All Systems Count

If you’ve been following my newsletter you’ll know that I am a proponent of speed and anaerobic work even for endurance athletes. Nevertheless, I still get questions on why, and how to incorporate it, so I’ll dig a little deeper.

Firstly, it is good to keep in mind that all energy systems (aerobic, lactic and ATP-CP) overlap and complement each other - they are not stand-alone systems. Similarly, muscle fiber recruitment and utilization work along a continuum. All systems are in play to some extent at any effort level.

Secondly, it is key to internalize that your 60-minute pace/power can not be higher than your 45-minute pace/power which can not be higher than your 30-minute pace/power, and then continue that logic until you get into the realm of seconds. So your marathon pace is limited by your half marathon pace. Your half marathon pace is limited by your 10k pace. Your 10k pace is limited by your 5k pace. Your 5k pace is limited by your 3k pace. Your 3k pace is limited by your 1500m pace. Your 1500m pace is limited by your 400m pace, etc.  Sorry to go on, but it’s important to make this point! Elite marathon runners could still knock out a 400m rep in sub-60 seconds if they had to.

Now take a look at the diagram above. If you are like most distance-focused runners you will have trained with the rather limited range of intensities on the right of the graph but you very rarely target the intensities on the left side - these are the intensities beyond your VO2 Max. As these stimuli have not been exploited, I hypothesize that adding this anaerobic adaptation and speed direction to your program will have a significant positive impact. There’s also the added benefit that it doesn’t require much at all. For an overview of training zones see Run Intensity Zones.

Outside the ranks of top racers, the layman endurance cultural premium on aerobic capacity means that the development of anaerobic capacity is often overlooked. Researchers at Georgia State University found that individual differences in anaerobic capacity explained 31 percent of the differences in 5K running times.

Anaerobic Endurance for Aerobic Conditioning

Anaerobic endurance training focuses on the physiological improvements in the muscles’ ability to endure force output through both neural and metabolic mechanisms. System efficiency is best demonstrated during prolonged stress upon the anaerobic system which in turn is highly dependent on the interaction of the aerobic system. 

Ways that Anaerobic Training Helps Endurance Runners:

1. Improved Muscle Function

   • Increase Glycogen Stores

   • Tolerate Lactate Build Up

2. Increased Running Performance

   • Boost Running Economy

   • Quicken Foot Speed

   • Reduce Ground Contact

3. Reduced Injuries

   • Strengthen Muscles and Joints

   • Enhance Resilience

The last category is worth discussing as I quite often get push-back on joining my interval sessions based on a perception of injury risk.

There is no doubt that running injuries are unfortunately far too common. Gordo Bryn nicely puts it:

• Running at ANY speed is stressful.

• Running easy? Stressful.

• Running slowly? Still stressful.

• Overuse injuries take weeks to manifest.

So before adding intensity or additional duration to your runs make sure:

• You’ve established frequency - At least 4 runs per week

  • Easy runs Z1 to Z2

  • Keep duration conservative

• You’ve proven your biomechanics - 6 months injury-free

  • You’ve worked on running form

  • You’ve worked on strengthening your kinetic chain; start with foot strength and work your way up. See Ode to Stability.

With that in the bag, you are ready to slowly progress stimulus at both ends of the spectrum. Lengthening easy runs and adding speed work.

If you have a weakness that could manifest itself during a high-intensity interval, then let’s address that weakness. Ignoring it isn’t a good idea. As something that might fail at 10 seconds at 150% of Critical Power is also a weakness that may manifest itself at 2hrs at 90% or 6 hours at 60%. 

It might sound counterintuitive but coach Brad Hudson deliberately prescribes short hill sprints to any of the athletes he deems as being injury-prone.

As Jason Karp points out in his book The Endurance of Speed, research studies have found sprinting and distance running performance to be significantly correlated; including between a 300-meter sprint time and a 10k run time, between 100-meter and 400-meter sprint times and 5k and 10k run times, and even between a 50 meter sprint time and a 10k run time. Among a group of athletes whose 10k times ranged from 32:37 and 56:21 a 300-meter sprint explained most of the variance in 10k times between runners.

Now you will notice that I am performance-oriented in this thesis. So let’s define performance as improvements towards your biological potential. I also realize that some of you are not focused on moving that marker. If you run for other reasons; community, an experience in nature, doing what you enjoy, and if so focusing purely on the endurance side “train don’t strain” is fine. For the rest of you, you’ll need the occasional time when to use a phrase Coach Stewart coined, you’ll need to have a “see God” moment.

Note that I didn’t include general health in the list of reasons to focus solely on the endurance side. Conversely, if true health benefits are the driver then you should almost certainly factor in anaerobic speed, strength, and other training modalities into your program. The evidence for the benefits of high-intensity training is overwhelming - pure run cardio is not the optimal approach for holistic health.

The stimulus necessary to build a robust body; mentally, physically, hormonally, neuronally, and metabolically is higher than most think. There is always a trade-off between the stress required to induce sufficient stimulus. Stress, when it comes to running, can be viewed as an equation, stress = volume x intensity. The stimulus is not linearly correlated to intensity, it is exponential. This means we can get the same health stimulus to create the beneficial effects of movement by moving harder (intensity) with way less volume (time). 

Another thing to keep in mind is that the stimuli from movement create a plethora of beneficial effects. A lot of these effects require the intensity to be, well, intense. If we never go hard enough we will not get the entirety of the benefits from movement. 

• Increased muscle mass

• Increased joint strength and stability

• Increase bone health

• Increased function of the immune system

• Increased function of the brain

• Increased metabolic rate (how much you burn at rest)

Now back to run performance gains. In summary, there are several reasons to train speed first for long-distance races.

1) It ensures that the training becomes more specific as the race approaches. Easy long runs, threshold runs, marathon-pace runs, and higher overall mileage are more distance-race-specific than VO₂max interval workouts and anaerobic speedwork.

2) Speed-first training gives you an increased speed reserve, increasing the potential pacing ceiling for any longer duration event.

3) A speed-first approach recognizes that VO₂max and related physiological markers increase with anaerobic training and that these should be maximized before training the fraction that can be sustained for a targeted race distance.