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

see also

  

[ under construction ] 

 


 

high-force situation With Poles (Single-Poling)

This is the simplest motion technique for handling high-force situations -- critical technique for the majority of cross-country skiers to be able to enjoy skating on hilly trails. Nice thing than even if you run out of strength and can't get any glide on some of the strokes, Single-poling still works for getting to the top of the hill . . . very slowly.

Usually not the fastest for skaters with lots of skill and strength in poling, for that see V1 skate. But even fast cross-country ski skaters should still remember Single-Poling for getting over a very steep hill early in the day while saving strength to have fun for lots more easier hills afterward. Or for workouts where the objective is to avoid high stress on the muscles.

Analysis? Likely not much point in getting too deep into analysis of Single-Poling skate, since the main point of using it is to "keep it simple". Simple either because the skater has different priorities for what to focus on for technique improvement, or simple because the only time they use Single-Poling skate is when climbing up the hill seems so hard that there's little energy left over for working on technique anyway.

Skaters who are concerned about optimizing their technique for high-Force situations with poles might do better by switching to V1 skate.

overall

Usually the pole is planted distinctly after the foot is set-down on the same side, roughly after phase 1, so the pole-push assists the Extension phase 3 of the leg-push.

leg-push

video observation points and priorities for leg-push are pretty much the same as for high-force Normal-push with No poles.

except that perhaps the hips would not drop as much in phase 3, because the reactive force from the pole-push is supporting them.

video observation points and priorities for most torso and shoulder motions are the same as for high-force Normal-push with No poles.

pole-push

  • Pole-push is focused mainly in the arms.

little or no abdominal crunch, little or no dropping of upper body weight onto pole-push -- so don't expect to see much of those things in a video.

  • side view:  [A] Poling-side hand in front of pole-tip as pole tip touches ground, so the pole is definitely angled aiming backward already at the pole-plant -- not straight down into the ground.

The distance of the pole-push is usually pretty short in Single-Poling skate, so it better already be aimed in a way that allows it to immediately transmit force in a directly propulsive direction -- usually diagonally forward and toward the other side - (not just straight down into the ground in the hope that it will get into a more propulsive direction sometime later).

  • front view:  Pole aimed roughly downward and backward as pole tip touches ground -- perhaps somewhat outward -- mostly whatever feels like allows it to best assist the Extension push  by the leg.

Not much need to worry about the pole-plant absorbing sideways momentum, since the pole-plant isn't usually performed until distinctly after the foot has been set-down, so usually most of the sideways component of kinetic energy has already been transmitted thru the first phase(s) of the leg-push.

Often by the time of pole-plant the sideways motion of the upper body is getting started back toward the other side, so aiming the pole somewhat outward is helping that work, and little or none of the outward component of the arm's pushing force is going to opposing the glide of the foot, since little or none of it will be transmitted to the foot -- and the glide is close to stopping anyway regardless of the aiming of the pole-push.

The idea of the pole-push in Single-Poling skate is not mainly to "extend the glide" of the current foot further sideways -- rather it's to assist the Extension push (so there might be longer glide on the next foot). Just accept whatever glide you got from the previous push from the other side, and time this pole-push and leg-extension push to fit with that.

 

high-force situation With Poles (V1)

The leg + hip moves doing "V1" technique with Poles have some similarities to the leg moves for high-force Normal-push without poles -- but also two key differences:

  • Poling-side is very different: Especially the leg-push on the Poling-side is very different from the Normal-push with No poles.

The leg-pushes on the two sides are not symmetrical.

  • Pole-push is primary: The requirements of better using the leg muscles to apply their work to the pole-push tend to override considerations which help better apply work to the skate-push.

Although the pole-push is not an immediate direct application of the Extension work, it's a very reliable and effective use of leg Extension work for propulsion (at non-high speeds). The typical higher hip position and shorter range-of-motion for climbing up a steep hill tends to give a smaller leg-lean angle, which transmits a smaller percentage of Extension work thru the skate-push directly into propulsion (and the indirect transmission is more complicated and less effective than for applying it first toward the Pole-push).

