This page summarizes the most important video analysis checkpoints for the most common skating styles + situations. Although some of these are tricky to observe accurately, some others of these are fairly straightforward to observe in a front view or side view (provided you analyze only the segment of a side view video where the camera viewpoint was roughly 90 degrees from the side).

I've marked the trickier observations as:  [ not easy to observe ]

what's here

with Poles

  

[ under construction ] 

 


standard-form perception for Normal-push

The purpose of this "standard-form perception" style of skating is not to be the fastest style. Rather it is to educate and test perceptions where the brain tends to get fooled, and moves which feel unnatural for many of us.

overall

  • timing synchronization: The other foot is already set down on the ground before this leg lifts off. The Set-down of the next foot should occur before the Finish of the current foot's pushing: "overlap" timing. [ see more ]

Key reason for this overlap timing is that the newly Set-down foot helps to support the weight of he upper body, so it's easier for the other pushing leg's hip to spend more time in a lower position -- so a larger proportion of the force from the big Extension muscles goes directly into propulsive Work. This weight-supporting role of the non-pushing foot can be emphasized by setting it down straight in the direction of the skater's overall forward motion, then pivoting it to aim diagonally (outward for Normal-push, inward for Double-push).

set down

  • front + foot-aim views:  Set-down with ground-contact vertically underneath center of hip.

  • foot-aim view:  Set-down with hip + knee + ankle + ground-contact all in line. (front view: knee slightly outside of hip-ankle line)

  • Gentle into setting down. Motion speed and direction of the foot immediately before Set-down should be roughly the same as after Set-down. No stomping downward. No quick forward move from Recovery into Set-down.

  • front view: foot aiming straight in the direction of the skater's overall direction of forward motion.

This is to help feeling comfortable with the other (pushing) hip spending more time in a lower position, and holding back the start of its Extension push. Emphasize perception of the weight-supporting role of the foot just set down. Then pivot the foot to aim diagonally (outward for Normal-push, inward for Double-push).

Except this doesn't work so well on long cross-country skis on snow, because pivoting is costly.

  • front view:  Pelvis facing forward, with the two hip joints roughly level.

  • front view:  Shoulders facing forward, positioned vertically over hips.

if practicing torso side-swing, the shoulders should be moving sideways quickly away from the previous side and toward the new pushing side.

if practicing "quiet upper body" perception, then the shoulders should be quiet.

  • side view:  Knee vertically over slightly behind toe and well in front of ankle (though it's OK if knee is already over toe) -- say about 75% of the way from ankle to toe.

for Double-push "standard form", the Knee should already be vertically over the Toe.

midway configuration

  • foot-aim view:  Hip is vertically above the knee or inside the knee -- but not outside the vertical line up from the knee. [ not easy to observe ]

  • side view:  Knee vertically over Toe.

  • side view:  Ankle-knee-hip angle should exactly be the same as at Set-down -- or perhaps a little smaller, more compressed.

  • if using torso side-swing -- front view:  Shoulders over to side of pushing leg, with not much motion -- not already moving back toward the non-pushing side.

Other foot should have already set down and be aiming diagonally outward before the shoulders have moved across center to its side.

The concept of the physics is to hold back the torso side-swing move until the final phase of the leg-push.

midway motion

no "wiggly" in the motion between Set-down and Midway: see details under high-speed Normal-push.

finish

  • front view:  Pevlis and two hip joints roughly level.

  • side view:  Knee joint is extended close to straight -- knee only slightly in front of the line between hip joint and ankle joint.

see more detail below under "finish" for high-speed Normal-push.

  • side view:  Front + back of foot lift off the ground together -- pushing through the heel to the very end -- not the back of foot lifting off before the front.

  • side view:  Front of foot roughly vertically underneath the hip -- not way behind hip. The concept in "standard-form" style is to push directly out to the side. As the leg extends, the foot should come forward (relative to the knee) -- like kicking the toe into a soccer ball out in front.

recovery

  • front or rear view: the recovering foot should come close to the other leg -- perhaps for standard-form perception, could exaggerate by bringing the foot sideways behind the other leg. A helpful checkpoint could be to touch the lower leg to the back of the pushing leg -- or perhaps get the insides of the knees touching.

So then just before set-down the foot will be moving somewhat sideways outward toward its own side.

If working on Double-push, then bringing the foot sideways behind the other leg is no longer an exaggeration -- see more below under "recovery" for Double-push.

