|
Can I ski like Petter?
Petter Northug Jr. gets lots of attention for his amazing acceleration speed.I would like to know what specific technique skills enable him to be so much better than all other top racers. Many of us would love to practice the ski movements that make him go fast. Thanks
RE
Dear RE,
When I assess Northugs' skiing technique, I see several key elements that distinguish him from other skiers;
1. He maintains a very stable body position with little change in body position and range of movements between race pace and sprinting.
2. When he shifts gears he maintains full range of movements while increasing the quickness of the poling and kicking movements. It appears that there is a dramatic increase in frequency or tempo but I believe it to be more related to the incredible speed of his movements. (Remember range of movement or stride length, increases with speed. So increase stride length or range of movement is an effect of increased power output)
3. Even at maximal speed you can see relaxed movements patterns and a relaxation phase at the finish of each movement. For the movements to be quick they have to be relaxed.
4. Most important is the timing and the quickness of the weight shift. Petter's weight shift, center of mass, movement is early, quick, and complete. The early initiation adds impulse to the kick and helps to keep the hips/center of mass up and forward.
5. While I have no information to support this, I believe Northug must practice his accelerations very often in training to maintain good technique at very high speeds and to develop the physiological capacity.
For those readers who are cyclists the concept we are discussing is comparable to two riders pedaling up the Alp di Huez. Both are riding at the same speed or power output however; one is pedaling a low gear at 90-95 rpms, the other grinding a big gear at 55-65 rpm. The rider pedaling at a fast cadence has more relaxed movements, is using less muscular force, and is producing power more efficiently. The rider pushing the big gear will likely fatigue earlier because of the high force output required, and the big gear pusher will be unable to quickly respond to any sudden changes in pace. This is the fundamental technical difference between Northug and the rest!
Following I will provide several descriptions and cues that will help you practice and feel these concepts. Also, you can see a complete presentation of skating technique that will provide visual of these points on my web site.
http://jimgalanes.com/uploads/Skate_Technique_Progression.pdf
- On roller skis or skis, double pole for some distance, experiment with a heavy increase in force, then reduce the force and strive to feel light and quick in the poling motions. The objective is to increase power by being relaxed and increasing the speed through the poling movements. This can also be done on a Concept 2 double pole machine where you can see how the wattages change.
- The timing of the weight shift from ski-to-ski varies with the speed. In essence we are moving the body weight off each ski when it is at or near peak velocity. For the purposes of developing the correct timing and feeling, the timing of the weight shift can be linked to the poling movements. In the V1 and V2 try to initiate the weight shift right after you have compressed onto the poles. Imagine the hips, center of mass floating forward and over the new gliding ski. In any case the weight shift has to be initiated well before the poling hands pass the hips. Otherwise the kick will be late, the hips will sink down and back, and the potential power production reduced. This weight shift occurs prior to the peak kicking force and adds impulse and quickness to the kick. Similar feelings should be developed in the kick. The kick should create a feeling of quickness not force. If a kick feels strong, chances are that it is slow. In short, the faster you want to go the faster the weight shift and kick must be. We are not trying to kick the body from ski to ski. , that would indicate that the majority of the kick power is being used to facility the weight shift, rather than to create speed.
Now the rest of the story...
What makes Petter Northug so fast is not only his technique but multiple factors including; muscular and neuromuscular factors, physiological factors and of course technique. In an article to be published in the European Journal of Applied Physiology, Øyvind Sandbakk, a PhD candidate in the Norwegian University of Science and Technology's Human Movement Science Program, reports, "Skiers need high aerobic and anaerobic energy delivery, muscular strength, efficient techniques and the ability to resist fatigue to reach and maintain top speeds races".
Oxygen uptake is arguably the most important factor for good performance in cross country. But athletes also face a limitation when oxygen uptake cannot cover the required energy cost. The athletes with the ability to work over their maximum oxygen uptake and those with greater anaerobic capacity, stand out in sprint cross-country skiing and in mass-start races where intensive bursts of speed are required. Dr. Norman, a Canadian biochemist has estimated that in elite races, a skier needs to be able to work 120-150% of maximal oxygen uptake on the uphill parts of the course. These estimates imply that energy must come from sources other than aerobic metabolism, and that recovery must take place during high levels of work. This requires the highest values for maximal oxygen uptake, a tremendous ability to buffer the byproducts of the anaerobic metabolism quickly, and large glycogen stores.
A crucial aspect of technique is the ability and the understanding of how to increase power production in an efficient manner. When producing power with the upper body and legs the skier must be able to recover quickly from the tremendous physical demand. The ability to resist fatigue is tightly coupled to the ability to maintain technique and keep up the cycle lengths and frequencies during a race.
Now that we have established the foundation of what makes top skiers like Northug fast, we can evaluate what skills and capacities we can work on develop to improve of skiing speed and our ability to accelerate in races. While most of us do not have the physiological capacity or an elite skier there are several things we can do to greatly improve.
- Develop a solid aerobic base consisting of endurance training at the proper intensity and do an appropriate mix of intervals, 3-8 minutes in duration at 90-100% of VO2max, or 90-95% of maximal heart rate.
- Improve anaerobic capacity, close to race season, through maximal intervals of 60-90 seconds with recovery time of 3-5 minutes.
- Improve maximal strength and power through a periodized strength program. See previous article I have written on maximal strength training.
- Last but not least, improve technique in every training session with a focus on how to efficiently produce power. The equation for power is . There are two ways to increase power and subsequently, speed. 1.) Apply more force or 2.)Reduce force and decrease the time through the full range of movements. I see most skiers too far at the force end of this spectrum which results in an inefficient and unsustainable production of power. The focus for most skiers should be to focus on the quickness of movements while maintaining a range of movements that is appropriate for the speed. This focus will develop efficient endurance at low intensity levels, and high power outputs in the more intensive workouts. I believe this technical focus combined with increased aerobic and anaerobic capacity, improved muscular strength and good technique are the keys to fast skiing.
|
