Jump techniques in racing.

[Ross Biff]

I watch with interest the difference between a skiercross racer squashing a jump by pushing their arms down between their legs and bringing their knees up towards their ears and a dh racer bringing their knees up towards their chest and dropping their hands to the outside of their ankles. Why???

 

[4ster]

I think the dynamics are different in each event as the speeds & slope pitch are so much different. The skier cross competitors are riding it more like a pump track and doing their best to absorb the lip & stay in contact with the snow.

Other times they need to pull their legs up hard to double or clear a gap.

The downhillers are also trying to stay in contact with the snow but because of high-speed's and the terrain big air is inevitable. The hands by or behind the ankles being more for aerodynamics. Daron Rahlves was the first DHer l remember doing it instead of keeping hands & arms forward. At least that’s my take on it.

 

[Ross Biff]

I see were you're coming from re the aerodynamic aspect, given that speed suits are illegal in skiercross. I can also see that the repetitive nature of the consecutive jumps would maybe require a different set of techniques. I would love,however,to see skiercross in speed suits but I understand there is some resistance to this from the baggy clothed brigade

 

[Jack skis]

DH racers are going many miles per hour faster than skiercross runners, traveling much farther through the air, and farther off the snow. So speed, distance travelled in the air, and height off the snow probably require differences in technique. I say probably because I can't really argue for the correctness of my statement, never having raced a real DH or even been on a skiercross course.

 

[hbear]

Seeing both up close the SX athletes are the ones getting bigger air (higher off the ground), the racers travel further off a jump but that’s a function of going way faster in DH/SG. No lip/kick off the racing jumps (ground just falls away) while the SX does certainly send their athletes into the sky with jumps designed at inclines.

 

[hbear]

I’m guessing here, but likely due to SX being a bit of a survival sport. It’s you vs the pack vs the clock so likely those little things than mean hundredths of a second are not quite as important as say, staying on your skis and not crashing into tor competitor before the next feature or when you are 4 across a big gap in the air.

I know they do practise what looks like a traditional jump movement in training, but suspect all hell breaks loose in the throws of a real race.

See if I can remember to ask the SX team athletes next time I see them.

 

[Ross Biff]

I’m guessing here, but likely due to SX being a bit of a survival sport. It’s you vs the pack vs the clock so likely those little things than mean hundredths of a second are not quite as important as say, staying on your skis and not crashing into tor competitor before the next feature or when you are 4 across a big gap in the air.

I know they do practise what looks like a traditional jump movement in training, but suspect all hell breaks loose in the throws of a real race.

See if I can remember to ask the SX team athletes next time I see them.

That would be interesting to get the SX racers perspective on this. All hell breaking loose indeed! Maybe a better chance of holding it together during a good mid air shoulder charge with a potentially wider base of support?

 

[razie]

I watch with interest the difference between a skiercross racer squashing a jump by pushing their arms down between their legs and bringing their knees up towards their ears and a dh racer bringing their knees up towards their chest and dropping their hands to the outside of their ankles. Why???

Given that they use poles...

Having coached both, the basic principle of jumping in both is minimizing air time (unless in SX you have features to time and jump over or line/turns or other tactics to handle etc) and landing in balance, in order to maximize control and speed... and there are specific techniques, which revolve around absorbing the lip - either straight up absorbing, which is common in SX and pre-jumping - common in speed.

The SX jumps are generally taken at lower speed, with turnier skis (~21m), with the line crowded by the other racers, often focused on landing quickly to setup for the next tight turn and maybe pumping something off the back of the jump. The more you absorb and the faster you regain control, the better the results. The speed jumps are focused more on flying in control and landing in balance (~40m or more radius skis).

In both cases, you drive forward and down with the arms and suck up your knees... but it makes sense that the speed jumps are more out of control, since any impulse on take off will unsettle the body more and cause corrections fore/aft and lateral.

So, the SX racers would I guess more often suck up their legs more, for absorbing without flying while the speedsters would prejump more in control... thus they would look slightly different.

p.s. there is an interesting demonstration and discussion of pre-jumping techniques in the "physics of skiing" book, as I remember...

p.s.2. I found this, but it doesn't get into jumping techniques in detail: http://ussx.org/wp-content/uploads/2015/05/ski-cross-manual-copy.pdf

p.s.3. Taking off on a jump off a bump is also useful when there is a @razie in the way and you'd rather jump him - wink, wink, you know who you are... I believe @Noodler witnessed that razie-jumping technique...