The exact difference between trail and sky race is difficult to tie down however it is generally accepted that sky races are characterised by routes which reach above 3000m of altitude in mountainous environments. However, since many races, which are defined as trail, reach these same heights, while some sky races may fall short of this parameter, the boundary between the two becomes rather vague. Within the context of short races the main difference can perhaps be identified in the steeper and more “violent” nature of the climbs and descents of the Sky races. This difference will dictate the slightly different approach to training for Sky Races, rather more similar to that utilised for VK.
Short Trail
Within the context of short trail races it is very rare that an athlete can experience problems with nutrition or hydration, therefore, while it is certainly advisable to experiment with race day nutrition and hydration (particularly pre-race nutrition) this may be considered a minor factor. On the other hand strong motor patterns and skills will be essential in ensuring the best possible race performance and these should be supported by a strong mental approach.
The majority of short courses will entail at least one, but maybe more, medium long up-hills linked by consequent descents and most probably flatter areas on uneven and winding paths. The scope of race specificity training in this case will concentrate on the motor patterns needed to take on this terrain and the skills required to maintain speed and leg turnover on difficult terrain.
During the speed and strength phase we have seen how short uphill intervals can be utilised to boost anaerobic performance. In this phase the length of these intervals will be increased to distances of between 400 and 800m (3-8’). The number of intervals to be performed will vary from 6 to 10 depending on the length of the intervals and the present state of form. In any case the exertion should remain comfortably below the anaerobic threshold (75-85% of HR Max) and at a level, which will allow all of the intervals to be performed at the same or similar pace.
Between each repetition the rest interval should be equivalent to between 50-80% of the time required for the uphill phase. Generally the rest interval should be performed as active recovery in order to mimic race continuation and therefore a slow run back to the starting point. However for those having the good fortune of a longer hill (for example 2 – 3 kilometres), a continuous upward direction could be maintained in which faster periods are followed by slower recovery running. The steepness of the hill should be sufficient to elicit an effective involvement of the muscular and neurological adaptations but not too steep as to prevent an effective running action. In general this can be achieved on a medium slope (approximately 10% - 100 metres of height gain for 1000m of distance. A slope on natural terrain should be preferred to asphalt due to the added training effect of an uneven surface.
A similar protocol should be undertaken for descent intervals, however in this case the chosen terrain should be steeper and more intricate in order to stimulate the muscular, neurological and coordinative adaptations necessary for rapid down hill running. As with the shorter hill interval protocol, a third option is that of creating a quadrilateral circuit in which there is a hill ascent and a hill descent connected by two reasonably flat zones for active recovery.
Maintaining a fast pace over uneven, winding and constantly changing terrain is complicated. The number of muscular and neurological reactions, which the feet, ankles, legs, hips and upper body must take in and adapt to, while running fast over such terrain, during a race are enormous. The only way to train these reactions is to practice running under similar conditions and on similar terrain. Such runs may be performed in various ways. Fast tempo runs of between 40 – 60’ at approximately target race pace or progressive runs starting at below race pace and working up to a fast finish, alternatively cruise intervals of 5-10’ at above race pace with short 2 -3’ intervals of active recovery, and of course the classic fartlek.
Even the shortest trail race (15 – 20km) lasts between 90 to 120’ and therefore the aerobic, fat burning zone will remain the principle area for the supply of race energy. Therefore it will be important even during the race specific phase to continue a regular weekly session of aerobic or MAF running in which fat adaptation can be maintained and this will also serve as an active recovery between other more stressful sessions. Every two weeks this slow run should be extended to be approximately as long as the chosen race distance and if possible on similar terrain in order to elicit specificity.
Sky Race
As mentioned in the introduction sky races are usually characterised by steeper climbs and descents than trail races and in almost all cases reach heights of, or above, 2000m of altitude.
The rather more “violent” nature of the terrain to be covered signifies that the muscular and neurological adaptations to be trained are more important and necessitate a more focused approach.
Therefore while the training sessions as described above for short trail races can be useful for sky racing, it will also be important to add a number of sessions in which both uphill and downhill running are conducted in the zone of the anaerobic threshold (85-90% HR Max) and on terrain which is more similar to that of the actual races. Therefore the chosen terrain will be between 15 – 20%, preferably single track or similar. The repetitions can be from 200m up to 800/1000m. Due to the stressful nature of these sessions it is advisable to utilise either passive recovery or extremely light active recovery between the repetitions for 60% up to 100% of the time required to complete each section. On a longer climb or descent the total distance can be broken up into various sessions, and even of varying distances, in order to elicit different paces and different percentages within the cardiac range (but in any case remaining within or close to the zone of 85% - 90%+ of HR Max).