Specific differences include:

  • the knee-extension muscles typically push twice on the recovery-side (mainly vertical lifting in phase 1, skate-push more sideways in phase 3), with a slight pause in between) -- while they push only once on the poling-side (extension in phases 2 and 3).

  • the hips rise overall through phases 1 and 2 of the Recovery-side leg-push. The hips do not rise thru phases 1 and 2 of the poling-side leg-push (perhaps drop slightly in phase 1, but mostly remain steady).

There may be a momentary hesitation in the raising of the hip in the middle of the R-side push -- but overall the hip rises during the Recovery-side leg-push. The important purpose of this is to build gravitational potential energy to be released into the pole-push.

Overlap of the feet on the ground is important for the lifting of the weight of the upper body on the Recovery-side -- so at first the two legs work together to start raising the mass of the hips and upper body upward (at the end of phase 3 of the Poling-side and the start of phase 1 of the Recovery-side). Also the shoulders may start rising before set-down of the Recovery-side leg, so there is usually already some upward kinetic energy of the upper body, before the recovery-side leg starts its hard solo work of lifting the weight of the upper body.

  • the hips drop at the end phase 3 on the Recovery-side. The hips start rising at the end of phase 3 on the Poling-side.

  • the P-side leg-push has more horizontal sideways distance than the R-side leg-push.

  • in phase 1 after set-down of the Recovery-side leg, the leg-push has a definite upward component, especially from a knee-extension move.

There is also a substantial Out-sweep move starting immediately on set-down, especially by the medial-hip-knee-rotation move.

  • phase 2 of the recovery-side leg-push might possibly include a dropping of the hips (with a knee-flexion move), which puts more downward kinetic energy into the start of the pole-push.

Then the knee-extension move starts again in phase 3 Extension, but its sideways distance is shorter than on the poling-side, because the pushing hip is higher than it will be on the poling-side.

  • Initiating an abdominal crunch move in phase 3 of the Recovery-side (before the pole-plant) reduces the force needed to complete the Recovery-side Extension move

It also tends to reduces gliding friction, at a moment when the Recovery-side glide is in danger of stalling out.

There is little or no loss in propulsive work from this abdominal crunch move, because it converts potential energy to downward kinetic energy (and adds downward kinetic energy of its own). At the pole-plant the kinetic energy is transmitted thru the arms into the poles, which then convert it into forward-propulsion work at the ground.

No poles? An early dropping of the shoulders might also help in some similar way when climbing up a steep hill with No poles (though there can be no net reduction in average gliding friction without using poles).

There's also a key difference in the sideways motion of the upper body:

  • sideways motion of shoulders and torso is asymmetrical: More distance sideways (shoulders relative to hips) toward the Poling-side, less distance sideways toward the Recovery-side.

specifics

In the points about leg moves here below, the focus is on how they are different from the leg moves of the High-force situation for Normal-push without poles -- but many of the points from "High-force without poles" still apply, so check that section too. The points here below also are about how poling and upper body moves should coordinate with the leg moves.

overall

  • [B+] overlap timing of both feet on the ground, since . . .

(a) the feet can work together to accelerate the mass of the upper body upward, which reduces peak-force intensity stress on the Recovery-side Extension muscles, so they can sustainable handle a larger vertical range-of-motion. By quickly getting this vertical lifting up to speed, it tends to reduce the amount of precious stroke-cycle time, which can enable either a higher turnover frequency or a larger vertical range-of-motion to be sustained.

(b) gliding friction: Vertical force to the ground is higher in the initial upward acceleration of upper-body weight (higher than just normal support of body weight) -- so spreading this higher force across both feet tends to reduce the downward force thru each foot, and thus avoid this increased gliding friction.

  • [A] pole-plant timing is before set-down of the poling-side foot -- see more below.

