Sprint Intensity explained

Is a 30 second effort really an interval? Our answer here at NTS is yes. These short duration, high intensity interval sessions have become a staple of cross-country skiers around the World because they allow athlete's to log their interval time at a higher speed than during longer duration intervals.

Did you know, that not all 30 second interval sessions are the same? In general, there are two very different forms of 30 second intervals.

30 on 30 off – Performing a short effort with short rest turns an interval session into more of a ‘steady state’ session. These sessions can be done in L3 or L4 or some kind of combination of the two. A common threshold session is to do 30 on 30 off for 20 minutes, x2-3 sets (we will have some of these on the schedule later this fall) 

30 on with 1 min+ off – Short efforts with longer rest turn a 30 second interval session into a ‘sprint intensity’. Distance skiers and sprinters both need to learn how to be relaxed and efficient at high speeds. These sessions focus on L4 intensity but split the daily on-time into 30 second chucks. A great way for athletes to log quality L4 while at altitude or focus on higher speed L4 at sea level. 

Throughout the summer and Fall here NTS will recommend 30 second to 90 second sprint intensity intervals often to work on ‘leg speed’ aka having the comfort level and technique to move quickly. Track and field runners have used this strategy for a long time.10k, 5k, and marathon runners will use leg speed workout on a regular basis to train a pace that is just a touch above their racing speed. A 30 second interval session is designed to have the same effect on skis. 

Sprint intervals will become more frequent in the fall but even now is a great time of year to incorporate a 30 second interval session into your training week. I think these sessions are super fun and if they are done correctly shouldn’t be a devastatingly hard workout so it can be a great option to add in as a third intensity for the week.  

Heart rate monitors can be used during these sessions, but it is definitely not a crucial element of the workout. 30 second intervals are so short that it becomes kind of a mix between L2, L3 and L4 so even categorizing these sessions in a training log can seem strange. The bottom line and most important thing is to just focus on FEEL during these workouts. The pace should feel slower than a sprint-speed but faster than your average race pace. Generally we will explain the pacing goal of the session beforehand and log on-time according to the recommended intensity and duration. 3x8x30 seconds L4 sprint intensity = 12 min L4 

Want to train a faster sprint race qualification speed? This is the perfect workout. I like to think about breaking up a sprint course into 8 different sections. The perceived effort of each interval should be similar to a 3-4-minute sprint race, NOT that of an all-out speed effort. Skiers that become better at distinguishing the difference between all-out speed and 30 second ‘leg speed’ with become much better sprinters. It helps train relaxation at high speeds. 

Can be done on rollerskis, bounding, or on snow. For rollerski and snow sessions look for a mix of flats and up hills. 

Warm up like you would for a L4 session:

15 minutes L1

5 minutes L2

A few pick-ups to threshold 

Dynamic Stretching  

(if you can set a timer on your watch to go off every 30 seconds that’s great, if not I usually just mark out lines on the road or trail) You can do them continuously down the trail or back and forth on one section. 

Since the intervals are supposed to feel like running leg speeds I try to find terrain that is rolling and fast. This will help practice a fast but relaxed tempo and keep the legs from flooding with too much lactate.

The goal of this workout is to train the body to move quickly. Physiologically we are training the body to shirt between aerobic and anaerobic systems and to use lactic acid as a fuel source.  Technique focus is critical. 

This session is great at teaching the body to recover quickly between bouts, so it is beneficial for distance skiers and sprinters. You will notice that slow-twitch distance-oriented skiers will have a much easier time recovering between each 30 second interval because they are likely not generating as much lactate as fast twitch skiers. One of our goals is to get better at recovering between each interval. 

Doing the intervals solo can be a great opportunity to work on technique cues and fluid skiing, doing the intervals in groups is a great way to practice relaxed sprint style skiing in packs.