This is Part 2 of our series on How to Write Your Own Training Plan. You’ll find Part 1 here. Over the next 9 posts we’ll cover the following topics:
1. Intro
2. Definitions and Terminology (⭐You are here.)
3. Where You Are and Where You Want to Go
4. The Elements of a Training Cycle
5. Workout Purpose & Design - Endurance
6. Workout Purpose & Design - Threshold
7. Workout Purpose & Design - Speed & Hills
8. Putting it All Together - Micro, Meso, & Macrocycles
9. The Extras - Strength, Cross-Training, & Course-Specific Add-Ons
10. Taper & Race Prep
Before we delve into the nuances of workout structure, it’s important to define our terminology. While many of the terms used in training science are straightforward, others are a bit more nebulous. My intent here is to clarify how I’ll be using each term, as well as other usages, alternate names, and related concepts you might encounter from other sources. As much as possible, I’ll give you a more technical definition, a practical description, and some actionable information on how it applies to training.
I’ll continuously update this section as more topics are introduced, or based on your feedback, so if you have specific questions on a term or meaning, please reach out! In the meantime, please at least read the Paces and Workout Formats sections of this post—it will be critical to understand these terms and concepts as we begin to create a training plan. It would also be helpful to be familiar with the physiology terms at the outset, but you can also refer back here as they come up.
Paces
Easy Pace - Relaxed pace at which oxygen demands are easily met and energy production can come primarily from the oxidation of fat. Easy runs primarily stimulate systemic adaptations to the cardio-pulmonary system, improving blood flow and oxygen delivery to working muscles. Oxidative energy production and metabolism is also continually enhanced as easy volume is increased.
Easy pace is also often referred to as conversational pace, recovery pace, or endurance pace, and it’s the assumed pace for warm-ups and cool-downs, as well as the activity recovery portions of interval workouts, unless otherwise specified in the workout’s construction.
Purpose - Easy runs build endurance and time on feet with low systemic stress. These miles will make up the bulk of your running and lay the foundation for all other workouts and adaptations. They should feel truly easy, not just somewhere below hard. Easy pace is a range that should always be based on effort, and the actual speed will vary based on weather, fatigue, stress, etc.
Ways to assess your effort - Easy pace should be conversational. You should be able to say the whole Pledge of Allegiance or sing the chorus of a song without gasping. Another check is whether you can breathe through just your nose. I don’t generally love heart rate as a metric, but if you’re so inclined, it should be a Zone 2 effort.
Speedwork - Structured workouts that usually involve repeated efforts at speeds that are only sustainable from roughly 1-10 minutes. These runs utilize muscle fibers capable of producing greater force and power than those typically used for easy miles. Speed workouts provide a range of benefits and adaptations depending on their structure, but generally they impart higher intensity stresses to the aerobic system by creating a high demand for oxygen, and stimulate adaptations at the muscle cell to improve efficient force output and energy production. Speedwork is almost always formatted as repeated alternating intervals of work and active recovery (or full rest), which allows more time to be spent at high intensity than a continuous effort would.
Purpose - Speedwork improves neuromuscular recruitment of muscle fibers, making fibers more efficient at working together so that force can be produced with less energy cost. Speed workouts can be used to improve top-end speed, or to become more aerobically efficient at slower speeds. Of all the workout formats, speedwork generally requires the greatest recovery time of up to 48 hours.
Appropriate Effort - Speedwork should feel hard–sometimes very hard–but never out of control. You should be able to say only a few words--"pace okay?" but not a full sentence. Because speedwork puts a large amount of stress on bones and tissues, it should not be done on excessively tired legs due to the risk of injury. When doing speed repeats you should generally finish the set feeling tired, but like you could do one more rep if you had to. Heart rate is a difficult metric for speedwork, as it lags as an indicator and isn’t useful at all for shorter reps.
Threshold - The pace that corresponds to the very top end of your aerobic endurance zone. Threshold is the fastest pace at which your body can sustainably produce energy and manage the byproducts of energy production that cause rapid muscle fatigue. Below threshold pace, the body’s oxidative energy production capabilities exceed demand, and muscle cells can work efficiently while maintaining homeostasis. Above this pace, working muscles become increasingly reliant on the fast production of energy by fermenting glycogen (stored carbohydrate) without oxygen, a method which is much quicker, but less fuel-efficient than the oxidative process. The reaction leaves behind hydrogen ions that create acidic conditions within the cell. Accumulation of these ions eventually interferes with muscle function and causes the burning sensation felt at higher intensities as muscles fatigue and lose power.