  • [A] many pole-push moves start before pole-plant -- see more below.

planting of pole tips

  • [A] pole-plant timing is before set-down of the poling-side foot.  This is so all the downward kinetic energy is transmitted thru the pole-push, not the skate-push, since . . .

(a) at this point in the stroke-cycle the pole-push converts a much higher percentage of vertical force and energy directly into forward propulsion work than the skate-push.

(b) gliding friction: applying extra downward force to the skate-push would greatly increase gliding friction (over the friction from just normal support of body weight).

Typically the pole-tips touch the ground only an instant (.03-.04 second) before the Poling-side foot sets down.

  • side view:  [A] many pole-push moves start before pole-plant.

Hips start dropping before the pole-plant (but do not continue dropping much afterward). The gravitational kinetic energy of the elevated weight of the upper body is converted into (a) kinetic energy adding work to the Recovery-side skate-push; and (b) downward kinetic energy which is transmitted thru the abdominal crunch + shoulder + arm muscles into the pole-push.

Head + shoulders are already moving downward before pole-plant and set-down.

The upper abdominal muscles are already "crunching down" before the pole-plant. Then statically transmit the downward kinetic energy immediately following pole-plant. Then continue active positive motion "crunching" down on the poles.

Starting the abdominal crunch move before the pole-plant has benefits, see above.

Shoulders are positioned down + forward at set-down, and moving further down + forward.

Start the arm-push move (and abdominal crunch move) before the pole-plant, for quicker and more "rigid" transmission of vertical kinetic energy into the poles.

The main role of the arms is to statically transmit the energy from the upper body, not to add positive work of their own. Any active positive pushing by the arms later in the stroke-cycle is at most just an after-thought.

  • both pole tips are planted roughly at the same time.

  • the more elite the competitive level, the more aggressive and explosive is the pole-plant move.

Training the arm + shoulder muscles to quickly and "rigidly" transmit the high impact force is the "price of admission" to higher levels of competitive cross-country ski racing. (Trying out the aggression or explosiveness in the pole-plant move before a careful progression of appropriate training is asking for injury.)

Training the abdominal crunch muscles to deliver explosive "crunch" force and transmit force from the dropping hips -- and training the Back-extension muscles to quickly recover the weight of the shoulders + upper torso + head up high again --  is the "price of admission" to higher levels of competitive cross-country ski racing. (Too much or too aggressive vertical shoulder motion before a careful progression of training of the Back-extension muscles is asking for injury.)

There's a place for "smoothness" and "relaxed muscles" in elite racing technique, but it's not in the pole-plant move.

  • front view:  [A] Poling-side hand not inside the Poling-side pole-tip (on the ground).

Poling-side pole-push is initially aimed down toward the Recovery-side or down straight backwards, not initially aimed down at all toward the Poling-side.

Because if the pole-push is initially aimed partly toward the Poling-side, then a portion of the sideways kinetic energy from the torso and shoulders will be transmitted into the pole instead of into the foot. But the skating foot can convert sideways kinetic energy into forward-propulsion work fairly effectively, and as a simple side-effect of its normal skate-push role, with no distraction. The pole cannot make this conversion very effectively, and anyway it's already got a different important role to focus on: converting downward force and energy into forward-propulsion work. So any sideways energy that goes into the pole is wasted and/or distracting.

Key: It is not OK if the Poling-side hand moves outside the P-side pole-tip only later in the P-side push, after the hand started on the inside at Set-down. The starting configuration is critical. Therefore . . .

Make sure to move the Poling-side hand outside farther before planting pole or setting down foot, and make sure to plant the Poling-side pole tip close beside the Poling-side foot.

  • side view: [A] Poling-side hand in front of pole-tip, so the pole is definitely angled aiming backward already at the pole-plant.

Key: It is not OK if the pole-tip is definitely aiming backward only after the pole-plant.