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high-speed situation for Normal-push

The "high-speed" situation means:  flat or gentle terrain, smooth pavement, not much wind.

overall

  • timing synchronization: The other foot is already set down on the ground before this leg lifts off. The Set-down of the next foot should occur before the Finish of the current foot's pushing: "overlap" timing. [ see more ] 

Key reason for this overlap timing is that the newly Set-down foot helps to support the weight of he upper body, so it's easier for the other pushing leg's hip to spend more time in a lower position -- so a larger proportion of the force from the big Extension muscles goes directly into propulsive Work. This weight-supporting role of the non-pushing foot can be emphasized by setting it down straight in the direction of the skater's overall forward motion, then pivoting it to aim diagonally (outward for Normal-push, inward for Double-push).

set down

  • front + foot-aim views: set-down with ground-contact inside the line vertically down underneath center of hip. Definitely not outside.

  • foot-aim view: set-down with knee + ankle not inside the line between hip and ground-contact. Ankle might even be slighty outside that line (i.e. in a supinated position)

  • Gentle into setting down: Motion speed and direction of the foot immediately before Set-down should be roughly the same as after Set-down. No stomping downward. No quick forward move from Recovery into Set-down.

  • front view: Hip of the leg being set down should be level with or slightly lower than the other hip which is finishing its push.

High-Speed situations: Hip of next (currently non-pushing) leg is level with or slightly lower than Hip of previous (currently pushing at Set-down) leg. (Then in "classic" normal-push (including Pivot-Aim style) after the next leg's knee extends and hip raises soon after lift-up of previous leg's foot, then the shoulders drop as the next pushing knee extends and the hips rise. But in Double-push after the lift-up of the previous leg's foot, both the shoulders and hips rise during the next leg's inward push.) - [ see discussion ]

  • front view: head + shoulders facing forward, positioned vertically over center between hips -- not already over on the pushing side. Moving definitely toward the pushing side.

  • side view:  Knee vertically over slightly behind toe and well in front of ankle (though it's OK if knee is already over toe) -- say about 75% of the way from ankle to toe.

midway configuration

  • front view or foot-aim view: hip is vertically above the knee or inside the knee -- definitely not outside the vertical line up from the knee.

  • front view: head + shoulders definitely over to side of pushing leg, with not much motion -- not already moving back toward the non-pushing side.

Other foot should have already set down and be aiming diagonally outward before the shoulders have moved across center to its side.

The concept of the physics is to hold back the torso side-swing move until the final phase of the leg-push.

  • side view:  Knee vertically over toe.

  • side view:  Ankle-knee-hip angle should exactly be the same as at Set-down -- or perhaps a little smaller, more compressed.

midway motion

No "wiggly" in the motion between Set-down and Midway:  Every joint moves at least as far sideways as the joint immediately below it.  Especially . . .

  • Knee vs Ankle -- foot-aim view:  pushing Knee joint moves at least as far sideways (relative to the ground-contact point) away from the leg-push direction as its Ankle joint moves. [ tricky to observe ]

  • Hip vs Knee -- foot-aim view:  center of pushing Hip moves at least as far sideways (relative to the ground-contact point) away from the leg-push direction as its Knee joint moves. [ tricky to observe ]

  • Shoulder vs Hip -- front view:  Pushing-side shoulder moves at least as far sideways (relative to the ground-contact point) away from the leg-push direction as the pushing Hip moves. [ not easy to observe ]

  • Often in high-speed situations the Out-sweep motion between set-down and midway is mostly in the hip-abduction and ankle-pronation moves, not so much in the medial-hip-knee-rotation move.

The typical motion for high-force situations is different.

finish

  • front view: pushing-side Hip joint is slightly higher than the non-pushing hip.

High-Speed situations: Hip of next (currently non-pushing) leg is slightly lower than Hip of previous (currently pushing at Set-down) leg. (Then in "classic" normal-push (including Pivot-Aim style) after the next leg's knee extends and hip raises soon after lift-up of previous leg's foot, then the shoulders drop as the next pushing knee extends and the hips rise. But in Double-push after the lift-up of the previous leg's foot, both the shoulders and hips rise during the next leg's inward push.) - [ see discussion ]

  • side view: knee joint is extended close to straight -- only slightly in front of the line between hip joint and ankle joint.

Note that extending the knee joint almost fully pushes the ankle + foot forward -- which feels unnatural to our natural instincts from running + walking.

Be careful of subtle ways to avoid this: like extending the ball of the foot from the ankle as a substitute for extending through the knee.

If not finding the strength+endurance to extend the knee fully, can try setting down the foot farther outside from the hip.