Similar tempo runs to those described above for short trail training should also be used in order to stimulate the same muscular and neurological adaptations, while easy aerobic runs should be used as a form of active recovery.
One of the main differences between trail races and Skyrunning races is that of altitude. While the required 2000m limit is not always respected it is true to say that the majority of Skyrunning events do reach this height and a number of them reach as high as, or exceed, 3000m. Any form of anaerobic exercise, including running, at this height where air density, and therefore also oxygen availability, is lower can rapidly become unsustainable if correct acclimation has not been conducted. Research has shown that the average reduction in Vo2 Max at 2000m is in the range of -5 to -10%, while at 3000m the reduction can be -15% or more. There is no easy solution to this problem. Either you have the opportunity of training frequently in similar high conditions, or you can afford the luxury of an Altitude Tent (tent like structure in which the lower air pressure of high altitudes can be simulated, usually utilised for sleeping).
Some acclimation advantage can be gained by arriving at the race venue at least one week before (but 10 days may be more appropriate) and being able to train and sleep at higher altitudes than usual. Periods of less than a week have been shown to be ineffective or even counter productive in that the process of acclimation lowers performance before improving it. This is due to a drop in plasma volume during the maturation period of new blood cells. In this case the advice is to arrive at the race venue the same day or a day before.
Vertical Kilometre
Participation in VK races, but also 2 or even 3VK, is rapidly gaining in popularity. It is fairly easy to take part in such a race, but not necessarily to finish it. The total distance to be covered for a single VK is small (from the 1.92 kilometres of Fully to the nearly 5 kilometres of the Limone Extreme) though the 1000m of climbing will remain the same. Clearly the average gradient to be faced will vary greatly from the nearly 50% grade of Fully to the 20% grade of Limone.
Anyone who has a minimum of mountain running experience can get to the top but competing successfully is a totally different story. Not only considerations of VO2 Max and overall muscular strength will play a major part in deciding the outcome but also such factors as technique and mental strength.
On top of a highly developed and efficient aerobic system, in which MAF can play a key role (it is interesting to note that many of the top VK athletes utilise cross country or back country skiing as winter cross training, sports which entail a high degree of aerobic fitness), it will be important to raise the anaerobic threshold as high as possible and in any case above 90% of Max HR.
The optimum method for training the anaerobic threshold will of course be steep uphill intervals between 15-25% grade. There are two types of intervals, which can be utilised with slightly different emphasis and result.
Short
In this case the distance to be utilised will be from 50 up to 100m. Speed should be almost maximal and a sufficient recovery period should be allowed between each repeat so that speed is not affected. Sets of 10 intervals should be utilised with a total recovery period between each set. Start with one set and build up to 3 or 4. This type of training stimulates both the cardio vascular system and the neurological system to produce stronger leg muscles.
Medium
These intervals should be performed on longer slopes between 200 up to 300m. In this case speed should be more controlled so that HR reaches approximately 90 - 95% of HR Max by the end of each interval. Recovery can be conducted as a slow jog down to the start. Sets can be between 6 up to 10 intervals with a five-minute recovery period between each set. From one to 3 sets can be conducted.
More specific race training will be conducted on similarly steep but longer slopes. In this case the intervals will be between 500m up to 1000m. Speed should be monitored so that heart rate arrives and is maintained at around 90% of HR Max. Recovery can be conducted as a slow jog back to the start. Sets of 4 up to 6 intervals are ideal. If a second set is to be conducted a suitable recovery period of at least five minutes should be allowed between the sets.
In the period leading up to race season longer intervals of 1000m up to 2000m can be utilised in order to mimic race conditions. In this case the height to be climbed (providing the chosen gradient is at least 20 – 25%) will become closer to that of the actual race, therefore particularly specific. The heart rate should be kept between 85% to 90% of HR Max though may exceed this during steeper gradients or more technical parts of the climb. Up to 4 intervals can be performed, so as to accumulate a total distance and climb equivalent to, or more than, the actual race. Recovery should be conducted as a slow jog back to the start. During these training sessions it will be important to make personal experiment with technique. When is walking quicker or more efficient than running, should hands be used to push down on knees or are sticks better? Pace and effort can also be experimented with. What happens if speed is slightly increased, if HR exceeds 95% how long does it take to bring it under control and will that compromise further progression and speed? Are shorter steps with a higher cadence better than longer steps at a slower cadence?
Occasionally it may be interesting and useful to run an entire VK during a training session. This can be utilised as anaerobic training, experimentation with technique and, if pushed as hard as possible, as training in mental strength. Naturally such sessions should be used sparingly and should always be followed by appropriate recovery days.