The downward kinetic energy from the falling weight of the upper body must be immediately converted into forward-propulsion work at the moment of the pole-plant. If the pole-tip is aimed mainly vertically instead of backward at the pole-plant, this energy just goes into pounding the pole-tip deeper into the ground and bending the pole shaft -- it's forever lost for propulsive work.

The "optimal" pole angle range for converting vertical force to forward force is for use thru the brief time of transmission of downward kinetic energy at and immediately after the moment of set-down. It is not "saved" for active pushing by the arm or shoulder or abdominal crunch muscles later afterward.

The primary source of power for poling is from the Leg-extension and Back-extension muscles elevating the weight of the upper body before the pole-plant and/or pole-push moves. There's simply more aerobically-trained muscle mass available in those muscles than the other muscles "closer" to the poles. So their resulting downward kinetic energy gets the optimal pole angles for converting into forward propulsion work.

Other muscle moves active during the pole-push afterward get to use the angles and whatever ground-contact distance and time that are "left over" for delivering and converting their work into forward propulsion. Though actually some of that poling muscular work performed later goes partly into starting to elevate and accelerate the mass of the upper body upward just before the start of the next Recovery-side push.

set-down of Poling-side foot

  • front view:  [A] Shoulders already somewhat over (but not all the way) on the Poling side, and still moving even further over on the Poling side.

There's two ways to get this wrong: (1) shoulders already over on the Poling-side and already slowed down and (nearly) stopped; and (2) sideways torso-shoulder moves too symmetrical, not enough commitment to the Poling-side.

A possible mental image to help this: Think about trying to set down the Poling-side foot further inside underneath, with the hips and upper body "falling over" it sideways toward the outside.

  • front view:  two Hip joints at roughly the same vertical level -- though arguments can be made for why they should be tilted slightly to one side or the other.

Some elite cross-country ski racers have the recovery-side hip slightly higher than the poling-side hip.

  • side view:  New pushing hip not forward ahead of non-pushing hip -- usually easier if the new pushing hip is somewhat behind.  [ not easy to observe ]

Exception: Strong skaters sprinting up a short hill can have the pushing hip forward.

relative motions thru midway of Poling-side leg-push

  • [A] no "wiggly" in the motion between Set-down and Midway: see details under high-speed Normal-push. Except perhaps the Shoulder versus Hip constraint might not hold because of focus on the Pole-push.

As the hip drops in phase 1 to add work to the pole-push, it can be tempting to allow the knee to collapse inward. Fight to prevent this -- if anything try to move the knee outward in phase 1 (using the hip-abduction muscles). Often it's difficult to achieve any visible outward motion of the knee from the hip, but it's still important to prevent the knee from moving inward as the hip drops. The medial hip-knee rotation move adds propulsive work not by moving the knee inward under the hip, but by driving the ankle outward from under the knee.

  • [A] Shoulders are further over on the poling-side than they were are set-down.

Partly because the initial phase of the pole-push is aimed partly toward the poling-side -- not straight in the direction of the skater's overall forward motion. (Then later in the stoke-cycle the pole-push is aimed more toward the direction of overall forward motion.)

  • [A] Key timing point:  The torso + shoulders keep moving toward the Poling-side until the Poling-side hand pushes down by the Poling-side hip.

A frequent timing mistake is to stop the sideways motion of torso + shoulders toward the Poling-side soon after set-down (perhaps with the idea of helping to drive the Recovery-side pole). But the better strategy is to continue "crunching" down over the Poling-side pole, and hold back on turning away. The torso + shoulders start moving away toward the Recovery-side only in the final phase of the leg-push and pole-push -- and then they move quickly.

Related timing point: The shoulders do not start rising up until after the Poling-side hand pushes down by the Poling-side hip.

midway configuration in Poling-side leg-push

  • [A] front view:  Shoulders definitely way over on the Poling-side (with their side motion finally stopped) -- not already moving back toward the Recovery-side.

