what's here

more comparisons

see also


Introduction

 

see Introduction on Leg muscle comparison page

?? [ more to be added ]

 

summary of results

Normal skating can uses 50% more muscle moves then running, 2 times as many as bicycling, 3 times as many as walking.

Double-push stroking can use more than 2 times as many as any of those other non-skating motions (ones which do not use ski poles).

Considering that the complexity of the interaction effects between different factors is typically proportional to the square of the count of factors, improving technique for higher speed in skating might be 2 or 3 or 4 times as complicated as running or seated bicycling.

count of muscle moves

number of distinct muscle moves available to contribute forward-propulsion work:

motion technique:
major
moves
simple
min
articu-
lations
range
articu
de-sync
points
skating normal-push 5-6 1-2 16.5 13-20 1.5 (or 2)
skating double-push 8-10 2-3 25    19-32 3
walking   1-2+ 1.5   5.5 4-7 0
running 4-6 3-4 11.5 10-13 2
cycling seated 3 1 4 4 1
cycling standing 7-8 1 10 9-12 1

in list form:

  • "simple" normal-push skating:  func= 5-6,  artic= 16.5  (range 13-20), desync 1.5 (or 2)

  • double-push skating: func= 8-10,  artic= 25  (range 19-32), desync= 3 (or 3.5)

  • walking:  func= 1-2+,  artic= 5.5  (range 4-7),  desync= 0

  • running:  func= 5-6,  artic= 11.5  (range 10-13),  desync= 2 (or 2.5)

  • cycling seated:  func= 3,  artic= 4, desync= 1

  • cycling standing:  func= 7-8,  artic= 9-12, desync= 1

See details below under Compare complexity of other Motions.

cross-country skiing

motion technique:
major
moves
simple
min
articu-
lations
range
articu
de-sync
points
skating no poles 5-6 1-2 15  12-18 1.5 (or 2)
skating V1 9 2-4 20  18-22 2.5 (or 3)
skating V2 8 2-4 20  19-21
clas striding no poles 4-5 3-4 10.5 9-12
clas striding with Poles 7 4-5 17  16-18
pure double-poling 6 1-2 12  12 1.5

in list form:

  • skating on (non-short) skis with no poling:  func= 5-6,  artic= 15  (range 12-18), desync 1.5 (or 2)

  • classic striding on skis with no poling:  func= 4-5,  artic= 10.5  (range 9-12), desync= 2 (or 2.5)

  • V1 skate:  func= 9,  artic= 20  (range 18-22), desync 2.5 (or 3)

  • V2 skate:  func= 8,  artic= 20  (range 19-21), desync= 2

  • Classic striding with poling:  func= 7,  artic= 17  (range 16-18), desync= 2

  • pure Double-Poling:  func= 6,  artic= 12, desync= 1.5

See details on Compare ski-skating with other skiing motion techniques page.

see also

Complexity of moves for Skating

Upper Body: In addition to the Leg + Hip moves of skating, there are more muscles with distinct functional roles in the Upper Body which available to add forward-propulsion work in skating (without using ski poles to help push):

Upper Body moves for "simple" Normal-push stroking

These are the upper body moves available to add net positive propulsive work for "simple" straight-angle continuous ground-contact normal-push stroking.

Variations on normal-push stroking such as "switch-aim-angle" and "hop" are covered below under double-push stroking.

major move "functions" (Upper Body)

  • leg-kick-backward : moves the ball of the foot backward relative to the hip. Can use these moves: hip-extension, knee-flexion, ankle-extension.

a portion of another move function has slight benefit:

  • leg-kick-backward : moves the ball of the foot backward relative to the hip. Can use these moves: hip-extension, knee-flexion, ankle-extension.

sub-moves + "articulations" (Upper Body)

upper body side-swing

(two-way side swing, with timing for reactive side-force)

  • abdomen-torso side-swing

  • chest-shoulder side-swing

  • arm side-swing inward from shoulder

  • arm side-swing outward from shoulder

  • (small contribution)  forearm side-swing inward from elbow

  • (small contribution)  forearm side-swing outward from elbow

upper body up-down

with timing for reactive down-force: The idea is to start the torso moving upward during Phase 3, downward during phase 1 of the push by the next leg, upward during phase 3 of that leg, etc.

