Offset Timing of pole push

Who is it for?

For competent skiers

Offset pole timing provides a natural time in the stroke cycle to lean on your pole for balance-recovery -- without hindering your grip with your ski for leg-push.
If gliding long on each stroke is your idea of fun, this is the way to get it. Indeed you can exaggerate the pole timing (see the "linked kick-single-pole" variation under Learning) and glide even longer.
If you like learning new things, pole timing is a fun thing to play with.
But you must already have solid balance and weight commitment on a single ski as a prerequisite.

For racers

Offset pole timing is what all the World Cup racers do in their classic "diagonal" stride. Check it out: Compare the discussion below under Details of the offset motion with your favorite Classic race video in slow-motion and pause.
It's the only way to get the full power out of your pole push.
It reduces gliding friction.

Options for Pole Timing

There are three basic options for pole versus leg timing:

(a) synchronized start and finish;

(b) sequential non-overlapping;

The most efficient timing for normal classic stride is (c): The new pole-push starts while the leg is still gliding. The next leg-push starts only after the pole-push is at least half finished, and the two pushes overlap briefly. Then the pole-push finishes, and then the leg-push finishes.

Beginner's classic stride uses (a), but also so does expert hill bound technique.

Kick double pole uses roughly (b) -- so advanced classic stride is not the only example of pole timing not synchronized with leg-push.

My story

I had always thought that the pole synchronization for classic striding was like walking: I bring each arm forward with the opposite leg, and I push the pole back together with pushing on the opposite leg. Feels very natural: the pole-push "helps" the leg-push. And that's what books say to do. That's what I did in my first big race. Then I got serious about working on my striding technique, so I bought my first video, called something like "Dryland Training", by Team Birke. They put a lot of emphasis on what they called "syncopated" poling. So I worked on that timing during the summer on rollerskis. It was a challenge at first, and fun to work through the learning of it. Once I got it down it felt rather cool to be able to do it. Then I got my first brief chance for some live coaching, so I made sure to show off my new pole timing. But there was some misunderstanding with that rather busy first coach, and I thought he was saying it was a mistake, and that I should go back to the natural synchronization like walking. Looking back on it now, I think the confusion was because what I was demonstrating then was actually "sequential non-overlapping" pole versus leg timing, not true "offset and overlapping" timing. This forced me to really think about which timing was better, so I looked very carefully at slow-motion vides of elite racers on snow to see their timing. And I wrote a note about the pros and cons and the issues and questions and posted it to the rec.skiing.nordic discussion group. From some of the folks there I got some helpful stimulating ideas that developed my thinking further -- and that's what I've tried to lay out here.

Advantages of offset timing

allows a fuller range of pole motion. The distance of static snow contact of the pole tip is longer than the distance of static snow contact grip of the leg-push ski, because of the geometry of the skier's bones and joints. You can verify this on dry land. So if the pole-push is initiated simultaneous with the leg-push, and then terminated with the end of the leg-push, then its time and distance were shorter than what they could have been. A simple way to give the pole-push more time and distance -- to gain its full effectiveness -- is to start it before the leg-push. (said Scott Elliott, on rec.skiing.nordic)

delivers more forward push -- without hindering grip friction. Increasing the range of pole motion at its initiation -- start it higher and more forward -- is excellent for delivering more forward push, because (a) it enables the abdominal muscles to be used more effectively; (b) the upper body can "fall" onto the pole, which can convert most of its down-force into forward-motion power. But there is a big problem with starting higher and more forward: The pole is near to vertical, so at first much of its force is directed downward. Now basic physics says that "every action force has an equal and opposite reaction force" -- and that means that this pole-push initiation results in a substantial upward force component. See the Pole-Push Angle Diagrams page, especially the second diagram. So if I make this pole-push initiation during my leg-push, that upward component counteracts my committed body-weight bearing down on my ski's grip zone. So it ends up hindering my grip friction -- not good. The solution is to make this strong pole-push initiation before I start my leg-push. This point is a bit tricky, since even with offset timing the pole-push continues during the leg-push, so there is still overlap -- and therefore still some hindering of grip friction. But the down-force of the pole-push is larger at its initiation, when the pole is closer to vertical. So that's the sub-phase that is most important not to overlap with the leg-push. In the later part of the pole-push, the pole much less vertical, more pointing out behind (see the fourth pole angle diagram and fifth pole angle diagram), so the proportion of down-force is much less -- even though there is still some hindrance of grip, it's worth it for the forward-motion help of the pole-push.

enables the "back lift" move for better grip
better for grip (even without the "back lift" move) because it provides a natural time for me to get in the habit of making those "lean on a near-vertical pole for balance-recovery" moves -- without hindering my grip friction. I get out of balance lots of times in my ski striding (doesn't everybody?). Leaning down on a near-vertical pole is often a helpful move to recover from that. But if I put that "lean" move during my leg-push, it reduces my grip friction (see Pole-Push Angle Diagrams page, especially the offset pole-push initiation diagram). Offset pole timing gives me a good time in the stroke cycle to put that "lean" move -- before the next leg-push begins -- during the glide phase from the previous leg-push. That way it doesn't hinder my grip.
better for glide because pushing down on the pole while still gliding (before starting the leg-push) takes some of my body weight off the ski. With less weight pressing it into the snow, the ski glides better.

fun to learn -- fun to do.
looks mysteriously sophisticated. People sense that there's something "syncopated" about your stroke rhythm -- but it's hard to figure out exactly what it is.

uses the pole-push force to "fill in" the time gap or "dead spot" between leg-pushes. This keeps my forward motion smoother.
handles "extra" down-force more efficiently. If I use extra down-force (beyond committed body-weight) to get more grip friction, that has a side effect of a second delayed "landing" down-force -- which could slow my glide ski and put temporary extra work on my leg muscles to absorb it. With offset pole timing, I can transmit some of that "landing" down-force into my pole-push -- so it doesn't slow my glide, and it can help push me forward.

