What he said...
Originally Posted by sjjohnston
First, a small note: J4s are ordinarly 11 and 12 (and J5s are 9 and 10). The only 13-year-old J4s are those who just turned 13 because their birthday falls in 2009.
If you've got a J4 at the level (not mention the size) that he or she is using 170 cm skis, his or her coach must know him or her well enough to make some very specific suggestions.
It seems to me that the ordinary J4/J5 would be on a shorter all-around junior race ski, rather than an event-specific GS ski. These generally have very tight turn radiuses ... more like 13 meters. The length is going to depend on height and weight. Except in the case of very-early maturers, 12-year-old boys haven't yet got their adolescent growth spurt; 12-year-old girld may have, but often are very skinny.
...the coach should know best. There was an interesting article in Ski Racing, I think, recently, that said that most Masters racers and juniors are on way too stiff a boot, and there was a trend among top level juniors in the US toward softer boots.
You could almost (but not quite) say the same thing about sidecuts, lengths, construction, and all that good stuff for juniors as well. If you figure that the idea is to get younger juniors to ski well, carving turns, and so forth, and then worry about what to do in the gates...well, a ski that's too long, too stiff, or has too little sidecut is going to, potentially, inhibit that learning process.
On the other hand:
- The rules are the rules, and I don't currently know what they are for juniors. For Masters, I think the powers that be realized that requiring 70 year old guys to ski on a 186 cm. GS ski with 27 meters of sidecut was stupid...so the FIS regulations are merely "recommendations". So there's the junior ski rules, first and foremost, whatever they are.
- Second, there is an argument that the FIS came up with, and there's some credibility to it, that too many juniors were blowing their knees out because they were using skis with too much sidecut, which can lead to loading up the tail of the ski and having the ski arc out from under you...by by, ACL. There's also kind of a theory that too much sidecut can be a crutch...you can sort of buy a turn, which means you can get away with an unbalanced stance (sitting back), and other technique faults...which will show up, big time, when you go to a bigger ski with less sidecut.
- Third, along the same lines as the above point, if at some point a junior is going to ski FIS events...well, eventually you're gonna have to deal with the FIS regulations. Unless I'm reading things wrong, the new Atomic catalog shows a 181 cm. GS 12 with a 27-meter sidecut...and you can guess this might be something suitable to a lighter boy, say a J1/J2, who is good enough and whose points are heading him for direct entry into some FIS events in the near future.
- Finally, if you want to talk speed events, that's a whole different ball game. Speed events for kids is a tough one, but what I do know is it ain't a great idea to try to try to do junior speed events on a long GS ski. You really need a laminate, flat tip, speed ski construction in the appropriate length and sidecut for the individual athlete. Yeah, I know...more bucks, but if you want your kids to ski fast and safe, they need the right gear...