  • (small contribution)  lower-back-extension

  • (small contribution)  upper-back-extension

Complexity of Entire Body moves for Normal-push skating

de-synchronization of timing among moves

My analysis of the stroke-cycle shows these points where the amount of propulsive work is impacted by the accuracy of de-synchronization:

  • 0.5 for Starting the phase 1 leg-sweep-outward move early, perhaps overlapping with phase 3 of the previous push by the other leg.  Then starting the leg-radial-press move later, but with some overlap between the two different kinds of pushing motions by the same leg.

  • 1 for Delaying start of the arm-side-swing and spine-torso-side-swing moves until later during the leg's main push

. . . so that their highest sideways speed will be attained as weight is transferred from one foot to the other, and their deceleration and stopping will occur during the main push of the next leg on the other side. The temptation is synchronize the start of the side-swing moves with the start of the main leg-push move -- but then the deceleration occurs mostly while the weight is on the same foot whose push is still aimed toward the same side -- so the resulting reactive side-force yields negative work which roughly cancels the earlier positive propulsive work.

  • perhaps 0.5 for the direction of the rotation of the torso and shoulders (spine-torso-side-swing move) moving opposite from the rotation of the pelvis and hips (pelvis-twist move).

Actually this is not de-synchronization of timing, but the feeling of moving linked body parts in opposite directions is surely is strange for most skaters -- and the concept is counter-intuitive for many coaches (as of 2006). There is no de-synchronization of timing, because for maximum propulsive work, the timing of the starting and stopping of the pelvis-twist move can be simultaneous with the starting and stopping of the main leg-push.

It might be thought that there is a slight propulsion advantage to delaying the start of the sideways component of the leg-recovery move, so it is not immediately on the finish of the main leg-push, then making the move quicker. But I think a similar propulsive benefit can come from starting it immediately, then moving it further over to the other side behind the other leg.

calculate complexity

Results from Leg+Hip complexity:

  • "simple" normal-push skating -- Leg+Hip:  func= 3,  artic= 10.5  (range 9-12)

  • skating on (non-short) skis with no poling -- Leg+Hip: func= 3,  artic= 9  (range 8-10)

Upper body moves:

  • add  func= 2,  artic= 5  (range 4-6)  for upper body side-swing

  • add  func= 0-1,  artic= 1  (range 0-2)  for upper body up-down

Total propulsive moves available from entire body:

  • "simple" normal-push skating:  func= 5-6,  artic= 16.5  (range 13-20), desync 1.5 (or 2)

  • skating on (non-short) skis with no poling:  func= 5-6,  artic= 15  (range 12-18), desync 1.5 (or 2)

Upper Body moves for Double-push stroking

These are the upper body moves available to add net positive propulsive work for double-push stroking.

Many of these moves are also available for variations on normal-push stroking such as "switch-aim-angle" and "hop".

major move "functions"

a portion of another move function has slight benefit:

  • leg-kick-backward : moves the ball of the foot backward relative to the hip. Can use these moves: hip-extension, knee-flexion, ankle-extension.

sub-moves + "articulations"

upper body side-swing

(two-way side swing, with timing for reactive side-force)

  • abdomen-torso side-swing

  • chest-shoulder side-swing

  • arm side-swing inward from shoulder

  • arm side-swing outward from shoulder

  • (small contribution)  forearm side-swing inward from elbow

  • (small contribution)  forearm side-swing outward from elbow

upper body up-down

(with timing for reactive down-force)