  • foot-aim view: Observation of the ankle joint inside the line between knee and ground-contact is typical in race videos of elite speedskaters. [ not easy to observe ]

This adds propulsive Power, by releasing gravitational potential energy into kinetic energy, and by engaging the ankle-pronation muscles to push sideways. (For most athletes, there's no need to think about this consciously; just let the brain's unconscious neuro-muscular control module take care of it).

  • side view: Observation of the back of foot lifting off the ground before front of foot is typical in race videos of elite speedskaters. (which is very different from the standard-form perception style) [ not easy to observe ]

The concept of the physics is that this adds propulsive power:  increases leg-extension range-of-motion distance and engages the ankle extension (a.k.a. plantar-flexion) muscles. (For most athletes, there's no need to think about this consciously; just let the brain's unconscious neuro-muscular control module take care of it).

  • side view: Observation of the toe finishing behind its hip is typical in race videos of elite speedskaters. (which is very different from the standard-form perception style)

The concepts of the biomechanics and physics are that:

(a) most people's biggest strongest muscles (the hip-extension muscles, e.g. gluteus) for the Extension push are designed to push significantly backwards. So to better exploit those hip-extension muscles it helps if the foot moves more backwards, less out toward side.

(b) it's not worth the trade-off of stroke-cycle Time to extract the last bit of Distance + Work out of leg-extension range-of-motion perpendicular to the aim of the glide. To achieve the maximum rate of Power over the whole stroke-cycle, it's better to transition quicker into the recovery phase, which means starting to move the foot backward. (For most athletes, there's no need to think about this consciously; just let the brain's unconscious neuro-muscular control module take care of it).

The more backward motion of the foot also fits with the final final phase of extension pushing through the ball of the foot, not the heel. The truly most effective vector of propulsive Force is perpendicular to the aim of the gliding foot, which glides at some angle away from the overall average direction of the motion of skater's body mass. And the human leg muscles are designed to push somewhat backwards. So the most effective direction of the leg-extension move is not directly exactly sideways, but also somewhat diagonally backward. Since the final final push is through the ball of the foot, it makes sense that the ball of the foot is moving somewhat backwards (so the heel must finish even farther backwards).

recovery

for simple Normal-push, recovery is not that critical (except to make it quickly enough so it doesn't delay anything else) -- front view:  Sideways somewhat toward the other leg helps some.

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high-force situation for Normal-push

The high-force situation is climbing up a steep hill, unless qualified otherwise.

No poles -- The points in this section are mostly for skating with No poles. When using poles to help push, there are some important differences for skating -- see high-force situation With poles.

overall

  • hips tend to be generally higher than for the same skater in higher-speed / lower-force situations.

Higher hip configuration geometry has a lower "gear ratio" (smaller pushing distance for the same angle of rotational motion) for the Hip-extension, Knee-extension, and Medial hip-knee rotation muscles -- which enables those muscles to sustain a higher force intensity.

Note that in a higher hip position, the Out-sweep muscles are more favored (than the Extension muscles) for getting a higher percentage of their work transmitted directly into forward propulsion thru the skate-push (because the leg-lean angle is smaller). On the other hand, for the situation of climbing up a steep hill, a key part of the task is to elevate the weight of the upper body, so some of the Extension work counts as direct propulsion work (in the upward direction), even though it's not immediately contributing to horizontal forward propulsion thru the skate-push.  That's while using No poles.

With Poles, the Extension push has another way to generate propulsive work, by vertical lifting of the weight of the upper body to build gravitational "potential energy", which can then be converted into forward propulsion work by being dropped onto the next pole-push. Although this propulsion work is not immediate or direct, it's pretty reliable and effective (at non-high speeds) -- so the Extension push tends to be very important to higher-force skating with Poles.

  • smaller range-of-motion for many muscle moves -- which allows them to focus more on the "lower gear ratio" segments of their range -- which enables them to sustain a higher force intensity.

turnover frequency: often the smaller range-of-motion leads to higher frequency (though this is not required) than for gentle or moderate terrain [ see more ]

  • timing synchronization depends on the situation:

for climbing a steep hill, there is substantial overlap of the two feet on the ground.

for starting sprints there is usually no overlap, because the force of the Extension push is so strong and quick that it sends the skater air-borne after each push.

 

set down

  • front + foot-aim views:  Set-down with ground-contact somewhat outside from vertically underneath center of hip. Definitely not inside.

  • foot-aim view:  Set-down with hip + knee + ankle + ground-contact all in line. (front view: knee somewhat outside of hip-ankle line)

Skaters with weaker medial-hip-knee-rotation muscles might need to set down with the knee somewhat inside the hip-ankle line in foot-aim view. This tends to suggest that some priority be given to training those muscles.