Practically speaking, threshold is the pace you could maintain for 50-60 minutes. Threshold workouts attempt to maintain a steady state at, or just below, the threshold for a sustained period.
Threshold is also often referred to as anaerobic threshold (AT), lactate threshold (LT), and LT2. Some training plans and coaches use threshold interchangeably with tempo pace, though others use tempo more broadly.
Purpose - Threshold workouts primarily operate at the muscle cell level to improve how energy is produced and how efficiently byproducts are cleared. Over time, these workouts increase the pace at which homeostasis can be maintained, allowing a runner to sustain faster paces for longer.
Appropriate Effort - Threshold is a physiological state and a pace you should learn to feel, as it represents the line between sustainable and unsustainable effort. At threshold, you should still be able to talk, but only in short sentences. Once you're running faster than threshold pace, your breathing will quickly become more rapid and feelings of discomfort shift towards pain. Depending on how far over threshold you are, the pace and associated systemic stresses can be sustained for anywhere from seconds to miles. As with easy pace, the actual speed when threshold occurs will vary with weather, fatigue, etc.
Tempo - A somewhat nebulous term that can specifically refer to threshold pace, or any pace that’s harder than easy pace and easier than threshold. Some coaches and plans also use it to refer to any workout that prescribes a defined pace that is sustained for an extended distance or time. (The pace could be marathon pace, threshold, half pace, etc.) I tend to avoid use of the term tempo altogether due to its ambiguity, but if you see it in a plan or are working with a coach, make sure you understand how they define it.
Race Pace / Goal Pace - Anticipated pace for the goal event.
Date Pace - Some plans prescribe workouts at the pace at which you’d run that distance today, as opposed to the pace at which you hope to run on race day. Date pace would theoretically shift over the course of the training cycle so that by race day, it’s the same as race pace.
Workout Formats
Intervals - Defined periods of greater effort, followed by a defined recovery or rest. Intervals can be set by time or distance, and recovery periods can be active (running or walking), or full standing rest.
Purpose - Alternating work and rest periods facilitates the ability to accumulate more time at high intensity. During recovery periods, the intensity is decreased enough that the oxidative system can clear waste products and stabilize the environment within working muscles. In some cases, the work portion of the interval is really to set the stage for the desired aerobic adaptations to be stimulated during the recovery interval.
While intervals are most often associated with speedwork, any pace can be administered in an interval format.
Hill Repeats - A form of interval training in which the work interval is running uphill (or sometimes down) for specified times or distances.
Purpose - Improves strength, form, and efficiency. Hill reps are also one of the most effective workouts for improving cardiac stroke volume, which is a major contributor to VO2max
Progression Run - Run which starts at an easy or slower speed and increases in pace through the duration of the run. Fast finish runs are a form of progression run where the speed increase is concentrated in the final miles.
Purpose - Progression runs develop speed endurance by increasing the stress on the body as fatigue increases. They’re a good way to practice negative-splitting, as they require holding pace back early in a run
Positive Split - Generally referring to race strategy or performance, positive splitting is running the first half of a race faster than the second. Unless the course is MUCH easier in the first half than the second, this is not the recommended strategy.
Negative Split - Running the first half of a race slower than the second half. For all race distances greater than 800 meters, this is nearly always the optimum strategy.
Strides - Fast (usually short) intervals added to an easy run for the purpose of incorporating quick speedwork in a low-stress format. Strides are a good way of maintaining speed in parts of the training cycle focused on other areas of fitness, and also offer a nice change of pace, range of motion, and biomechanics within slower easy runs. A common format for strides is 6x30 seconds, 4x100m, etc. Strides can also be given as hill strides, which are short hill repeats with a similar function and purpose.
Fartlek - Unstructured speed sessions that incorporate a range of paces and interval lengths. These are often done by feel and without any predetermined format, or they can take on an organic organization, like running hard for 30 seconds every time you see a blue car, large dog, etc.
Warm-Up - Easy miles intended to increase blood flow, warm muscles and tendons, and reach an aerobic steady state before beginning the more intense portion of a workout. Warm-ups have been shown to improve performance and lower perceived effort during harder efforts, so don’t skip them!
