Q: Would it be safe to assume that a skier that has a few years of training can maintain a Level 4 (near the bottom of that level) for approximately an hour? How about for a full 50km?
A: Typically for a 20 km race a skier will start in Level 3, then drift between Level 3 and Level 4 for the middle of the race (harder on uphills, recover on downhills), and then finish in Level 4 for last couple km. Individual athletes will have differing lactate thresholds (% of hr at which they begin to accumulate lactate) but it is safe to assume that a skier’s zone will be between 80 – 90% of his/her HR max.
A good method of figuring out your target HR zone for the race would be as follows:
1. Figure out HR Reserve: HR Max(220- Age or Known) – HR Resting
2. Low HR Target = HR Rest + .8(HR Reserve)
3. High HR Target = HR Rest + .9(HR Reserve)
This should give you a good pace to shoot for during the race. We would suggest to test it out during a workout to see how these values feel and adjust accordingly.
A lot of times it is best to start conservatively in long races and build throughout the race to leave yourself energy for the end of the race.