Pole Push Power in Classic Skiing

Ken’s Story

As I was preparing over the summer for my first year of serious racing, I had heard that Classic striding technique was very tricky, and that summer training did not transfer well to on the snow. So I figured the one thing that was sure to transfer well was poling power.  I did lots of double-poling and single "diagonal" polling workouts on rollerskis.  I did weight training for my triceps and abdominal muscles. When I got onto snow in December, I found that my poling was strong on its own and worked great on the groomed snow.  And I found that using my poles helped me get through marginal grip conditions in my classic striding -- indeed some of those days I thought my legs weren't really doing their share. When I got to my big 50-kilometer classic-technique marathon races, I found that most of those had lots of flat and gentle sections where I was not doing Classic striding at all -- because poling was faster and more effective.  And I passed lots of other racers that way.  If I had to point to one "secret" that gave me the most advantage in classic-technique races, it was pole-push power. But apart from racing, I found that double-poling and kick-double-pole are just fun motions to learn and do. 

Tricks often Missed

The first trick is to drop the weight of your upper body onto the poles at the start of the push. Beginners think that poling is all about the arms, but actually there's lots of other muscles and body parts that can help. The simplest is use the weight of the chest and shoulders and head to help push by dropping them down onto poles.

But using body weight is not a "free lunch". You always have to raise the weight of the chest and shoulders and head back up again, and that's take real muscular work, especially by the back muscles.

Some other tricks that lots of athletic skiers miss:

• crunch sharply down in the chest at the start of the push (instead of hinging at the waist) -- to drive the shoulders to help push the poles back. The more forward the shoulders start, the more this helps.

• bend arms strongly with elbows "winged" out to the side, so then they're in position to use the "internal shoulder rotator" muscles to help push the poles directly backward.

• transmit to the skis fully the extra force of chest-crunch and body-weight, by keeping the arms rigid and actively pushing during the first phase of the push. Do not allow the arms to collapse and absorb the force instead of transmitting it.

• double-poling: use forward-foot-thrush to finish the double-pole push with reactive force benefit.

Double Poll

Just do it all with your poles.  

Move both poles together in parallel.  Bring your hands up in front of you to about shoulder height.  Plant the tips in the snow with the shafts of the poles angled back a little -- and then push.  Then bring your arms back up and forward for the next push. 

And there are some tricks for getting more power out of this -- see below. 

What for 

Often used for gentle downhills or flat terrain. 

An excellent motion technique -- but using it long or strong requires special training of triceps, abdominal, and back muscles. 

advantages

Makes an excellent "alternate" to classic stride, because the weaknesses of classic stride are exactly covered by double pole's strengths:  

(a) good for higher speeds than striding: The problem at higher speeds with matching the velocity of the push with the snow surface is easier for the pole tip and arms than it is for the leg and ski with grip wax -- so it's a better "high-gear" motion. The snow-contact distance is longer for the pole-tip then for the leg and ski, because of the geometry of the human body -- so the snow-contact time is longer.  And the shortening of the snow-contact time due to higher speed can be compensated for by applying higher force intensity through the pole and its tip, without it slipping. 

(b) makes excellent use of the abdominal and back muscles.  

(c) less gliding friction than classic stride, because the skier's weight is spread between the two skis. 

Disadvantages  

(a) Not so good for slow speeds. The poling motion delivers less power at lower speeds -- not a good "low-gear" motion.  Each motion has a Speed-Power curve.  In Classic skiing, poling is thought of as a "high-gear" motion, best for higher speeds.   The force must go through the shoulder joint, which is a long way from the surface of the snow -- so its leverage is good for converting shorter muscle movements into much longer snow-surface movements.  But this same leverage ratio makes it difficult to deliver high forces at slow speeds -- so lower power output.

(b) Slow-speed "gearing" problem is worse going up steep hills. Recovering up to the high start position takes significant time -- with nothing else pushing in between -- so when going up a steep hill you lose significant velocity in between pushes.  So the speed at the start of the pole-push is at its lowest -- but the start position of the pole-push is the worst configuration for delivering high forward-push force at low speed.

(c) Inefficiency of using leg muscles to drive poling up hills. In pure double-poling in Classic skiing, using the leg muscles is a major source of the power of poling. This is done by dropping the hips and upper body down and back to drive the poles, then using the big leg muscles to lift the body-mass above the hips up high in recovery to build "potential" energy to be released in the next pole-push. One the flats, using the capacity of these "hip-lifting" muscles like this makes sense -- applying vertical work to drive forward motion. But when climbing up a substantial hill, over 80% of the skier's power is applied to fighting vertically against gravity -- not just moving forward.  The skier lifts the hips and large body mass above them, only to drop it down again to drive the poles, then lift it all that again to really finally move that mass up the hill.  Lifting it once is required, lifting twice it through the same vertical range has the smell of inefficiency and wasted energy.  Moving one part of the body down to move another part forward and up sounds strange and like wasted energy.

Hints

(a) It's OK to plant the pole tips in front of the feet unlike with Classic stride -- because with double-poling there is no grip down-force which this extra pole down-force could disrupt. The faster you're going the further forward you can plant the tips of your poles. But not in front of the hands.

