Fatigue Management, Simplified: Here’s a Better Way to Track
Verro Fatigue Calculator
Key Points
Fatigue is more than just “feeling tired”. It's measurable and trainable. Understanding fatigability helps athletes structure smarter, more sustainable training plans.
You don’t need a lab or expensive tools to estimate fatigue. With just sets, reps, RPE, and a basic understanding of movement types, you can get meaningful insight into how taxing a session really is.
Some exercises are inherently more fatiguing than others. Heavy compound lifts like squats and deadlifts generate more systemic fatigue than isolation movements like curls or triceps extensions.
A simple Fatiguability Score formula can help regulate training intensity. This score helps you balance load, plan recovery, and prevent burnout or overreaching across the training week.Introduction: Why Understanding Fatigue Matters More as You Advance
Introduction: Why Understanding Fatigue Matters More as You Advance
As you progress in your training journey, understanding fatigue becomes less of a luxury and more of a necessity. For beginner lifters, almost anything works—progress comes easily, recovery happens fast, and fatigue rarely outpaces adaptation. But as you become stronger, train more frequently, and push closer to your limits, managing fatigue becomes a critical skill. Get it wrong, and you’re looking at stalled progress, nagging injuries, or outright burnout.
The challenge is that fatigue is surprisingly hard to track. It’s not a single metric you can measure with a stopwatch or a scale. Instead, it's a blend of muscular stress, nervous system load, psychological strain, and metabolic disruption, all of which respond differently to training variables. Elite athletes often rely on expensive lab testing, wearable tech, or a team of coaches monitoring HRV, bar velocity, lactate, and more.
Most of us don’t have that, so that’s where this blog comes in. The goal here is to give you a practical, scalable method for estimating and tracking fatiguability…that is, how quickly and severely a given training session induces fatigue—using sets, reps, RPE, exercise type, and frequency as our variables.
With these variables, we’ll show you how to approximate the fatigue cost of different exercises, monitor trends across your training cycle, and make smarter programming decisions, all without a lab or spreadsheet overload.
The Science Behind Fatiguability
As you advance in training, understanding fatigue becomes more than just a feeling, it becomes a variable worth tracking. In sports science, fatigue is now understood as a symptom, while fatigability is the rate and magnitude of performance decline or perceived effort increase in response to a task (Enoka & Duchateau, 2016). This dual definition gives us two lenses:
Performance fatigability: the objective drop in output — like decreased bar speed, power, or reps completed.
Perceived fatigability: the internal experience of rising exertion, even when output remains steady.
These branches are driven by overlapping systems:
Neuromuscular fatigue occurs when your nervous system struggles to fully recruit muscles under load, particularly as high-intensity or repeated efforts accumulate (Taylor et al., 2016).
Metabolic fatigue results from the accumulation of byproducts like hydrogen ions (H⁺) and inorganic phosphate (Pi) that impair muscle contractility and efficiency (Hargreaves, 2016).
Psychological/central fatigue involves mental strain and changes in neurotransmitters, which increase the perception of effort and can reduce voluntary drive to the muscles (Tornero-Aguilera et al., 2022). Fatigue can also be categorized by where it manifests:
Local fatigue (e.g., biceps during curls) is mostly muscular and peripheral.
Systemic fatigue (e.g., full-body drain after heavy squats) reflects cardiovascular, hormonal, and central nervous system strain.
And while research often quantifies fatigue using EMG, lactate readings, or jump force platforms, most of us don’t need a lab. Training data like RPE, sets, reps, and bar speed offer reliable proxies that closely mirror lab findings in real-world training contexts (Pareja-Blanco et al., 2017).
The Four Key Variables That Drive Fatigability
Tracking fatigue doesn’t always have to require a force plate, lactate monitor, or wearable. Thanks to decades of research, we can reasonably estimate an exercise’s fatigability using four core training variables, all of which should be a part of most lifters' logs.
Here are the four pillars that influence how much fatigue a given movement produces:
1. Exercise Type
Not all exercises stress the body equally. Compound, multi-joint lifts (like squats or deadlifts) recruit more muscle mass, load the spine, elevate heart rate, and produce more systemic fatigue compared to single-joint or machine-based movements (Hargreaves, 2016; NSCA, 2016). Lower-body exercises tend to create more fatigue than upper-body ones due to larger muscle mass and oxygen demand (Taylor et al., 2016).
