what's here

final toe-push

see also

  

[ under construction ] 

 


intro

This is one phase in a detailed analysis of the sequence of moves for Leg-push motions of "normal  push" method of skating. For more context and an overview of all the phases of the sequence, see the summary of normal-push phases.

key points

  • Theme: Finish the leg Extension moves with maximum force -- and quickly. In phase 3b, start the Upper-Body-swing moves late with aggressive quickness, then try to set down the next foot early before this leg-push ends.

  • Knee-extension move (using the big "quadriceps" muscle) is often ignored, but it is critical for effective propulsion. Perhaps it gets overlooked, because it requires a (non-intuitive) "slicing" the foot forward relative to the hip -- and because it has the (also non-intuitive) ankle-flexion as its prerequisite.

The hip-extension and knee-extension moves work together in skating propulsion. Either one used alone is "aligned" ineffectively, but working together they can offset each other's misalignments, and produce a strong push out through the foot to the ground.

Actually it is not effective to go to "true" full extension of the length of the leg, because some of the muscle moves needed to achieve maximum length (e.g. ankle-supination, lateral-hip-rotation) if used in the Phase 3 configuration are either not propulsive or have bad side-effects for future phases.

  • Postpone the ankle-extension move as long as possible. Transmission of push-force is more effective through the heel of the foot. And the ankle-extension move is better "aimed" for propulsion after the leg is close to straight.

  • Ankle-extension move can also add a force to inline skates with the usual kind of wheelframe design (i.e., non-klap). (On an inline skate, perhaps this ankle-extension might be combined with a little outward-ankle-rotation move.)

  • Hold back on starting the Upper-Body-swing moves, and then start them with maximum quickness. The upper body parts being moved sideways should reach their maximum sideways velocity just as the next foot is landing on the ground.

Most skaters start the Upper-Body-swing moves much too early for maximum reactive-side-force contribution to propulsion.

Checkpoint: In a front view, try to have the center of each moving upper body part not cross the imaginary vertical line through center of the hips until after the other foot has been set down.

[ double-push ] - Timing is different for double-push skating. The start of Upper-Body-swing moves should be postponed until the last phase of the in-push, just before the Aim-switch phase A.

  • Overlap leg-pushes:  Play with setting the next foot down just before starting this final phase of the current foot -- so the early part of Phase 1 of the next leg is simultaneous with the later part of phase 3 of this current leg.

definition of this phase

??

This phase goes from (roughly) the start of focus on the knee-extension move. There may be some overlap with Phase 2. 

drivers of propulsion

[ physics and biomechanics parameters that drive the amount of added propulsion work -- and the additional time it takes to perform that work. ]

?? [ to be added ]

 

muscle moves

??

for forward propulsion:

also perhaps continuation of

details + hints

??

  • Push all the way out to full extension -- roughly to a straight leg.

On icy snow or wet pavement, full extension may not be possible, because edge grip is gets too difficult when the ski or skate gets too far away from the down-force from the weight of the skater's upper body.

  • Extending the knee joint is critical to getting maximum extension of the leg. The main muscles for this knee-extension move are the quadriceps.

  • Extending the knee joint pushes the skate or ski forward relative to the pushing hip.

The "magic" of skating is that it's possible to generate a backward push-force by pushing out toward the side on a skate or ski that is slicing forward.

For me it seems like the foot makes a circular arc relative to the pushing hip. In Phase 1b the foot goes back behind the hip. In Phase 2 the foot goes outward. Then in Phase 3 the foot continues to go out and also comes forward relative to the hip.

  • Skaters tend to ignore or forget this "forward slice" or "forward kick" move.

It feels strange because our natural intuition from walking and running tells us that the foot must move backward in order to push the body forward.

But the special "magic" of skating is that more extension of the leg out toward the side gets converted into more forward propulsion. This "forward slice" or "forward kick" is the true test of the skater's faith in the power of pushing out toward the side.

[ inline: skate teachers sometimes refer to this forward slice move as "carving", or as the final phase of the "C-stroke" push. ]

[ Bicyclists may note that it is also possible to use a "forward kick" move to add power to seated pedaling -- by starting to use the quadriceps muscles to push the pedal as it comes "over the top" of the circle. ]

3b - final Toe-push

??

There may be some overlap of this move with the moves in the early part of Phase 3, but I'm inclined to discourage this, in order to give emphasis to allowing the longest time for best transmission of big push forces through the bone structures of the ankle and heel.

[ inline: this phase does not apply to inline skates, unless they are klap-skates ]

muscle moves

??

for forward propulsion:

details + hints

??

  • Final push is with the ankle-extension move (often associated with the calf muscle).

This is the time for the heel to come up off the klap-skate or ski. The heel should stay down all through Phase 1 thru Phase 3, for best transmission of the big forces in Phase 2 and Phase 3.

  • Aim the push out toward the side, as a natural continuation of the forward-slice move of Phase 3.

Big Trap: When think consciously about the toe-push, it's easy to get into pushing only toward the back, and to forget the "forward kick" of Phase 3 which is needed to effectively gain maximum propulsion from the knee-extensor / quadriceps muscles. Therefore some instructors avoid mentioning the concept of toe-push, and recommend that most skaters just allow the proper motion to emerge naturally from consciously thinking about overall leg extension.

  • Play with setting the next foot down just before starting this final phase of the current leg.

So early part of Phase 1 of the next leg overlaps with later part of Phase 3 of the previous leg.

more . . .

other moves

It might be thought that these moves could add to the propulsive range-of-motion:

  • outward-hip-leg-rotation (or perhaps "outward-knee-roll") - [ see more ]
  • ankle supination - [ see more ]

because they extend the length of the leg -- provided there were opposite inward-knee-roll and ankle-pronation moves in phase 1 or phase 2.

But the direction of force from these moves is negative for propulsion in the leg-configuration and the start of phase 3. They do extend propulsive range-of-motion (and slow the fall of the skier's body mass and the fall of the hip) -- but at the cost of reducing the propulsive force.

There might be some large angle of the leg leaning away from vertical where adding these moves is a net positive for propulsive work, but I doubt at any leg-lean angle normally used for human skating (except possibly around a very tight curve?). Since it slows the stroke slightly, even if it is positive for propulsive work, it still might not be positive propulsive for propulsive power (the rate of work).

see also

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