  • [A] front view:  Hips are not any higher than at set-down.

but not much lower either, and perhaps the hips are not at all lower than at set-down. When skating with No poles, you might expect the hip to rise a little after set-down, then start to fall. On the other hand, With Poles, the weight of the upper body is supported thru the Poling-side leg-push by the reactive upward force from pushing on the poles (as well as some reactive upward force component from the skate-push) -- so it's difficult for the hips to fall much during the P-side push. But it is unhelpful for the hips to rise before the later part of phase 3, because that would absorb propulsive work from the continuing pole-push, and also (after phase 1) from the leg's skate-push.

  • [B+] foot-aim view: Foot is further outward relative to the knee than it was at Set-down. [ not always easy to see ]

This is a sign of medial hip-knee rotation muscles contributing propulsive work thru the skate-push.

  • [A] front view:  Poling-side hand is not inside from vertically above the pole tip.

set-down of Recovery-side foot

  • [A] front view:  Other poling-side foot is still on the ground, so the two legs can work together in raising the hips.

  • [A] front or side view:  Hips are already moving upward some before set-down(and perhaps the shoulders a little, also).

  • [A] front view:  Shoulders positioned vertically over hips or slightly over toward Recovery side -- but not already clearly over on the Recovery side. (but Moving quickly toward the Recovery side).

If the shoulders are already clearly over on the Recovery-side, that's a sign of the frequent error of turning away from the Poling-side too early.

  • front view: At first tend to see more motion of the mass of the torso and shoulders sideways across away from the Poling-side leg, then soon emphasis of the motion shifts to recovering the shoulders upward.

Perhaps the point is to initially make it easier for the Poling-side leg acting solo to start accelerating the hips upward -- hold adding the burden of additional rise of shoulders until the two legs can work together.

  • front view:  Pelvis + hips tilted slightly toward Recovery-side, with the Recovery-side hip lower. (to sort of "lead" the tipping and swinging of the torso + shoulders over to the Poling-side).

  • side view:  Recovery-side hip not forward ahead of Poling-side hip -- usually better if Recovery-side hip is somewhat behind.  (Exception: strong skaters on sprinting up a short hill can have pushing hip forward.) [ not easy to observe ]

relative motions thru midway of Recovery-side leg-push

  • [A] hips definitely rising above their vertical position at set-down, and knee joint is more extended than at set-down.

  • [A] shoulders definitely rising above their vertical position at set-down.

  • [B] not much sideways motion of shoulders.

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

midway configuration in Recovery-side leg-push

  • [A] side + front views:  Shoulders getting high above hips, with spine straightening up.

  • [A] front view:  Shoulders definitely over on the Recovery-side (with their side motion finally stopped) -- not already moving back toward the Poling-side.

  • Key timing point:  Torso + shoulders "tip" over toward the Recovery-side, and then hold there until the final phase of the Recovery-side leg-push. Then they make a quick move across and down onto the Poling side.

But what matters is not how extreme the sideways position is -- but rather the quickness of the side-to-side motion of torso + shoulders, and preparing for that quickness by first holding it back.

Better to have a less extreme sideways tipping position, and higher overall stroke-cycle turnover frequency.

finish of Recovery-side leg-push

  • [A] side view:  Recovery-side leg goes pretty near to full extension (at some time before the finish)

Key: If the leg does not go to full extension, that's a sign that the hips were allowed to drop too low on the Poling-side ("butt down in the bucket")

Or it could be a sign that hip-raising "tricks" were not used to avoid making a "solo single-leg press". The key tricks are: (a) starting the raising before the end of the Poling-side push; (b) overlapping feet on the ground to work together; (c) early abdominal crunch move to drop the shoulders and apply reactive upward force to the mass around hips and butt.

  • [A] side or front view:  Abdominal crunch move starts during Recovery-side phase 3, before the pole-plant -- see more detail.

  • [A] side or front view:  Hips are dropping down before the pole-plant and before the set-down of Poling-side foot.

