what's here

detail pages

see also


what is this?

This is a description of the sequence of all the leg movements available to effectively help skate forward to go somewhere, along with analysis of the physics of how some of the less-obvious moves are able to contribute to propulsion -- and some hints for how to perform some of the moves more effectively.

  • Some of the moves are surprising, and some of the physics is not intuitive.

  • This description is more detailed and more carefully rooted in physics than anything I've found so far in English. I suspect there are some elite racing coaches who know this stuff (and more accurately), but I haven't yet found where any of them have written it down.

key findings

?? [ this might need to be revised somewhat ]

  • There's a large number of muscle moves available to add to forward-propulsion power (see Muscle Moves page). Some of these muscles are small, but put a bunch of them together and the gain in speed is significant.

  • The sequence of moves available is way more complicated than I ever expected. Skating is at least twice as complicated as running or bicycling.

  • Timing and pre-configuration and sequence are critical for gaining the effectiveness of many of these moves (see Sequence of Phases page).

?? see more specific findings: normal-push moves

implications

?? [ this might need to be revised somewhat ]

  • There's lots of opportunities for improving speed (or taking some load off from the obvious major muscles) thru better techniques.

  • A key puzzle is how to coordinate and manage the complexity: in performance, in learning, in coaching. Few skaters could be expected to understand this complexity. The mission of the gifted coach (or of the "trainer of coaches") is to somehow distill and transform it into helpful and fun.

  • Trying to figure out what works best by rational systematic trial-and-error search is unlikely to succeed -- because lots of different moves work if done in the right context and timing with other moves, but lots of those moves are ineffective or counter-productive if done in a different combination or sequence or timing.

  • If you don't get too worried about arriving at the true "best", there's lots of fun to be had with the learning process -- just trying out different moves and combinations and feeling new rhythms.

story

Several years ago I started trying to figure out how skating worked. I read articles and books. I tried things out in my own skating, how different moves felt to me, sometimes even measured difference in my speed. I took lessons from good coaches. I analyzed videos of elite racers using slow motion and pause and single-frame-advance. I analyzed videos of my own skating. I analyzed the physics and biomechanics, even made some numerical models. It's been fun.

Every six months or a year, I would think I had reached the understanding of how skating worked. But then somebody would point out something new, or I would get bothered by a new question. Then I'd see that I didn't really understand skating and it was actually more complicated than I'd thought. And each new level of understanding led me to experience new magical fun feeling in my own skating.

Now I'm convinced that the motions of skating are very sophisticated and surprising. I'm thinking that skating is the most complicated human-powered propulsive movement on land (or water? perhaps more complicated than freestyle swimming?)

Here I'm writing down what I've learned, to share the sophistication and surprises with other skaters and investigators -- and to get responses that will drive me to a yet deeper level of understanding, and a higher level of fun in my own skating.

What this understanding offers:

  • a framework for trying to make sense of the amazing complexity of skating propulsion.

  • a complete set of options of the muscular moves which are available for the human body to use for skating propulsion.

  • principles that explain why (sometimes surprising) each move is effective. These principles can lead to ideas for how to make it more effective, and a sense of how to feel its effectiveness.

Not -- this is:

  • Not the "right" way to skate.  Rather it shows why there must be several "right" ways, for different skaters with different goals in different situations.
  • Not something which most skaters need to understand -- or even read.  Skaters will get much more help from taking a lesson (and some help from reading the Secrets).
     
  • Not something every good instructor and coach needs to understand. (though I think it's good for any instructor to try to at least read, to get a sense of big the magic can get, and a sense of how things can get confusing for their students).
  • Not the right set of moves.  Rather it's a set of options for moves -- from which each skater can select to form their individual style (likely with a different selection for different situations).
  • Not a manual for learning.  This understanding is missing two pieces critical for learning by a skating human: (a) the subjective non-rational images which the conscious human mind needs to handle the complexity of the physics; (b) the experience by our unconscious untra-sophisticated neuro-muscular control centers of new possibilities of propulsion, through being exposed to new moves in cleverly-designed bodily exercises. For some attempts on filling in those pieces, see some of the notes in the Secrets.
     
  • Not about tricks, or dance, or jumps, or slalom.  The focus is on propulsion: getting from one place to another by skating.
  • Not about slowing or stopping.  The understanding of those is very important, but the focus here is on accelerating and maintaining speed while skating.
  • Not my final correct analysis.  For a human activity this rich, there's plenty of room for building more -- and surely corrections to be made to what's here.

why it's tricky

The most effective moves for skating are both tricky to figure out and tricky to learn to perform. And perhaps even tricky to keep on performing all of them consistently after learning them.

