Parallel skiing and stuff

Thursday, June 26. 2008
Ski Coaching

There is an interesting conversation going on in the "comments" section of the "Ski Coaching" category, much of it relating to whether or not skis really can be skied truly parallel. There is a mixture of enlightenment and confusion. If skiing interests you, you could do worse than take a look.

In reply to David's comment (no.9) I'd say that what John Shedden so wisely observed about the skis, after the initiation of the change of direction, having to respond to centripetal (and presumably other) forces, then perhaps the forces on the inner and outer skis are different.

We might expect them to be, whether or not the two arcs were congruently centred, but certainly so if they are because the "moment arms" will be different. I think. Perhaps!.

If this is the case, and if the force on the inner ski were to be automatically more than that on the outer ski because of its tighter radius, then it would bend more. In that instance it would then perhaps be able to describe an arc parallel to the outer one, which at the same time could have its centre point the same as the outer ski.

What do you think? What do our resident physicist suggest? Is there anybody there? Knock three times for yes.

Bob

Posted by Bob Valentine Trueman in Ski Coaching at 08:35 | Comment (1) | Trackbacks (0)

Parallelism

Monday, June 23. 2008
Ski Coaching

In very minor response to John Shedden's post, [ it's immediately below and you really should take a look ] the only thing I have to say that might be worth listening to is that the skis' parallelism would not I think be related to the shape-outcome of the arc; not at any rate if the timing, the rate, and the amplitude of the skis' tilting and other responses were the same as one another.

Does this make any sense? If I'm not careful I might get so far up my bum that I won't be able to get out and ski!

Bob

Posted by Bob Valentine Trueman in Ski Coaching at 01:58 | Comments (0) | Trackbacks (0)

Parallel skiing revisited again, but this time by the master.

Monday, June 23. 2008
Ski Coaching
I have just received an email from John Shedden in response to our discussion on parallel skiing and whether or not it is possible. John has had a bit of a problem getting this post to load, so I have simply attached his commens in full to this post.
If YOU are having any similar difficulty please just email me at bobski@bobski.com
From John,
Could that be m(wsquared)     divided by r ?

We talk about circles for ease of conversation but What if the arcs are not circular but some other conic section?  Or even perhaps made up of several different sections of conic sections.
The arcs do have different "centres" if the legs are working independently of each other as each arc relates to each leg..or?

Perhaps  so called parallel skiing is vastly overrated as the only thing the skier has (more or less) complete control over is the INITIATION of the change of direction.  This is the focus of most peoples attention when learning and the rest of the 'turn' is subject to a variety of forces to which the skier will respond.  

Parallel 'starting' might be better named as simultaneous 'edge change' - (or as I might call it, simultaneous tilting. Bob ) - the initiation phase --followed by the reactive / steering phase - until the next initiation phase.

I can't speak for anyone else but when I steer my skis, even when I'm carving, I travel along curving 'pathways' which often change shape during a single 'arc' - if that isn't a contradiction in terms.

I supose what I'm saying is that we TALK about, "arcs" and "radii" etc because it makes conversation possible but theose words are just shorthand for more complex things going on . . we shouldn't believe everything we say!!


Very best regards,
John
Posted by Bob Valentine Trueman in Ski Coaching at 01:50 | Comments (6) | Trackbacks (0)
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