  • Gentle into setting down. Motion speed and direction of the foot immediately before Set-down should be roughly the same as after Set-down. No stomping downward. No quick forward move from Recovery into Set-down.

  • front view: set-down with pelvis + hips level or tilted sideways toward the leg-push which is finishing: Hip of the leg being set down should be level with or slightly higher than other hip which is finishing its push.

High-Force situations: Hip of previous (currently pushing) leg is level with or slightly lower than Hip of next (currently non-pushing at Set-down) leg - [ see discussion ]

  • front view:  Shoulders positioned vertically over hips -- not already over on the set-down side. Moving definitely toward the set-down side.

  • side view:  Knee getting close to vertically over the toe.

  • side view of ankle - knee - hip angle: knee bent much less sharply than 90 degrees.

Some of the key leg muscles and joints (including medial hip-knee rotation) can handle higher forces sustainably if the knee is not bent so much.

  • side view:  (especially on steep uphill)  The new pushing hip not forward ahead of non-pushing hip -- perhaps better if pushing hip is slightly behind.  (Exception: strong skaters on sprinting up a short hill can have pushing hip forward.) [ not easy to observe ]

midway configuration

  • foot-aim view:  Hip is vertically above the knee or inside the knee -- but not outside the vertical line up from the knee. (front view is tricky: hip sometimes appears outside the knee, because the aim of the foot is so far out toward the side) [ tricky to observe ]

  • front view:  Shoulders definitely over to side of pushing leg, with not much motion -- not already moving back toward the non-pushing side.

Other foot should have already set down and be aiming diagonally outward before the shoulders have moved across center to its side.

  • side view:  Knee vertically over toe.

midway motion

  • no "wiggly" in the motion between Set-down and Midway: see details under high-speed Normal-push.

  • Often in high-force situations the Out-sweep motion between set-down and midway is much in the medial hip-knee rotation move, some in ankle-pronation move, less in the hip-abduction move.

This is because medial hip-knee rotation muscles is in a lower "gear ratio" configuration when the hip is in a higher position, while the hip-abduction muscles are in a higher "gear ratio" configuration, and while for the ankle-pronation muscles the hip height makes no difference.

The typical motion for high-speed situations is different.

Cross-country skiing:

Elite cross-country ski racers as of 2004 typically use little or no ankle-pronation move. Likely this is related to the typical design of ski skating boots to limit or block ankle-pronation. But as of 2006 some cross-country ski racers (especially sprinters) have been seen experimenting with boots that allow freedom for the ankle-pronation move.

Cross-country skiers overall tend to use more medial hip-knee rotation than ice or inline speedskaters. Perhaps this is because: cross-country ski courses tend to include many more and steeper hills than inline or ice skating, which is where medial hip-knee rotation part of Out-sweep push is especially favored. Performance in climbing these hills is often critical for winning the race in cross-country skiing -- so cross-country ski racers tend to train these muscles well. Cross-country skiing generally has lower speeds than ice or inline speedskating, so the medial hip-knee rotation muscles tend to be useful in other situations for cross-country racers. Therefore they get into a style of skating which uses them more.

finish

  • front view: pushing-side Hip joint is slightly lower than the non-pushing hip.

High-Force situations: Hip of previous (currently pushing) leg is slightly lower than Hip of next (currently non-pushing at Set-down) leg - [ see discussion ]

  • side view:  Knee joint is extended close to straight -- only slightly in front of the line between hip joint and ankle joint.

see more detail above under "finish" for high-speed Normal-push.

key checkpoint: If the knee joint is not getting extended close to straight at the finish when climbing up a steep hill, that's a sign that the knee is bent too much and the hip is too low at set-down.

front view: sometimes in high-acceleration situations (e.g. starting sprint) both feet are in the air simultaneously -- the other foot has not landed down on the ground until after this leg lifts off.

see other typical observations above under "finish" for High-speed Normal-push.

recovery

  • key is to make it quick, so the recovery phase does not hold back turnover frequency of the big leg-extension muscles.

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high-speed situation for Double-push

The "high-speed" situation means flat or gentle terrain, smooth pavement, not much wind.

overall

  • timing synchronization: The other foot is already set down on the ground before this leg lifts off. The Set-down of the next foot should occur before the Finish of the current foot's pushing: "overlap" timing. [ see more ]

Key reason for this overlap timing is that the newly Set-down foot helps to support the weight of he upper body, so it's easier for the other pushing leg's hip to spend more time in a lower position -- so a larger proportion of the force from the big Extension muscles goes directly into propulsive Work. This weight-supporting role of the non-pushing foot can be emphasized by setting it down straight in the direction of the skater's overall forward motion, then pivoting it to aim diagonally (outward for Normal-push, inward for Double-push).

set down

  • front + foot-aim views:  Set-down with ground-contact roughly near the line vertically down underneath center of its hip -- not near the line vertically down underneath the other hip. Typically the foot is set down slightly inside its hip. (but it's good practice to "play" with getting it as far toward the outside as you can.)

in situations where higher force is called for, like Double-push up a moderate hill, set-down would be further inside to the other leg's hip.