Disadvantages of offset pole timing: The only one I know is that it takes time to learn it.

Details of the offset motion

A key checkpoint of Classic technique is not to start the leg-push until the pole-push hand reaches the legs (I first saw that idea in an article by Lee Borowski in The Master Skier). Scott Elliott wrote (on rec.skiing.nordic group): "the pole push has to start before the leg push, which generally starts about the same time as the poling hand reaches the body. This is called the pole assisted glide phase." Then the pole-push continues, overlapping together with the leg-push phase, "until the hand is extended behind the body."

Actually when I analyze slow motion videos, it looks to me like the elite racers start their kick just before the pole-push hands reaches the leg. Jim Farrell wrote (on rec.skiing.nordic group): "The synchronization question is something we worked on in our FinnSisu group last winter. Aided by video tape analysis, we were able to break down the timing frame by frame. If both your hands are passing by each other just as your legs are coming together, then your kick occurs when you are finishing the last half of the poling stroke with one arm while the other arm is recovering forward well before its pole plant. The kick drives your opposite knee forward, the torso down the trail and the same side arm up to the pole plant position. This timing sets you up for the natural diagonal stride, right arm forward and right leg back simultaneously. (If you planted the pole when you initiated the kick, your arms would be 'diagonally' opposed when the legs are roughly parallel.)" But even so, I still think that delaying the kick until the hand brushes the leg is excellent as a mental image -- and I find it worthwhile sometimes to check that I am literally doing it in practice.

Clarification: The motion sequence is not: start pole-push, then finish pole-push, then start leg-push. That would be "(b) sequential non-overlapping" under the "timing options".

How to Learn it

I found learning offset pole timing lots of fun. It opens up a whole new area for "playing" with balance and rhythm, inventing new moves and variations.

Do you need an instructor or coach for this?

While having a good instructor is very important for making the key breakthrough into solid balance on one ski, I think it's possible to learn pole timing with a video camera and a partner to hold it, and a video player with slow-motion and pause controls -- provided you really have the solid balance on one ski already. The difference is that learning solid balance and weight commitment depends on a complicated interaction among ski flex, grip wax (or waxless pattern), body position, pressure distribution, etc. -- so it's tricky to sort out what's going right and what's going wrong -- and some of those key factors are invisible. With offset pole timing, the key checkpoints are fairly straightforward -- and visible, once you get accustomed to looking at slow-motion video. I learned it without a coach. If you're not using slow-motion video, I suspect you'll need a coach or instructor who's pretty serious about technique details and with lots of practice identifying subtle timing differences -- likely someone who has coached serious racers. One complication here is that some American instructors and coaches are fuzzy about pole timing, so you might have to first educate them -- perhaps by somehow forcing them to analyze slow-motion videos of World Cup racers, until they can see that it's real.

Here's the learning sequence I used to get my offset pole timing:

(0) Fundamental pre-requisite is solid balance on a single ski -- with lots of practice skiing without using poles.

(1) Start by learning kick-double-pole. This is the "(b) sequential non-overlapping" timing.

(2) Next learn "kick-single-pole": same timing as kick-double-pole, but push with only one of your poles.

(3) Link together a sequence kick-single-pole strokes on alternate sides. This results in new variation -- call it "linked kick-single-pole". It's like classic diagonal stride -- but with "(b) sequential non-overlapping" pole timing. This variation is great if you enjoy long gliding. Anyway, it forces you to get away from the usual beginner's synchronization. But is still not the most efficient pole timing, so . . .

(4) Learn to not delay the leg-push so much: Start the leg-push as the pole-push hand reaches the legs, then finish the leg-push and pole-push together. (Find the middle ground between the "linked kick-single-pole" variation and beginner synchronization).

(5) Refine the timing -- have fun playing with it. After a while you're doing it without thinking. It gets easy for your body's muscle control processors to find the offset rhythm, because they can sense the difference in the biomechanical length of ground contact of pole-push versus leg-push motion.

Another approach might be try to jump directly to offset pole timing, and skip over steps 1, 2, and 3 (there is no way to bypass step 0). I assume some key exercises for this approach might be:

Start the pole-push "early", and soon as you get your arm forward. delay the start the leg-push, until pole-push hand brushes the leg.

But let me say in favor of my longer learning sequence:

kick double pole is just a useful technique in itself to know (and it's fun).

the "linked kick-single-pole variation" is a great way to practice improving balance even further. And for learning a new motion, some folks find it helpful to exaggerate it at first.

"linked kick-single-pole" is the way to extend the fun of long glide even longer. And it's another variation to fight the boredom of some advanced skiers.

what's the big rush about learning this anyway?