  • (small contribution)  upper-back-extension

  • (small contribution)  neck-extension

I'm only going to give each of these 0.25 contribution to the muscle move count, since I'm not sure they can effectively be coordinated in a way to make much contribution in way that doesn't get in the way of other propulsive moves.

upper body forward-backward

(with timing for reactive backward-force)

arm-swing forward-backward

  • shoulder-flexion (arm swing forward from shoulder)

  • (small contribution)  elbow-flexion (forearm swing forward from elbow)

  • (small contribution)  scapula-abduction -- shoulder reach forward relative to spine

Complexity of Entire Body moves for Double-push skating

de-synchronization of timing among moves

My analysis of the stroke-cycle shows these points where the amount of propulsive work is impacted by the accuracy of de-synchronization:

  • 0.5 for Starting the phase ip1 leg-sweep-inward move early, perhaps overlapping with phase 3 of the previous push by the other leg.  Then starting the leg-radial-press move later, but with some overlap between the two different kinds of pushing motions by the same leg.

  • 1 for delaying start of the second half of the arm-side-swing and spine-torso-side-swing moves until after the current leg's main-push finishes.

. . . so that their deceleration and stopping will occur during the main push (instead of the in-push) of the next leg on the other side. The "second half" of the range-of-motion of these body parts is the segment from crossing the center to reaching their farthest position out on the other side (of the next leg).

The temptation is synchronize the start of the side-swing moves with the set-down of the next leg -- but then the deceleration and stopping occurs mostly during the in-push while pushing of the next foot is aimed toward the same side as the starting and acceleration -- so the resulting reactive side-force yields negative work which roughly cancels the earlier positive propulsive work.

  • 0.5 for delaying the start of the first half of the arm-side-swing and spine-torso-side-swing moves until after the current leg's main-push finishes.

. . . so that they will attain a higher maximum speed at the moment of the Aim-switch between the in-push and the main-push. The "first half" of the range-of-motion of these body parts is the segment from their farthest position out on this side (of the currently pushing leg) into the crossing of the center. (Note that this holding back the start until after the main-push, is a more radical delay than is most effective for propulsive work in normal-push stroking.)

Even expert skaters who know to delay the second half of these moves often cannot resist the temptation of allowing these body parts to "drift" in toward the center while the main-push is still going -- thus losing much of the reactive side-force benefit of the "first half" of these moves -- because what determines the net positive amount of reactive side-force work is not the distance of the range-of-motion, but the sideways speed attained at the moment of weight-transfer between the foot pushing toward one side to the foot pushing toward the other side.

  • 0.5 (or perhaps 1) for the direction of the rotation of the torso and shoulders (spine-torso-side-swing move) moving opposite from the rotation of the pelvis and hips (pelvis-twist move) -- and the timing

Actually this is more of a de-synchronization of direction than it is of timing, because the feeling of moving linked body parts in opposite directions is surely is strange for most skaters -- and the concept is counter-intuitive for many coaches (as of 2006). (Unlike for normal-push) there is also some de-synchronization of timing, because the duration of the pelvis-twist move can be "spread" over both the in-push and main-push moves, so is it not simultaneous with any other single move.

  • 0.5 for delaying the start of the forward component of set-down of the recovering leg through the air, then making the move quicker.

Delaying the start permits the forward speed at set-down to be larger. In order to gain net positive benefit from reactive forward-backward force, the next leg must still be moving forward with significant speed at the instant of set-down, so that a substantial proportion of its deceleration takes place after body weight has been transferred onto it (and off from the other foot). Therefore the next foot must be set-down near or slightly behind the forward-backward position of the currently pushing foot, not out in front -- so it has room for deceleration.

So there is not much distance available for the acceleration phase of this "recovering-leg kick forward" move. And the muscles which drive this move are big and strong -- so if they apply their full (repeatable) force immediately, the foot would reach the set-down location too early, before the other leg had finished its main-push. But if they apply less than their full force, then foot does not attain as high a forward speed -- and forward speed of the leg at the moment of set-down is what determines the net positive amount of reactive forward-backward-force work.

