By Rebecca Kurtz, CTS Expert Coach
Triathletes and runners are familiar with Fartlek intervals, but many reserve them for periods of the year that are closer to their goal races. They are often seen as race-specific or race-prep workouts, but they can also be used to build your energy systems. These intervals are above-threshold running intervals, so you will produce a lot of lactate throughout the course of the workout.
As such, they will help improve your body’s ability to process lactate quickly. That’s important because processing lactate is the key to increasing the pace you can maintain at lactate threshold. Fartlek runs can be done at a variety of intensities and durations, but because it’s early in the training year (at least in the Northern Hemisphere), during this phase of training we want the pace and heart rate to be above lactate threshold and faster than your goal race pace. Fartlek runs are also a great way to add speed back into your program if you have taken a couple of months off from speed work.
Why Do Speed Work Now?
There is a big misconception that the winter is the time for “long, slow miles”. While this can work for some athletes who have 25+ hours a week to train, for most of us who have full-time jobs and families, we need to make sure we are not spending a bunch of time going slow. To go fast in a race, you have to train fast.
It can be challenging to incorporate the high-intensity component into a 70.3 or Ironman plan, since in the few months leading into a race of such a distance, the focus is on developing power/pace at lactate threshold with longer rides and runs. Trying to increase both intensity and volume can be a recipe for disaster.
You either can’t complete each one sufficiently enough to provide a good adaptation, or you end up injured and highly fatigued. When there’s doubt about how to balance intensity and volume, many triathletes default to increasing volume and skipping intensity. Fartlek intervals during this early portion of the season helps to mitigate the conflict between the two later on.
Focus on Three Basic Areas of Training
Let’s get a little more technical for a bit. There are three basic areas that endurance athletes want to focus on throughout the year: your maximal aerobic capacity (VO2max), lactate threshold (glycolysis), and oxidative phosphorylation (base aerobic conditioning). If you have been training consistently for a couple of years, your oxidative system is fairly well developed, which means that time-crunched athletes can get away with spending a bit less time focusing on that system.
The two areas that will make a big difference in your 70.3 performance are VO2max and your glycolytic system. In 70.3 and Ironman racing, the number one limiter is your power/pace at lactate threshold. And although lactate threshold responds well to training, you also have to improve your performance at VO2max in order to maximize the improvements you can see at lactate threshold.
Think of it this way: there’s a gap between your performance at lactate threshold and your performance at VO2max. Focusing on lactate threshold training can move your power/pace at threshold closer to your power/pace at VO2max. Training your VO2max can give your performance at lactate threshold a bigger space to move up into. It “raises the ceiling”, so to speak.
While your VO2max number (the maximum amount of oxygen you can take in and use) is largely genetically determined and only somewhat trainable, the pace you can run at VO2max is much more trainable. And high-intensity running intervals are the key to improving the pace you can achieve at VO2max.
This will give your lactate threshold more room to move. And the reason you want to insert high-intensity running into your January and February training is because you will spend the summer months focusing on threshold training for the 70.3 distance. Before you get there, you need to make sure that you have room to increase that threshold so that you don’t see a plateau in fitness mid-season. Plus, the training necessary to improve your performance at VO2max also applies a training stimulus to all the energy systems below it (aerobic and glycolytic), so training at the high end helps improve performance at all other levels. Think of it as “a rising tide lifts all ships”.
Spend some time now working on above-threshold training. It will pay off in dividends on race day, especially when you are comfortably passing all of your competitors who did “slow miles” during the winter.
Warm up 10-15 minutes
Complete 6 x 20 second RunningStrides (RS) with 1 minute easy running between each
6×3 minute RunIntervals (RI) at as close to max heart rate as can be achieved. (RPE 9)
Recovery between intervals (RBI): 3 minutes easy running
Cool down 10 minutes easy.