(b) You put less stress on your elbow joints if you "wing" each elbow out to the side a bit, instead of keeping it in a straight vertical plane with your wrist and shoulder joint. It doesn't seem to hurt power any. It's what the pro racers do nowadays. 

Strategy

The racer's strategy is to use clever physics and biomechanics to engage more muscles to push through the poles than just the arms and shoulders:

• "potential energy" lift to engage quadriceps, gluteus, back extensor muscles -- even calf muscles.

• "reactive force" to engage quadriceps and hip flexors. (see below on "thrust lower legs forward")

• forward-shoulder leverage position for maximum engagement of both upper and lower abdominal muscles.

• actively pull legs up off ground during the pole-push, to force full body-weight onto the pole-push.

• winged-elbow leverage position to engage inward-shoulder-rotator muscles.

Therefore the role of arms and shoulders is not just to push the poles back -- but to transmit into the poles all that additional force from all those other muscles.

So the maximum forward-propulsion power is not necessarily achieved thru maximum range-of-motion or forward-extension or backward-extension of the arms. Might be better to compromise the utilization of the arm muscles, to coordinate with the other propulsive muscles.

specific moves for racers

Racers can get more power out of each double-pole push by: 

(a) "crunching" down with the chest and abdominal muscles -- to get the most from this, start it early and strongly. Not just hinge at the waist, but "curl" the whole upper body forward. The upper-abdominal "chest curl" muscles are actually better positioned to push back than the lower-abmominal "waist-bend" muscles. (Note that when poling is done together with skating, the pro racers start the "chest-crunch" of the upper abdominals clearly before the pole tips hit the snow, while in pure classic double-poling the "crunch" is not as early).

(b) Get the shoulders as far forward as possible at the start of the pole-push: so far forward that you're out of balance, and you have to fall forward onto the poles with the weight of your upper body. The further forward the shoulders start, the larger percentage of abdominal muscles can be engaged to push the poles backward, and through a longer range-of-motion. Compare the feeling of the percentage and length of abdominal + chest muscles being used in crunching onto the poles when you stand straight versus when you get your shoulders way forward. In addition to bending shoulders forward relative to the feet and hips, can also do a sort of "forward shrug" and bring them ahead of your lower neck before the pole-push begins. Then during the pole-push, you can pull them back behind your lower neck / upper spine. This forward-to-backward shoulder-relative-to-neck move is already effective early in the push.

(c) pull the legs up off the ground during the pole-push -- to force full body-weight onto the pole-push. If the weight of the legs is resting partly directly on the ground, then the legs are not doing everything they can to use gravity to help drive the poles. This move could be delayed a little later in the push, since the upper body tends to get lifted anyway at the initial contact of the pole tips with the ground, because the poles are closer to vertical.

(d) hands pass by legs low -- at knee level.

(e) get shoulders and hips as high up as possible before starting the pole-push: extend the back, hip, knee joints to straighten both the upper and lower body. These actions build "gravitational potential energy" by lifting the mass of different body parts vertically -- fighting against the force of gravity. Then during the pole-push this stored "potential" energy is released and converted into the "kinetic" energy of motion. Notice that the pro racers also extend their ankle joints -- use their calf muscles to push their toes and raise their ankles -- to build a little more potential energy. Of course getting the extra power from these down-moves does not come for free:  It means that in order to "recover" to get into position to start the next double-pole push, you have to do some work with straightening up your back and pushing up with your legs.  (So if one of the reasons you were double-poling was to give your legs a rest, then you can skip part of that last idea.) Also, sometimes the back does not respond well to large increases in work-load, so start these extra-power things small and gentle, then build up the duration and intensity over several weeks or months. 

(f) when you "wing" your elbow out to the side, try using the "inward shoulder rotator" muscles to help push the pole back -- not just the obvious tricep muscles. Experiment with bending the elbow at a 90-degree "right" angle. Play with finding the strongest combination of elbow bend and elbow wing-out. Your best position might change as your muscles develop in their new roles. But careful not to overdo it at first: start gentle and for a short practice-session duration, then build up the duration and intensity over several weeks or months. Can also play with spreading your hands out wider just before the start of the push. Maybe even try feeling what pushing the poles a little bit inward feels like.

(g) thrust your lower legs forward as the pole-push is ending. This "secret" move works by "reactive force" -- Newton's Third Law, "every action has an equal opposite reaction". Therefore the action of starting the mass of your legs forward makes a reaction of a push backward thru your poles. But have to get the timing just right: the starting of the legs must occur while the pole tips are still pushing against the snow, and the stopping of the legs must occur after the pole tips have come up off the snow. So you have to delay the start, other wise the stopping would come while the pole tips were still in the snow. The sharper and quicker the thrust, the more forward-motion power is added to the overall stroke cycle. If the ankles are back a little just before the start of the thrust, there's more room to accelerate them to a higher maximum velocity during the thrust move.

Usage zone

• When your arms and abdominals and back are getting tired because they're not as well-trained as the legs -- switch to kick double pole or classic stride.
  

• When the hill is too steep and speed gets too slow for poling to be effective, switch to classic stride.