The number of moves that can be used for propulsion in skating is way more than in walking, running, or bicycling -- like twice as many. Some of these moves for skating feel natural and obvious because they're like running and walking, but many are unexpected because they push more sideways than forward.

Timing is important for many of the moves of skating. A move which is helpful in one phase of the leg-push sequence might be counter-productive in another phase. One move is helpful in the early phase, and then the opposite move is helpful in a later phase of the leg-push sequence. Almost any interesting tip or idea about what works for skating is true and helpful for some phase -- and false or at least misleading for some other phase.

What this website offers is a "framework" for navigating the overall complexity (see  sequence of phases), and some principles for grasping the different kinds of strangeness of some the individual moves (see underyling principles).

sequence of moves

?? [ this might need to be revised somewhat ]

The phases available in the leg-move sequence are:

  • R - Recovery phase

  • 0 - Set-down phase

  • 1 - Underneath push phase

  • 2 - Central push phase

  • 3 - Extension phase

For lots more detail on the sequence of phases and moves, see sequence of Phases.

There's also a sequence for Double-push technique.

variations and overlaps

In some person's actual skating, some of these phases might be omitted. Many people skip parts of phases 1 and 3. Some phases often overlap with others: especially phase 2 gets blended or submerged into phase 1 and/or phase 3.

Two legs: Of course there is overlap between the phases of one leg with those of the other. Obviously phase R of one leg overlaps with at least phase 2 of the other leg, and it's not surprising that phase 0 could overlap with some pushing phase 3 (or perhaps 2) of the other leg. What really surprised me is that in videos of elite racers there can be some overlap of Phase 1 with Phase 3 -- both legs are delivering forward-propulsion power at the same time.

findings

?? [ this might need to be revised somewhat ]

  • Phase 1 just after set-down is already directly propulsive, not just passive preparation.

  • Set-down phase 0 can already be propulsive. Even the Recovery phase R can add propulsive work.

  • Having it both ways:  When skating, some joints can deliver net power in both directions: e.g. flexion and extension are both effective for forward propulsion -- but only if done in the right timing and configuration.

  • Skating is half natural and instinctive, and half magical and counter-intuitive. Some of the effective moves in skating are similar to what we do instinctively from walking and running -- but lots of the other effective moves are completely different from walking or running, and require a whole different unexpected set of feelings and concepts.

For lots more detail on the sequence of phases and moves, see sequence of Phases.

more . . .

implications for learning

knowing

  • Understanding rationally all these moves and phases and principles is not important (or likely) for most skaters. The details are intended mainly for scientists and a few advanced coaches -- and for a few skaters who just love playing with the feelings and ideas of different moves.

  • Most skaters will learn these moves by various non-rational feelings and images -- because our rational conscious mind is simply not designed to grasp and handle this degree of physics/biomechanics complexity.

  • It's not surprising that a skater will hear different and apparently contradictory concepts from different coaches, or contradictory reports from their skating friends about "what worked".

performing

  • Few skaters are going to learn to perform all these moves. Fewer are going to be able to effectively coordinate them together.

  • Selecting a subset is a key step in the learning process. What is a good subset will be different for each skater -- depending on goals, athletic abilities, history, current stage in development. There are many "right" ways to skate.

  • A gifted and experienced instructor/coach is very valuable for helping each skater find a good subset of moves to focus on, and to experience the feelings and images that will enable learning them and coordinating them.

  • Only a few instructor/coaches will both understand the full complexity of the moves and be good at helping each human skater to find their individual feeling and performance of their individual subset.

  • Lots of other instructors will provide helpful learning situations and fun experiences even without understanding most of this.

racing at the elite level requires

  • learning most of these individual moves, and the basic timing of each move in the sequence of phases.

  • coordinating fluidly combinations of the moves (while the required complexity of this coordination might exceed what the capacity of the neuromuscular control centers of the normal human brain).

  • muscular development: developing the appropriate profile of speed, endurance, and strength of each muscle used in these moves. (not that each muscle gets its own exercise).

  • optimizing the selected subset and proportional emphasis on different moves for specific terrain and race-strategy situations.

  • But isn't V02max capacity the critical limitation on athletic power, so how can adding more muscles really help? -- see Questions.

see also

[go/motion/z_text_line.htm]

concept words: skating skate skates skater skaters push glide inline inlines ski skiing snow roberts

skating: skate skates skater skaters push glide

inline inlines ice speed speedskate speedskating speedskater speedskaters roller

technique: techniques technical theory theories theoretical physics physical biomechanics biomechanical mechanics mechanical model models concept concepts idea ideas