For example, a set of 12-rep squats may spike heart rate and nervous system fatigue, while a similar set of leg extensions mostly induces localized quadriceps fatigue.
2. Sets × Reps = Volume Load
Volume determines the accumulated work, and higher volume generally means more metabolic fatigue, especially if rest is short. Repetitions performed closer to failure (especially with high RPE) are disproportionately fatiguing (Pareja-Blanco et al., 2017). In studies on velocity loss and metabolic stress, total volume was a major predictor of post-workout fatigue markers like lactate accumulation and reduced jump performance.
3. RPE (Rate of Perceived Exertion)
RPE is more than just a subjective number. RPE maps tightly to both performance and perceived fatigability. Training to RPE 9–10 (1–0 reps in reserve) results in higher neuromuscular fatigue, longer recovery times, and in many cases, diminishing returns compared to submaximal sets (Enoka & Duchateau, 2016; Stronger By Science, 2025).
Research shows that avoiding failure (e.g., stopping at RPE 7–8) can reduce fatigue by up to 50%, while still producing gains in strength and hypertrophy.
4. Fatigue Coefficient (EFC)
This is the “X factor”, a multiplier based on how inherently fatiguing the exercise is. Compound lifts, especially those performed under load or with high technical demand, have higher EFCs due to their whole-body strain. Isolation movements and mobility drills have much lower coefficients.
This concept draws on findings from both empirical research (Pareja-Blanco et al., 2017) and applied coaching practice (Tuchscherer, 2016; NSCA, 2016), where bar speed, RPE, and rep drop-off are used to classify movements by fatigue impact.
Together, these four variables give us a data-informed way to estimate how fatiguing any session or exercise is likely to be. Next, we’ll show you how to plug them into a simple formula to generate a fatigability score you can track over time.
A Practical Formula for Estimating Fatigability
If you could predict how fatiguing a training session is before you even touch a barbell, it would change the way you program forever. That’s the goal of this section: to give you a simple, research-informed equation to estimate how much fatigue any exercise is likely to generate using only sets, reps, RPE, and the type of movement.
This formula is inspired by models like Mike Tuchscherer’s fatigue percentages for autoregulation (Tuchscherer, 2016), as well as empirical research on barbell velocity loss, session RPE, and training-to-failure studies (Pareja-Blanco et al., 2017; Nuckols & Wolf, 2025). After evaluating how high-rep sets were disproportionately scored in earlier models, we’ve revised the formula to better match real-world fatigue perception and recovery costs.
The Verro Fatigue Formula
Fatigue Score = Sets × (Reps ^ 0.65) × (RPE / 10) × EFCSets: The total number of sets performed.
Reps^0.65: A non-linear adjustment to repetition count that better reflects real-world fatigue curves. This reduces the disproportionate impact of very high reps while still honoring the role of volume.
RPE/10: Normalizes effort on a 0–10 scale. The closer you train to failure, the more fatigue accumulates (Enoka & Duchateau, 2016).
Exercise Fatigue Coefficient (EFC): A multiplier based on how inherently fatiguing the movement is — determined by muscle mass involved, systemic load, complexity, and recovery demand.
This gives us a fatiguability score: a raw number that can help compare sessions, plan training weeks, and guide recovery strategies.
Example Walkthrough
Let’s revisit our earlier comparison using the updated formula:
Example 1: Back Squat
Sets: 4
Reps: 8
RPE: 9
EFC: 1.4
Fatigue Score = 4 × (8^0.65) × (9/10) × 1.4 ≈ 30.2
Example 2: Barbell Curl
Sets: 3
Reps: 12
RPE: 8
EFC: 0.7
Fatigue Score = 3 × (12^0.65) × (8/10) × 0.7 ≈ 15.3
This formula gives more proportionate scores while still preserving intuitive insight: squats still induce far more systemic and neuromuscular fatigue than biceps curls, but the rep count doesn't skew the fatigue too high when isolation exercises are done for moderate volume.