Note that in double-push stroking (but not normal-push) it is OK to allow early "drift" of the sideways component of the set-down move, inward toward the center, because the work from this sideways component of Set-down phase ip0 (but not of Recovery phase R) is necessarily self-cancelling for double-push (but not normal-push).

which yields a total of 2.5 (or perhaps 3) timing de-synchronization points.

calculate entire-body complexity

Results from Leg+Hip complexity:

  • double-push skating -- Leg+Hip: func= 5-6,  artic= 17.5  (range 14-21), desync= 1

Upper body moves:

  • add  func= 2,  artic= 5  (range 4-6)  for upper body side-swing

  • add  func= 0-1,  artic= 0.5  (range 0-2)  for upper body up-down

  • add  func= 1,  artic= 2  (range 1-3)  for upper body forward-backward

Total propulsive moves available from entire body:

  • double-push skating: func= 8-10,  artic= 25  (range 19-32), desync= 3 (or 3.5)

Compare complexity of other motions

Walking

Walking with continuous ground contact has no upper body moves that add net positive propulsive work. This is because the work from the acceleration and from the deceleration components are equal and opposite -- and for moves above the hips, both parts are equally transmitted to the ground. So any upper body move in walking is self-cancelling.

de-synchronization of timing among moves

All propulsive moves are simply sequential. Timing of leg-recovery or arm-swing relative to main leg-push is irrelevant to propulsive work (but might make a difference for balance).

No significant timing de-synchronization points.

calculate entire-body complexity

Results from Leg+Hip complexity:

  • walking -- Leg+Hip:  func= 1-2+,  artic= 5.5  (range 4-7)

Total propulsive moves available from entire body:

  • walking:  func= 1-2+,  artic= 5.5  (range 4-7),  desync= 0

Running

Running has some upper body moves that can add net positive propulsive work.

How come these moves work for running but not for walking? The key difference is that in the running stroke-cycle there is a phase where both feet are off the ground at the same time. The "trick" is to time the acceleration / deceleration segments of an upper body move so that the positive forward-backward reactive force comes while some foot is on the ground and the negative reactive force comes while both feet are up in the air. So the positive is transmitted into forward-propulsion, but the negative is not.

see more detail on phases and timing coordination in running

Possibly there could be a positive contribution from up-down reactive force, but the obvious upper body up-down moves have negative impacts on forward-backward reactive force.

major move "functions"

a portion of another move function has slight benefit:

sub-moves + "articulations"

upper body forward-backward

(with timing for reactive backward-force)

  • arm swing forward from shoulder

  • forearm swing forward from elbow

  • scapula-abduction -- shoulder reach forward relative to spine

  • (small contribution) upper-abdomen-chest-flexion

  • (small contribution) neck-flexion

de-synchronization of timing among moves

I have not surveyed the latest experimental observations analysis of the subtleties of the running stroke-cycle, but here's my attempt to provide a numerical estimate of the complexity of its timing coordination, for the sake of comparison.

My analysis of the stroke-cycle shows these points where the amount of propulsive work is impacted by the accuracy of de-synchronization:

  • 1 for start of leg-recovery should be delayed until after the other foot sets down onto the ground. For maximum work, hold the leg extended out behind after it lifts off, while both feet are up in the air. Don't let it start drifting down and forward too early.

  • perhaps 0.5 for start of arm-swing-forward could be delayed until after the start of leg-recovery move, then bring the arm forward quicker than the leg.

The easier timing to learn is to synchronize the start of the arm-swing-forward move with the start of the leg-recovery move to bring the opposite leg forward -- (following the old advice to synchronize the arm moves with the opposite-side leg) -- which is sufficent to gain some work from the arm-swing-forward move. But not the maximum work.

  • 1 for stop of arm-swing-backward could be delayed until after the set-down the leg on the same side.