Cool-Down - Easy miles at the end of a workout that provide time for heart rate to decrease and that facilitate oxygenation and waste removal from muscles. While active recovery does speed the return to homeostasis at the muscle cell level, cool-downs have not been shown to reduce soreness or improve recovery time overall.The more important benefit to cool-downs may be that they help your body transition from the workout to a recovery state.
Physiology
Aerobic Energy Production - The process of converting stored energy in the form of fat (lipids), or pyruvate or lactate (carbohydrates) through a series of redox reactions (i.e. utilizing oxygen) into chemical energy that powers mechanical movement. Aerobic energy production yields more usable energy per molecule of fuel than anaerobic production, but it also takes much longer. Aerobic processes are generally sustainable for very long periods, and cells remain in homeostasis when energy is produced through these channels.
Anaerobic Energy Production - The process of creating chemical energy from stored glycogen by fermentation without the presence of oxygen. Anaerobic energy production is about 100 times faster than its aerobic counterpart and does not directly increase oxygen demand, but it produces significantly less energy per molecule than the aerobic process. The anaerobic fermentation process leaves behind 2 lactate molecules, which can be further metabolized through aerobic processes (if oxidative capacity is available) as well as positively charged hydrogen ions. It is these ions, and not lactate, that eventually leads to an acidic state within the muscle cell that contributes to fatigue. Anaerobic energy production is also called anaerobic glycolysis.
Mitochondria - Organelles within muscle fibers that use oxygen to convert fat (lipids) or sugar (glycogen or lactate) into chemical energy that can in turn be converted into the mechanical energy of movement.
Slow Twitch Muscle Fiber - (also called Type I, ST, or red fiber) Muscle fibers characterized by a dense network of capillaries that deliver oxygenated blood to the mitochondria. ST fibers are generally smaller and have lower contractile force than their fast twitch counterparts, but they can utilize a wider variety of fuel sources and fatigue more slowly.
Fast Twitch Muscle Fiber - (also called Type II, FT, or white fiber) Muscle Fibers with fewer or no mitochondria that are more reliant on anaerobic energy production. Energy is produced very rapidly, but is limited by available carb stores. Due to the less efficient nature of anaerobic metabolism and accompanying rapid accumulation of byproducts, these fibers tire quickly and require more time to return to homeostasis than ST fiber. FT fiber exists on a spectrum from completely anaerobic to “hybrid fiber,” which has characteristics of fast twitch fiber but also has high mitochondrial density. Hybrid fiber in particular is influenced by training modality and can become more oxidative over time.
VO2max - The maximum volume of oxygen your body is capable of utilizing in a given amount of time. VO2max is usually measured in liters of oxygen per minute, or liters per minute per kilogram, which normalizes across body mass. A high VO2max indicates that a runner has the capacity to produce a large amount of energy through aerobic processes.
vVO2max - The pace at which a runner reaches their maximum oxygen utilization. For most runners, it will be somewhere around 3K race pace. Workouts at or near this pace maximally stress the aerobic energy system by working it at full capacity.
Glycogen - The form of carbohydrate that sugar takes when it is stored in muscles and liver tissue. When a runner carb-loads, they are topping off glycogen stores. Bonking occurs when glycogen stores in working muscles are depleted. For the most part, glycogen is only useful within the muscles in which it is stored. While glycogen from the liver does get released into the bloodstream and can be moved to working muscles, this is a small part of overall glycogen metabolism.
Lactate - form of sugar molecule that is left after anaerobic fermentation occurs. Lactate (unlike glycogen) can be shuttled between working muscles, facilitating more efficient energy utilization. Lactate is a product of anaerobic metabolism, and can be transported in the bloodstream to muscle fibers with available aerobic capacity, where it is used to fuel further aerobic energy production. Lactate is a versatile fuel and signalling molecule and NOT responsible for muscle soreness or ‘the burn.’
Heart Rate (HR) Zones - Usually a 5-zone division between resting heart rate and maximum heart rate. While HR is certainly correlated to effort, it can be a difficult data point to accurately assess in real time. I would support its use as a guide for effort on easy runs, and potentially for sustained efforts at or below threshold, but its utility for speed or anything in a short interval format is limited. If you do intend to use heart rate zones as a training metric, I would highly recommend performing a HRmax test rather than relying on a calculation. Pfitzinger’s method is fairly easy to do: run 3 hard repeats up a 400-600m hill and recover down. Your heart rate on the last one should be at or very close to your max heart rate.