  • foot-aim view:  Set-down with knee + ankle not outside the line between hip and ground-contact. Typically there's a rough alignment from hip through knee and ankle to ground-contact.

  • Gentle into setting down. Motion speed and direction of the foot immediately before Set-down should be roughly the same as after Set-down. No stomping downward. No quick forward move from Recovery into Set-down.

  • Pelvis at Set-down should be tilted sideways toward side of set-down, and moving toward more tilt: Hip of the leg being set down should be a little lower than other hip, and moving more lower.

  • front view:  Shoulders definitely over on the side of other leg which is finishing pushing, with not much motion -- not already moving back toward this leg's side.

Different timing than for Normal-push -- see below under "finish".

  • side view:  Knee vertically over somewhere between toe and ankle.

finish of in-push

  • front view:  Foot is vertically underneath the other leg's hip. (or even further across inside)

  • front view:  Shoulders (and arms, if using arm-swing) have started their sideways move over toward the pushing side -- quickly accelerating.

  • side view:  Toe not behind its hip. The in-push is definitely about pushing sideways, not backward. "Carving the foot forward" during the second half and finishing with the ankle vertically underneath hip (in side view) is not a bad goal.

  • side view:  Both front and back of foot still down equally close to the ground.

aim-switch

  • side view:  Heel moves back behind its hip during the aim-switch, and the knee joint flexes more. [ not easy to observe ]

The knee joint extended and the foot was driven forward during the in-push, then the knee compresses and the foot goes backward relative to hips through the Aim-switch and into the main outward push.

  • front view:  Shoulders positioned roughly vertically over hips -- not already over on the pushing side. Moving definitely toward the pushing side. (if using arm-swing, arms should be coming across the front of the hips -- not already over on the pushing side)

  • front view:  The recovering foot should ideally be in a position roughly somewhere near the vertical line of its hip as the pushing foot is going through its Aim-switch move -- and moving quickly sideways over to the pushing-side.

midway configuration

midway through the main outward push should look pretty much like high-speed Normal-push.

  • front view:  The recovering foot should have "followed through" to a position outside the pushing-side hip. (see more below under "recovery")

midway motion

no "wiggly" in the motion between Aim-switch and Midway: see details under high-speed Normal-push (substituting "Aim-switch" for "Set-down")

finish

finish of the main outward push should look pretty much like Normal-push.

except:

  • front view:  Shoulders definitely over on the side of pushing leg, with not much motion -- not already moving back toward the non-pushing side.

Different timing than for Normal-push. The concept of the physics is to hold back the torso side-swing move until the other foot sets down and starts its in-push, then do it quickly, so the maximum sideways speed is attained while the other foot is making its Aim-switch.

  • if using arm-swing -- front view:  Arms definitely over to side of pushing leg, with not much motion -- not already moving back toward the non-pushing side.

Different timing than for Normal-push. Same concept as the timing of the torso side-swing move for Double-push.

recovery

  • front view:  For larger contribution to propulsive power, the recovering foot moves sideways behind the other leg to a position outside the other leg. The recovering foot should ideally be in a position roughly somewhere near the vertical line of its hip as the pushing foot is going through its Aim-switch move -- and moving quickly sideways over to the pushing-side.

The key to adding propulsive Power is to quickly accelerate the recovering foot to achieve maximum sideways speed just as the pushing foot is making its Aim-switch move. What happens after the Aim-switch is just follow-through.

  • Then at Midway through the pushing leg's stroke, the sideways momentum of the recovering leg should have made the foot "follow through" to a position outside the pushing-side hip. (unless the skater is taking it easier for long distance, in which case the sideways motion is not as large)

But there's no benefit to continuing to move the foot slowly to get it to some outside position, because the outside position is only the result of the power of the initial quick acceleration sideways. The position without the quickness adds nothing, might even result in a loss of power due to slowing overall stroke-cycle turnover frequency.

Then what happens during the move of the foot back from the other side to its normal side and set-down isn't very important for propulsive Power -- as long as it does not slow down stroke-cycle turnover frequency.

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more . . .

see also

With Poles: key points for skating With Poles

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more . . .

?? [ to be added ]