Cross-country skiing is a primarily aerobic sport. The best way to develop your aerobic system, and even your higher end fitness (V02 max and lactate threshold) is with easy to moderate (60 to 80% of max heart-rate) intensity distance (45min to 2hr) sessions. This type of training comprise about 80% of the training load, even for elite ski racers.
This being true, it is also the case that the training week should be built around one to three harder training sessions.
A harder training session is either a short hard session or a long easy session. For instance many programs are built around two interval sessions and one long (3hr) easy (heart rate around 70% of max) session.
Your body adapts to a certain stress after 4 to 6 weeks and so if you don’t change that stress, doing what you have already been doing will only serve to maintain what you have built.
It can be helpful to look toward your racing season and plan backward. You should end up with a plan that builds toward the racing season. The basic idea is to build your aerobic base over the summer, work on more race like aerobic and anaerobic fitness in the fall and early winter, and race fast in the winter.
In the summer then you would consider doing mostly easy to moderate intensity workouts with one session a week of harder training, and some strength training.
Monday: speed and spenst. Spenst = as per the spenst email. Start the workout with a warm up, spenst and then do speed. Speed = controlled efforts at higher than race pace of 15 to 30 seconds in ski terrain. Start with 5 to 10 sprints and build to around 20 taking 2 to 5 minutes rest between. Or you can simply build sprints and spenst into a distance session so that as you run or rollerski along you sprint or jump up hills as you come to them.
Tuesday: Easy distance session (1 to 2hrs at around 70% of max hr). Strength training = high repetitions (20 to 30) with lower weight. Weight should be such that you cannot do more than 3 sets of 20 to 30 (you finish the first set no problem, struggle at the end of the second set, and have a tough time getting 20 to 30 on the last set.) Focus on ski specific strength including a lot of stomach and back work.
Wednesday: Easy distance or off.
Thursday: Easy distance and strength (specific strength on rollerskis is great).
Friday: Easy distance or off
Saturday: Intervals. Build up to higher intensity as the fall goes on. Start with intervals of 5 to 10 minutes with 3 to 5 minute rest between at 80 to 90% of max hr. Build up to intervals of 3 to 5 minutes at 90 to 95% of max hr. Total “on” time should also increase as the fall goes on. Start with 10 to 15 minutes of “on” time and build to 30 or 45 minutes of interval time.
In all cases intervals should NOT leave you totally wasted. At the end of your interval session you should always feel like you could do one more, and with pacing you should make the same distance with each interval (every 5 minutes should take you the same distance). If you go shorter each time than you are going too fast.
Sunday: long easy distance. Hr 60 to 70% of max – 3hours.
This is only an example. As the summer/fall/early winter goes on you extend the duration of the workouts gradually, making sure you get lots of rest so that you are getting stronger and feeling better rather then getting more and more tired as the summer goes on. For instance, you could do the above week for two weeks then take one week easier before returning to the above week schedule. For example: Week one = 6 hours, wk 2 = 6hrs, wk 3 = 4hrs, wk 5 = 7hrs, wk 6 = 8hrs, wk 7 = 5hrs, wk 8 = 7hrs, wk 9 = 10hrs, wk 10 = 6hrs… build up so that your biggest weeks are late in the fall or early in the winter.
Easy Aerobic work = 60-70% of max heart rate (work off of 190). I think you will do most of your easy work around 120 to 140 beats per minute. Working at 1 to 3 hours at this intensity is the primary means to build endurance.
Moderate Aerobic work = 70-80% of max, for you 135 to 155. If working for 1 to 3 hours is not possible, because of time constraints you will do work at this intensity for less than one hour.
Hard work = 80% +, most of your work here should be comfortably hard, at a speed that is challenging, but doesn’t send you to bed for a week. You build up to harder and harder work as you get used to it. That is important.
Speed = not done by heart rate. Simply go as fast as you can staying in control and using good technique.
Plan one day a week of intervals: 2 min, 3 min, 4 min, 5 min, 4 min, 3 min, 2 min, (take equal recovery between intervals) at a pace that is challenging, but that you can do each interval and the whole workout and feel like you could still do more — take note of what your heart rate is, but don’t base the workout on heart rate — do it on feel until you get a notion of where you really are fitness wise.
Plan one day a week of speed: do 15 second efforts with 2 minutes of active rest between each)
Plan one day that is at least 2 hours and at most 3 hours where you keep your heart rate above 115 and BELOW 140 bpm.
Do some strength stuff 2 to 4 days a week — can be a 10 to 30 minute routine.
The rest is easy to moderate aerobic work.
An example of a summer week for an intermediate competitive skier…
Tuesday: easy run or rollerski or bike with 5 to 10 20second sprints with much time in between each sprint. Strength training.
Wednesday: easy run or rollerski or hike
Thursday: off or easy
Friday: easy/medium run or rollerski or bike. Strength training
Saturday: medium/hard run or rollerski. Aerobic (comfortably hard, not so you are dead after each interval, but so you are tired after the session.
Sunday: long easy run or rollerski or bike.
As the summer goes on you extend the duration of the workouts gradually, making sure you get lots of rest so that you are getting stronger and feeling better rather then getting more and more tired as the summer goes on. For instance, you could do the above week for two weeks then take one week easier before returning to the above week schedule. For example: Week one = 6 hours, wk 2 = 6hrs, wk 3 = 4hrs, wk 5 = 7hrs, wk 6 = 8hrs, wk 7 = 5hrs, wk 8 = 7hrs, wk 9 = 10hrs, wk 10 = 6hrs… build up so that your biggest weeks are late in the fall or early in the winter.
There is a lot of training material out there, but this is the basic idea: training breaks the body down, rest builds it back to a level higher than before training. Remember REST builds the body up.