This is the typical falling of the hips seen in phase 3 of Normal-push skating with No poles. The key difference is that the energy of the falling upper body while skating with No poles falls onto the other leg, while in this technique for skating With Poles, it falls onto the poles.

Note that this motion of the hips in later phase 3 on the Recovery-side is opposite to their motion in later phase 3 on the Poling-side.

  • [A] Shoulders are moving quickly toward the Poling-side.

recovery of leg

see under "recovery" for high-force Normal-push without poles.

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non-high-force Normal-push With Poles (V2)

  

[ under construction ] 

 

overall

  • [B+] overlap timing of both feet on the ground, since . . .

(a) setting down the next foot early can support the hip of the previous push in a lower position for a longer time, enabling a higher percentage of the previous Extension push to be directly transmitted into propulsive work for a longer time.

(b) the feet can work together to accelerate the mass of the upper body upward, which reduces peak-force intensity stress on the Recovery-side Extension muscles, so they can sustainable handle a larger vertical range-of-motion. By quickly getting this vertical lifting up to speed, it tends to reduce the amount of precious stroke-cycle time, which can enable either a higher turnover frequency or a larger vertical range-of-motion to be sustained.

(c) gliding friction: Vertical force to the ground is higher in the initial upward acceleration of upper-body weight (higher than just normal support of body weight) -- so spreading this higher force across both feet tends to reduce the downward force thru each foot, and thus avoid this increased gliding friction.

set-down

  • [B] side view:  hip of new pushing leg is already rising.

  • [B] front view:  Shoulders either above hips or already somewhat over (but not all the way) on this new pushing side -- and still moving even further over toward this side.

Typical shortfalls are: (a) shoulders already over on this new pushing side and already slowed down and (nearly) stopped; or (b) almost no sideways torso-shoulder motion at all, upper body too quiet.

  • ?? front view:  two Hip joints at roughly the same vertical level -- though arguments can be made for why they should be tilted slightly to one side or the other.

  • ?? side view:  New pushing hip not forward ahead of non-pushing hip -- usually easier if the new pushing hip is somewhat behind.  [ not easy to observe ]

?? Exception: Strong skaters sprinting up a short hill can have the pushing hip forward.

before pole-plant

  • [A} Shoulders rise after set-down, then start dropping.

  • [A] Hips rise after set-down

usually rise up to pretty near full extension, but some skaters might prefer an overall hip position tending not quite so high, espeically for higher-speed situations. Overall higher hip position is not as important for the non-high-force situations as it is for the higher-force situations.

  • [A} Hips start dropping before the planting of the the pole tips.

Hips start dropping before the pole-plant. The gravitational kinetic energy of the elevated weight of the upper body is converted into (a) kinetic energy adding work to the skate-push; and (b) downward kinetic energy which is transmitted thru the abdominal crunch + shoulder + arm muscles into the pole-push.

  • [A] no "wiggly" in the motion between Set-down and Midway: see details under high-speed Normal-push. Except perhaps the Shoulder versus Hip constraint might not hold because of focus on the Pole-push.

As the hip drops in phase 1 to add work to the pole-push, it can be tempting to allow the knee to collapse inward. Fight to prevent this -- if anything try to move the knee outward in phase 1 (using the hip-abduction muscles). Often it's difficult to achieve any visible outward motion of the knee from the hip, but it's still important to prevent the knee from moving inward as the hip drops. The medial hip-knee rotation move adds propulsive work not by moving the knee inward under the hip, but by driving the ankle outward from under the knee.

  • [B+] foot-aim view: Foot is further outward relative to the knee than it was at Set-down. [ not always easy to see ]

This is a sign of medial hip-knee rotation muscles contributing propulsive work thru the skate-push.

  • [A] side view:  many pole-push moves start before pole-plant.

Head + shoulders are already moving downward before pole-plant and set-down.

The upper abdominal muscles are already "crunching down" before the pole-plant. Then statically transmit the downward kinetic energy immediately following pole-plant. Then continue active positive motion "crunching" down on the poles.

