Transitions.pdf

Lateral Balance & Transitions
The Cornerstones of Advanced Skiing

Topics
• Lateral Balance • Transitions • Targeting

Background
• For decades, skis were hard to turn
– Stiff skis – Soft snow – Focus was on how to get a turn started

• Now, skis are easy turn
– Great inclination – Big forces at end of turn – Linking turns is the focus

Linking Turns
• We’ll look at ski technique through the lens of balancing laterally and getting from one turn to the next • Look at turns from fall line to fall line, rather than traverse to traverse

Turn Mechanics
• To make a turn, you need a force to push on you from the side • You have to balance against that force by having at least one foot farther to the outside of the turn than your CM (inclination)

Turn Mechanics
• To go from a turn in one direction to one in the other direction, your CM has to swap sides with the point on its base of support from which the force is coming

Beginners and Wedge Turns
• Have very poor lateral balance • Need a wide base of support • When a ski pushes on them from the side, they need to have an “in-rigger” to hold themselves up • A wedge gives a skier such a base of support • The the turning ski grips much less than the skier expects, he doesn’t fall over • If the skier weren’t moving he would still be stable

Wedge Turns
• No need to make any big movements to link turns • There is always one foot to the outside of a turn in either direction

Wedge Skills
• That there is a force from the side that pushes on your outside foot • It builds as the turn progresses, the faster you go and the more you edge the ski by putting your foot farther to the outside • Develop a sense of the direction of the resultant, and how to balance against it

Wedge/Stem Christies
• Digression: The derivation of the term “christie” • At completion of turn, skier develops enough lateral force from the snow that to balance against it, his CM must get to the inside of both feet.
– Also depends on the pitch of the hill

• That’s what puts the skier on matching edges

Wedge/Stem Christies (cont.)
• If the skier weren’t moving, he’d fall over • If the turning ski grips much less that the skier expects, he falls over

Wedge/Stem Christie Skills
• Balance against bigger forces from the side • Incline far enough that you must be in a turn to keep from falling over • Estimate the amount of grip the skis will get

Basic Parallel
• Skis are always on matching edges • CM is always to the same side of both feet • Like learning to walk

Dynamic Parallel
• This is where snowboarding starts • Like learning to run

Technical Description
• Paths of feet and CM have to cross
– Cross-over/cross-under are technically the same thing

• How to do it
– Make path of feet tighten up – Make path of CM loosen – Combinations of both

Coordination of events
• Turn completion • Inflection point
– Neutral – Cross over / cross under – Edge change

• Turn initiation

Completion
• CM’s path starts to diverge from that of feet • Inclination starts to decrease

Inflection
• Path’s of CM and feet cross • Skis go flat • Begin pivot/redirection • Skier feels like he’s accelerating

Initiation
• Inclination increases • Pressure may start to build up • Skis can be displaced laterally • Leads to the apex of the new turn

Issues
• Requires great estimation
– How much will the skis grip? – How sharply will they turn?

• Skier’s subjective description is contrary to mechanical explanation • Once you’ve started, you can’t stop
– Pole plant – Inside ski

• Inflection Point is intrinsically unstable
– Skis aren’t on either edge

Techniques
• Make path of feet tighten
– Edgeset – Pre-turn

• Make path of CM loosen
– Flex

Targeting the Apex
• Determines when and how of the transition • Not restricted to racing

Apex
• The point at which you want the ski to begin aggressive engagement

Targeting the Apex
• From the most aggressively engaged, steeply inclined point of the turn, the skier must
– Know where the next apex is – Coordinate the movements of the transition to deliver her to the apex

Targeting the Apex (cont)
• Hitting the spot you want determines if you should extend or flex in the transition
– If there is enough time, extending has collateral benefits

Targeting the Apex (cont)
• Skier must arrive at the apex with proper
– – – – Inclination Fore-aft pressure distribution Edge angle Steering angle

Transition Problems
• Inaccurate targeting • Missing the spot
– Too much extension – Too much flexion

Transition Problems
• Fore-aft
– Too far back – Too far forward

• Inclination
– Too much
• Too far inside at the apex

– Too little
• Stem • Low edge angle

Transition Problems (cont)
• Steering angle
– Too much – Too little

Other Common Problems
• People throw ‘em sideways to reduce the period of no force • Uphill stem

Summary
• Much of learning how to ski involves learning how to change lateral balance from one side of the skis to the other • Dynamic parallel turns is where the rubber hits the road