The easier timing to learn is to synchronize the stopping of the arm-swing-backward move with the stopping of the opposite leg's "follow-through" after its leg-kick-backward move  (following the old advice to synchronize the arm moves with the opposite-side leg). But that easy timing does not generate any propulsive work from the arm-swing-backward move.

It also helps to start and accelerate the arm-swing-backward move before the set-down of the opposite foot -- but my current guess is that that timing is mostly automatic and natural.

calculate entire-body complexity

Results from Leg+Hip complexity:

  • running -- Leg+Hip:  func= 4,  artic= 7.5  (range 7-8)

Upper body moves:

  • add  func= 1-2,  artic= 4  (range 3-5)  for upper body forward-backward (counting the "small contribution" moves as adding 0.5 each to complexity).

Total propulsive moves available from entire body:

  • running:  func= 5-6,  artic= 11.5  (range 10-13),  desync= 2 (or 2.5)

Cycling

seated

Bicycling while remaining (quietly) seated prevents significant contribution of upper body muscles.

standing

Additional upper body muscle moves are available mainly when pedaling standing:

  • pull handlebar upward with the arms (which tends to pull the upper body and hips downward toward the pedal)

  • pull handlebar toward inside with the arm on same side as current leg-push

  • push handlebar toward outside with the arm on opposide side as current leg-push

There's a tricky distinction to be made with the "pull handlebar upward" move: Whether (a) to pull statically ("isometric") to constrain the upper body and hip from moving upward; or (b) to pull with motion in the arm, to push the upper body and hip actually downward some small distance.

(a) increases power to the crank by improving mechanical efficiency: more of the force of the main leg-radial-press down-push goes directly immediately into the pedal, rather than into adding potential energy to the mass of the upper body which will be used to add downward force to the next pedal stroke.

(b) might add power by adding Work to the downstroke. But perhaps there is a range-of-motion conflict between the positive arm-pull and the main leg down-push?

The two "pulling the handlebar toward the side" moves tend to tilt the bike to the side, which tends to move the pedal upward against the pushing leg -- which increases the pushing force between the foot and the pedal.

At low cadences while standing, it might also be possible to add some positive work by using the arms to pull the torso and hips forward through the start of the downstroke. But this does not seem productive for skilled and well-trained riders in typical riding situations, so I'm going to ignore it for now.

At low cadences while standing, it might also be possible to derive some positive work from well-timed vertical "bouncing" of the upper body, which might be enhanced by some Torso up-down moves. But this does not seem productive for skilled and well-trained riders in typical riding situations, so I'm going to ignore it for now.

de-synchronization of timing among moves

I have not surveyed the latest experimental observations analysis of the subtleties of the cycling stroke-cycle, but here's my attempt to provide a numerical estimate of the complexity of its timing coordination, for the sake of comparison.

My analysis of the stroke-cycle shows these points where the amount of propulsive work is impacted by the accuracy of de-synchronization:

  • 1 for transition from pushing down the front to pulling back underneath.

I think there's a temptation to delay the start of lifting the toe up with the ankle-flexion sub-move -- and so miss the opportunity for maximum overlap between the two muscle moves -- instead of starting the upward-lifting immediately as the pedal reaches its lowest point.

which yields a total of 1 timing de-synchronization point.

calculate entire-body complexity

Results from Leg+Hip complexity:

  • cycling seated -- Leg+Hip:  func= 2-3,  artic= 4

  • cycling standing -- Leg+Hip:  func= 4-5,  artic= 7

Upper Body moves -- for cycling standing:

  • add 1 major functional move for pulling upward on handlebars (1-2 articulations)

  • add 2 major functional moves for pulling sideways on handlebars (1-2 articulations each, for a total of 2-4)

Total propulsive moves available from entire body:

  • cycling seated:  func= 3,  artic= 4, desync= 1

  • cycling standing:  func= 7-8,  artic= 9-12, desync= 1

Cycling with "Tacking"