Starting the abdominal crunch move before the pole-plant has benefits, see above.

Shoulders are positioned down + forward at set-down, and moving further down + forward.

Start the arm-push move (and abdominal crunch move) before the pole-plant, for quicker and more "rigid" transmission of vertical kinetic energy into the poles.

The main role of the arms is to statically transmit the energy from the upper body, not to add positive work of their own. Any active positive pushing by the arms later in the stroke-cycle is at most just an after-thought.

planting of pole tips

  • the more elite the competitive level, the more aggressive and explosive is the pole-plant move.

Training the arm + shoulder muscles to quickly and "rigidly" transmit the high impact force is the "price of admission" to higher levels of competitive cross-country ski racing. (Trying out the aggression or explosiveness in the pole-plant move before a careful progression of appropriate training is asking for injury.)

Training the abdominal crunch muscles to deliver explosive "crunch" force and transmit force from the dropping hips -- and training the Back-extension muscles to quickly recover the weight of the shoulders + upper torso + head up high again --  is the "price of admission" to higher levels of competitive cross-country ski racing. (Too much or too aggressive vertical shoulder motion before a careful progression of training of the Back-extension muscles is asking for injury.)

There's a place for "smoothness" and "relaxed muscles" in elite racing technique, but it's not in the pole-plant move.

  • [A] side view: Poling-side hand in front of pole-tip, so the pole is definitely angled aiming backward already at the pole-plant.

Key: It is not OK if the pole-tip is definitely aiming backward only after the pole-plant.

The downward kinetic energy from the falling weight of the upper body must be immediately converted into forward-propulsion work at the moment of the pole-plant. If the pole-tip is aimed mainly vertically instead of backward at the pole-plant, this energy just goes into pounding the pole-tip deeper into the ground and bending the pole shaft -- it's forever lost for propulsive work.

The "optimal" pole angle range for converting vertical force to forward force is for use thru the brief time of transmission of downward kinetic energy at and immediately after the moment of set-down. It is not "saved" for active pushing by the arm or shoulder or abdominal crunch muscles later afterward.

The primary source of power for poling is from the Leg-extension and Back-extension muscles elevating the weight of the upper body before the pole-plant and/or pole-push moves. There's simply more aerobically-trained muscle mass available in those muscles than the other muscles "closer" to the poles. So their resulting downward kinetic energy gets the optimal pole angles for converting into forward propulsion work.

Other muscle moves active during the pole-push afterward get to use the angles and whatever ground-contact distance and time that are "left over" for delivering and converting their work into forward propulsion. Though actually some of that poling muscular work performed later goes partly into starting to elevate and accelerate the mass of the upper body upward just before the start of the next Recovery-side push.

  • front view: pole-tips might be aimed exactly downward and backward, or might be aimed partly toward the outside

Whether the poles are aiming directly backward or partly toward the outside doesn't make much difference, since the sideways energy was converted into forward propulsion work well before the pole-plant.

While the effective forward-backward distance of the push tends to be a little shorter if the poles are aimed a little outward, this can be compensated for just by using slightly longer poles.

Anyway the optimal forward-backward distance and/or angular range of the pole-push is tricky to determine, since there are trade-offs in the biomechanics of range-of-motion versus force-intensity versus turnover frequency.

after pole-plant

  • Hips might continue to drop a little further, or might hold steady at the same vertical level.

The hips do not rise, because that would tend to soften the pole-push.

  • [A] Shoulders continue to drop, with a continuing "abdominal crunch" move down onto the poles.

 

finish

  • [A] other foot sets down early, to support the pushing hip in a lower position

which enables a higher percentage of the Extension push in phase 3 to be directly transmitted into forward propulsion work thru the skate-push.

  • [B+] hips are already starting to move upward.

which is different from what is usually seen at the Finish of a push with No poles.

  • [B+] torso + shoulders are moving toward the other side (relative to the hips).

[ more to be added ]

 

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more . . .

?? [ to be added ]