How to Use the Scores
| Score Range | Fatiguability Level | Meaning |
|---|---|---|
| 0–15 | Low | Light isolation work, skill drills, mobility; minimal systemic fatigue. |
| 15–30 | Moderate | Sustainable strength or hypertrophy work; most upper-body compounds and moderate lower-body movements. |
| 30–45 | High | Fatiguing compound lifts; heavy lower-body work; limit frequency or increase recovery. |
| 45+ | Very High | Maximal systemic fatigue; heavy squats, deadlifts, or high-effort barbell work; use sparingly or before deload/taper. |
You can track weekly average scores or flag individual sessions where scores creep up. This could be a sign you may need to pull back to recover or switch training blocks.
Assigning Fatigue Coefficients (EFCs)
The Exercise Fatigue Coefficient (EFC) is the multiplier in our fatiguability formula that accounts for how inherently fatiguing a movement is, beyond just volume or RPE. Think of it as a rating for how “expensive” an exercise is in terms of systemic and local fatigue.
This concept draws on both scientific research and coaching practice, where it’s widely recognized that not all lifts impose the same recovery cost, even with matched volume and intensity (NSCA, 2016; Tuchscherer, 2016; Pareja-Blanco et al., 2017).
What Influences an Exercise’s Fatigue Coefficient?
Several factors drive an exercise’s EFC:
Muscle Mass Involved: The more muscle groups engaged (e.g., squats vs. curls), the higher the metabolic and neuromuscular strain (Hargreaves, 2016).
Joint Complexity: Multi-joint movements like deadlifts involve greater coordination and motor unit demand, increasing central fatigue.
Systemic Stress: Exercises that elevate heart rate and respiration (e.g., compound lifts, HIIT) impose higher cardiovascular and neural fatigue loads (Taylor et al., 2016).
Stability & Load: Free-weight and axial-loaded movements create more proprioceptive and spinal loading stress.
Fatigue Coefficient Table
Below is a working reference table for assigning EFCs to common exercise categories. These are approximations based on current literature and field data. You can refine them for your own training or client needs.
| Exercise Type | Fatigue Coefficient (EFC) |
|---|---|
| Compound Lower Body | 1.3-1.5 |
| Compound Upper Body | 1-1.2 |
| Isolation Lower Body | 0.8-1 |
| Isolation Upper Body | 0.6-0.8 |
| Mobility / Skill Drills | 0.3 – 0.5 |
Example Application
Back Squat: EFC: ~1.4 (very high systemic load)
Romanian Deadlift: EFC: ~1.3 (hip-dominant, high load)
Leg Curl Machine: EFC: ~0.9 (single-joint, moderate local stress)
Barbell Curl: EFC: ~0.7 (minimal systemic effect)
These values give context to your training: a workout with two 1.5 rated movements will leave you far more drained than one built around 0.7–0.8-rated isolation lifts — even at the same RPE.
How to Use Fatigability Scores in Training
Now that you understand how to calculate a fatiguability score, the next question is: How do you actually use it? Whether you’re a coach designing a mesocycle or an athlete managing your own training, this score can guide recovery, reduce burnout risk, and improve long-term adaptation.
Here are four key ways to apply fatigability scores in real-world programming:
1. Plan Recovery with Intention
High-fatigability exercises (>40 points) come with a greater recovery cost, not just muscular, but systemic and neurological. Space these out across the week, especially if they involve large muscle groups or high RPEs. For example, avoid stacking squats, deadlifts, and HIIT sprints in the same 24-hour window unless you’re deliberately overreaching. This aligns with periodization principles and emerging models like recovery-adaptability programming (Tuchscherer, 2016; NSCA, 2016).
2. Auto-Regulate Volume Based on Readiness
On days when you're feeling under-recovered, swap in lower-fatigability alternatives, rather than skipping or grinding through a tough workout.
Swap barbell back squats (EFC 1.4) for machine hack squats (EFC ~1.0).
Reduce sets, lower RPE, or choose simpler movement patterns.
This strategy mirrors velocity-based training (VBT) models that reduce load or end sets early based on bar speed drop-off, a proxy for neuromuscular fatigue (Pareja-Blanco et al., 2017).
