing the slope to move under them. And I can't get my head round the equations on that 
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There will be plenty of force available to get the skier's weight inside the skies at higher 'speeds'.
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Maybe. Certainly possible.
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Poster: A snowHead
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| under a new name wrote: |
No,
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| Centripetal force is a resultant force |
from e.g.holding a piece of string and spinning it around your head.
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Yes, it results from the force holding one end and the force causing the far end to move. This results in a torque causing the loose end of the string to move in a circle
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| The centripetal force is applied to keep the weight moving in a curve and has nothing to do with gravity. |
I disagree, The centripetal force is a result of the force from the snow preventing free-fall (equivilent to holding the end of the string) and the force of gravity providing the acceleration down the slope.
I didn't word that very well, but the link below explains it much better...
Look at section 3.2 here: http://www.nzsia.org/downloads/nzsia-section-3.pdf
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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@Tubaski, ah, you are using a specific definition. I was being rather more general
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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@under a new name, I thought it was the reverse
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You need to Login to know who's really who.
You need to Login to know who's really who.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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Do they, like bike rollers or Gym treadmills, have videos to give the impression of downhilling?
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You'll need to Register first of course.
You'll need to Register first of course.
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| Arctic Roll wrote: |
| Do they, like bike rollers or Gym treadmills, have videos to give the impression of downhilling? |
That'd be quite cool (although most of the treadmills in my gym mostly give the impression of Jeremy Kyle and the Kardashians)
Actually you ski facing a mirror, which can be quite revealing - especially if you have any odd habits...
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So if I get this right you'll travel faster on the mat I.e progress downhill by skidding turns rather than strongly edging? As a better edge set will have you gripping the mat more?
That'll drive racers nuts.
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@Dave of the Marmottes, I was told last week that the reason a 10 year old (or thereabouts) was racing down to the front was because he was carving and therefore accelerating beyond the speed of the mat. I may be wrong but I think a degree of skidding is needed to control speed, much like on snow I guess 
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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| Quote: |
| Jeremy Kyle and the Kardashians |
that well-known popular beat combo...
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| motyl wrote: |
| @Dave of the Marmottes, I was told last week that the reason a 10 year old (or thereabouts) was racing down to the front was because he was carving and therefore accelerating beyond the speed of the mat. I may be wrong but I think a degree of skidding is needed to control speed, much like on snow I guess |
Yep, and it's generally only kids and midgets that use skis short enough to carve for more than a very short section of the turn, (although occaisionally they let big people ski on the short skis for some fun)
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FAQ
but my country has a lack of snowy mountains and this is a way to get the moves in. I can write novels on this topic but in short, if you don't expect skiing in the traditional sense but love moving, the muscles, the technique (partly, because some things are out of reach, such as moguls indeed) then i find that a skiplex type indoor slope that is near to you is not a bad option. It has made me happy and continues to do so. I also ski on indoor snow frequently and will be trying dendix from september on.
