Why Speed and Endurance Training Cannot Be Mixed

Like most, I love cake. Given the opportunity, I would probably have it every day. At the same time, I love bourbon. If it were feasible, I would probably have it every day as well. From a health perspective, the combination of cake and bourbon – taken with any degree of frequency – would be disastrous. Both are sources of sugar, both create lethargy, both strain the digestive system. Even alternating between cake on Monday and bourbon on Tuesday throughout the week overloads the digestive and immune systems, severely hampering training and damaging health.

That may seem obvious to you. It may seem ridiculous to consider having either cake or bourbon every day of the week. It may seem outrageous to have dessert or alcohol in large quantities on most days of the week, then expect to be healthy or lean in the long term.

athlete throws medicine ball
2-time AFM Fittest age group winner — not endurance training.

But as an athlete, you are probably making exactly this mistake when combining training for speed and endurance. The Problem: unlike cake and bourbon, this combination doesn’t just overload your body…one quality diminishes the other and the combination overloads your body!

You can’t have it all at once. Speed training and endurance training are not complementary. Let’s explore why.


What is speed training?

For the purposes of running in a straight line, speed training is learning to put large forces into the ground via your feet. Not just large, but enormous. Not just enormous, but the absolute greatest forces of which you are physically capable. Beyond that, speed training is learning to create those maximal forces in 0.08 to 0.12 seconds, twenty or thirty or forty-four times in sequence. It is training extraordinary brain-to-muscle coordination through large ranges of motion.

Speed training requires short work intervals – frequently less than six seconds – and long rest intervals – frequently longer than three minutes – and mechanically perfect postures in order to use all that force. The intensity of every stride, of every rep, and of every day of speed training is near the limit of your capabilities. The brain is operating near capacity to keep your coordination together while trying to apply maximal forces. After proper speed training, both brain and body need time to recover, if there is any hope for you to train speed again.(1)

athlete marches with hands on wall
Ultimate player practicing acceleration posture — not endurance training.


What is endurance training?

For the purposes of field sports, endurance training should be learning to sustain maximum and near-maximum effort for the duration of a play, a game, or a tournament. Most athletes, however, treat endurance training as learning to “grind,” “fight,” or “tough it out.” Most athletes perform endurance training as if sporting success depends not on speed, power, technique, or strategy, but on continuous heavy breathing and accumulated acid in their muscles.

For any athlete in a field sport, it is bizarre to imagine how the following could help you run faster, jump higher, or play harder: five-mile runs; four-hour bike rides; 100-rep squat challenges; lifting light weights in a circuit class until your muscles ache.

In the future, we will discuss proper endurance training for field sports (what I call “conditioning”). For now, recognize that speed & power athletes are using endurance training the way marathoners and triathletes use endurance training – to improve the ability to do low-intensity tasks for long periods of time.(2) This sort of endurance training demands efficiency. Your brain wants to conserve energy. Efficiency means minimizing ranges of motion, minimizing forces produced, and minimizing oxygen consumed. Your brain is creating pathways of “do less.”

athlete lunges with kettlebells
Triathlete who set 2 PRs & completed 1st half-IM — not endurance training.


The Problem, restated: if you train speed and work on maximum range of motion, maximum force production, maximum involvement from your brain, endurance training is completely opposite to your goal of running faster!

To do equal parts of both in every week – speed day, endurance day, speed day, endurance day, speed day, endurance day – is to demand of your brain, simultaneously: “More force! More power! More flexibility!” and “Less force! Less power! Less flexibility!”

This is our “cake + bourbon” problem.

But there’s more to this story.


The Problem, explored: there isn’t enough time in the week to train speed and endurance to full effect.

Speed training requires thorough warm-ups and long rest periods. Speed training is a 60- to 90-minute endeavor. Nearly all great track & field coaches acknowledge that you need at least one full day of rest between speed training sessions. There are flexibility demands to be met during those rest days, typically 30- or 45-minutes of soft tissue work and stretching. Pulling out all the stops, speed development and its accessory work require five or six training hours from your week.

Training like an endurance athlete is a “more work” process. To gain more endurance, 30-minute runs need to become 60-minute runs; two bike rides each week need to become four bike rides each week; 100 squats need to become 200 squats. The time demands of endurance training grow linearly, because you have to keep increasing the amount of work you do. Pulling out all the stops, endurance development requires six to ten training hours from your week.

ATX Speed and Strength serves athletes who want athletic excellence and have real lives to manage. I do not coach athletes with 11 to 16 hours available to train. You are not an athlete with enough free time to make training a part-time job in addition to your full-time job and full-time family.

But there is still more to this story!

athlete performs agility drill on turf
World-class ultimate player — not endurance training.


The Problem, explored further: combining speed and endurance training breaks down your body.

While the body recovers from speed training, connective tissues are being rebuilt. The soles of your feet, your Achilles tendons, the tendons of your hamstrings and glutes, and the tissue which binds your abdominal muscles together all need water, salts, nutrients, circulation, and time for repair.

Endurance training involves asking those same tissues to do more work!

Literally, you are telling your body with every jogging step and every pedal stroke to STOP repairing and rebuilding. To combine speed training with long-course endurance training is to create a strongly negative load on your immune and hormone systems.

You can’t have it all. Not at once.

This article raises several questions to be explored more deeply:

  • What if speed training and endurance training are not done in equal parts each week?
  • What is the “minimum effective dose” for speed training and endurance training, instead of “pulling out all the stops”?
  • How should I condition for rugby, ultimate, or soccer?
  • How can I have it all not at once?

In my next article, How to Get in Shape (for Your Sport), we will solve The Problem.

For now, you have to make a decision:

Is it more important to you to have cake or bourbon?


  1. This is not limited to straight-line running. Agility, throwing power, jumping ability, strength training, and technical skill work all follow the same principles.
  2. Observe the training of great endurance athletes, from half-mile runners (can you run three sub-60 400s?) to Olympic triathletes. They incorporate speed training, power development, and generous rest time into their week. This discussion of endurance training refers to amateurs, who frequently are severely misguided.

1 thought on “Why Speed and Endurance Training Cannot Be Mixed”

  1. I want to make sure that I do the right workout procedure. It makes sense that I would want to not mix speed and endurance training! I’ll do my best to get good speed training and not mix it with endurance.

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