A Moment on Intervals…

I have been thoroughly enjoying the Powerslide Powerskating Tutorials over the last couple of months.  The guys at Powerslide are doing some great educational videos to teach skaters about different elements of technique.  The framing of the tutorials is easy for everyone who is interested in skating to understand, but these tutorials are really focused on fitness and speed skaters who want to skate marathon events.

After the Chicagoland Inline Marathon this year, I heard a number of comments from skaters about how they needed to add more interval workouts to their training.  I totally agree and have been needing the same structure in my workouts, also.  Part of the problem is that this is a structured work out that really isn’t fun, and, realistically, we all skate because it is fun to go fast.  Intervals, though, are well worth the pain.  Bringing this post back to my comment about Powerslide’s Powerskating Tutorials, a recent installment was specifically about intervals:

This is a very basic explanation of intervals for skaters.  Simple is really the best option here.  There is a ton of sports science on intervals, and, honestly, all it does is add to the confusion.  Intervals, for work outs, should be simple:  go hard for a certain amount of time, go easy for a certain amount of time.  The question quickly becomes how long the intervals should be.  Different intervals will, in theory, accomplish different training goals.  Realistically, intervals help you get your heart rate up so you train at or above your VO2 Max, the goal of which is to increase your VO2 Max, thereby increasing your level of fitness.  Intervals are also important for racing because, in a good race, you will have to deal with a lot of attacks from the front, and chasing down a flyer, climbing a hill, or a finish sprint are basically work intervals.  Joe Friel (clearly one of my favorite sport science bloggers) had a recent post on a study from Norway about the different effect of interval duration on highly trained racing cyclists.  The results are compelling, but what was notable is that the test group who had shorter interval durations had bigger gains in their VO2 Max after 10 weeks of training.

The science is fun to read (for me at least), but what we really care about is:  1. Why bother doing intervals, and, 2. How long should they be?

There are two reasons inline skaters should be doing intervals.  First, it is one of the best ways to help build your VO2 Max, and basically get you in better cardiovascular condition.  Marathon outdoor racers participate in endurance events, at least in the sense that the race takes at least an hour to complete.  We need to be cardiovascularly fit.  However, any training plan that includes intervals should also include extended duration Zone 2 heart rate work, also.  The musculature used for speed skating are made up of reciprocal systems, and both need to be utilized to create a strong skater.  Intervals help build lactate threshold tolerance and VO2 Max by working fast twitch Type II fibers, but the slow twitch Type I fibers work to clear out that lactate during the rest intervals.  As a result, you need both to be stronger and faster.  So we do intervals to compliment all that mind numbing time on the bike or on the trail staying in HR Zone 2.  Second, it is the best kind of training that mimics racing we can get, not considering tempo/fartlek sessions, especially if you train solo.  All of the up and down of intervals help prepare you for the pack dynamic of a race.  Lets say you get stuck at the back of a long pace line of about 30 skaters at the NorthShore Inline Marathon and you get to that first really sharp feeling hill climb around mile 10 of the race.  The front of the line speeds up, the middle of the line lags, and pretty soon, you are looking at an accordion gap opening in front of you as the line pulls up the hill, potentially leaving you skating alone in no-man’s land.  The best way to make sure you have the gas in the tank and the power in your legs to race up that hill and stick with the line is to do intervals, because this is the kind of situation you will run into over and over again in race after race, especially races with hills like the Chicagoland.  Intervals allow you to train for this part of a race without actually being in a race during every training session.

The big thing to remember and consider when doing intervals is to stop immediately if you cannot maintain your technique.  Absent good technique, the exercise/drill is meaningless.

Now that we know why, the next step is to determine the best duration for intervals.  Friel’s post suggests shorter durations for work intervals, and even shorter duration rest intervals, something similar to 45 second work intervals and 30 second rest intervals.  He also points out, though, that these kinds of intervals work best for well trained athletes.  The rest of us mere mortals are better with a 1 to 1 interval duration ratio.  The Powerskating tutorial above suggests 1 minute by 1 minute intervals, and this is a great place to start.  This means skating hard for 60 seconds and skating easy for 60 seconds.  There are tons of permutations on these examples.  A recent favorite of mine is a 2 minute work interval followed by a 1 minute rest interval.  The better question when deciding on interval duration is deciding the kind of workout you are going for.  Different intervals will accomplish different things.  Readers of Barry Publow‘s book Speed On Skates will note he goes into great detail about the different types of intervals and what they will accomplish.  Publow has also added to the general skating knowledge-base on the issue of intervals, also.  His post on Inline Planet provides some explanation for the benefit of intervals and two sample work outs for intervals.

In my experience, there are three types:  Short intervals with very high intensity, equal duration intervals, and long duration intervals.  Short intervals at a high intensity are just that, 30 seconds or less at a pace that puts you at or near your max HR or max level of exertion.  These can be done in sets with a longer rest interval between sets or with shorter rest intervals.  These build your lactate threshold and lactate tolerance, and will help you when you are in the finish sprint with your legs burning and ready to give out from under you.  Equal duration intervals are, basically, the intervals discussed in the Powerskating video above.  They are great for helping build endurance generally.  Longer intervals at speed get you used to skating faster for longer periods so you can chase down a flyer in the middle of a race.  Intensity should vary based on duration.  Shorter duration work intervals usually mean higher intensity while longer work intervals usually mean less intensity during the interval.  However, generally, intensity for any interval should be above 80% max effort, or HR Zone 4.  My recent long intervals will have HR spikes above 160 bpm, where my shorter interval spikes will be closer to 170 bpm, if I can manage it.

Either way, it is clear that sport science suggests that interval training is an important part of training.  However, it is important to also note that while intervals are a necessary part of training, they should not be used to the exclusion of longer duration endurance work outs.  I have already started to think about what the off-season will look like for me, and what my macrocycle and microcycles will look like for training.  I will have more on that after the NorthShore Inline Marathon.

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