3. Track Fatigue Over Time
Add up your daily fatiguability scores across a week to get a weekly fatigue load. A gradual rise over weeks is expected in well-planned programs, but a sharp spike, especially without increased sleep or food, may signal a looming crash or need for a deload.
| Total Session Fatigue Score | Risk Level |
|---|---|
| Under 200 | Low (baseline) |
| 200–240 | Moderate (sustainable) |
| 240–280 | Elevated (monitor closely) |
| 280+ | High (consider deload) |
| Population | Typical Weekly Fatigue Score | Training Notes |
|---|---|---|
| Beginner | 100–180 | Fast recovery, less volume needed to progress |
| Intermediate | 180–260 | Need to manage fatigue while progressing volume and intensity |
| Advanced | 220–300+ | Higher tolerance, but risk of overreaching increases |
| Competitive Athlete | 300–360+ | Often includes deload periods; recovery strategy essential |
When scores climb for several sessions in a row, or spike without a recovery plan, that’s a flag to reassess training load, sleep, nutrition, or life stress.
4. Watch for High-Fatigue Clusters
If multiple sessions in a row score 40+ on most lifts, it may be time to pull back. Fatigue isn’t inherently bad, it’s how we grow, but it’s only productive if it’s followed by recovery. Use your score data to time deloads, lower-effort days, or technique-focused blocks.
Conclusion: Train Smart, Not Just Hard
As athletes advance, managing fatigue becomes a cornerstone of sustainable progress. It’s not enough to simply train harder, it’s about training smarter, with an eye toward how each session contributes to long-term stress and recovery. Yet, fatigue has often felt too complex to quantify without advanced monitoring tools like force plates, HRV trackers, or blood lactate meters. This post set out to change that by offering a simple, practical model to estimate fatigability using sets, reps, RPE, and exercise type.
With the fatigability framework, you now have a way to measure the recovery cost of your training sessions in advance. This system brings clarity to exercise selection, helps prevent overreaching, and guides when to push versus when to back off. Instead of guessing how hard your workout hit you, you can assign it a score and adjust based on readiness, lifestyle stress, or programming goals. Over time, tracking these scores can help expose patterns in fatigue accumulation before they show up as missed lifts, nagging soreness, or motivation loss.
Whether you’re an athlete programming your own sessions or a coach overseeing dozens of clients, this tool offers a new level of training awareness. Try using it for a week, and observe how fatigue trends across your training week. To make it even easier I included a Fatiguability Score Calculator down below. Use it and and start quantifying what was once invisible. Because real progress isn’t just about pushing harder, it’s about knowing when not to. You can also use this simple formula in a spreadsheet: Sets × (Reps ^ 0.65) × (RPE / 10) × EFC.
References
Enoka RM, Duchateau J. (2016). Translating Fatigue to Human Performance. Med Sci Sports Exerc, 48(11), 2228–2238. https://doi.org/10.1249/MSS.0000000000000929
Taylor JL, Amann M, Duchateau J, Meeusen R, Rice CL. (2016). Neural Contributions to Muscle Fatigue: From the Brain to the Muscle and Back Again. Med Sci Sports Exerc, 48(11), 2294–2306. https://doi.org/10.1249/MSS.0000000000000920
Hargreaves M. (2016). Metabolic Factors in Fatigue. GSSI Sports Science Exchange, 28(142), 1–7.
Tornero-Aguilera JF, et al. (2022). The Psychophysiological Response to Fatigue. Int J Environ Res Public Health, 19(6), 3481. https://doi.org/10.3390/ijerph19063481
Pareja-Blanco F, Rodríguez-Rosell D, Sánchez-Medina L, et al. (2017). Effects of Velocity Loss During Resistance Training on Athletic Performance. J Strength Cond Res, 31(1), 293–306. https://doi.org/10.1519/JSC.0000000000001516
Stronger By Science (Nuckols, G., & Wolf, M.). (2025). Training to failure: Does it actually make a difference? Retrieved from https://www.strongerbyscience.com
Tuchscherer, M. (2016). Reactive Training Systems: Fatigue percents and autoregulation. Retrieved from https://www.reactivetrainingsystems.com
NSCA (Baechle, T. R., & Earle, R. W., eds.) (2016). Essentials of Strength Training and Conditioning (4th ed.). Human Kinetics.
DISCLAIMER
The information provided in this blog is for educational and informational purposes only and is not intended as medical or training advice. The Fatigability Score is an estimation tool based on practical training variables and should not replace individualized coaching, medical assessment, or evidence-based recovery protocols. Always consult with a qualified fitness professional or healthcare provider before making significant changes to your exercise program.
