Hypertrophy Training Glossary: Key Terms and Definitions

Introduction

If you’ve ever tried to learn about the science of building muscle (hypertrophy), you probably noticed something quickly: the terminology can get confusing.

Hypertrophy research uses a mix of exercise science terms, strength training jargon, and workout programming language. Not all of it is explained clearly on blogs, social media posts, or YouTube videos.

In many cases, even here on the Burn the Fat Inner Circle, my articles don’t pause to define every term – it’s assumed you know the lingo. But if you’re a beginner, you might not.

That’s why I created this glossary.

This is a complete A–Z reference of the most important terms in evidence-based resistance training programming for hypertrophy.

This resource is designed to help you understand the concepts that matter most for building muscle, without burying you in physiology, anatomy, or academic terminology that doesn’t show up in real-world training conversations.

What this glossary includes:

This glossary defines terms related to:

The core training variables that drive hypertrophy (volume, intensity, frequency, rest intervals)
Major mechanisms of muscle growth (mechanical tension, metabolic stress, muscle damage)
Practical programming terminology (periodization, progressive overload, mesocycles)
Essential intensity techniques (drop sets, rest-pause, supersets)
Effort measurement tools (RIR, RPE, proximity to failure)
Modern hypertrophy concepts discussed in research circles.

These are the terms lifters see every day in training plans, articles, podcasts, and scientific papers, and the terms that help provide clarity when you’re analying, choosing, or designing a training plan.

What this glossary does not include:

To keep this resource focused, clear, and beginner-friendly, I intentionally left out:

Nutrition terminology (that will be a separate glossary)
Anatomy (muscle groups, origins/insertions)
Physiology not directly tied to training variables (hormones, metabolic pathways)
Body fat testing methods (Dual-energy-x-ray absorpitometry, bio-electric impedance analysis, air displacement plethysmography)
Supplement terminology

Those topics belong in separate glossaries. Also, I will create nutrition and fat loss terminology glossaries later. This page is dedicated strictly to hypertrophy training, not nutrition or general fitness science.

The terms in this glossary were chosen based on their importance in hypertrophy research and resistance training theory, their usefulness in practical programming, how frequently lifters encouter them online and how often they appear in my own writing and teaching

To avoid redundancy and keep the page easy to navigate, some entries are consolidated under broader terms.

For example, failure subtypes (technical, muscular, absolute) are grouped under Failure, training to, and periodization subtypes (macrocycle, mesocycle, microcycle) are grouped under Periodization.

These “see” references help you find what you need without clutter.

How to use this glossary

The glossary is organized alphabetically so you can easily skim or skip to the word you are looking for.

Each definition is short, simple, and written in plain terms. When a full article on that topic exists on the Inner Circle site, I’ve added a link so you can dig deeper.

If you’re new to training, this glossary will give you the vocabulary to understand programs and make smarter decisions in the gym.

If you’re more advanced, this is a quick reference to align your understanding with current scientific terminology.

Either way, this glossary is here to make hypertrophy training easier to understand, and with the extra tips I’ve included, more effective.

GLOSSARY OF HYPERTROPHY TRAINING & PROGRAMMING TERMS

Absolute failure

See failure, training to

Accessory Exercises

Secondary movements used to complement the main lifts. They target smaller muscle groups, address weak points, or add volume without excessive fatigue. Often used after compound lifts. When time-pressed, the main lift is prioritized and the accessories often skipped. Example: Squat is the main lift. Leg extension is the accessory exercise.

AMRAP (As Many Reps As Possible)

A set performed for the maximum number of reps you can complete with good technique. Often refers to maximum reps in a single set, which also implies training to failure. Sometimes used in workouts where there is a time limit. For example, as many push-ups as you can do in five minutes.

Attentional Focus

See mind to muscle connection (Read more about attentional focus)

Blood Flow Restriction (BFR) Training

A novel lifting method where a cuff is placed around the upper arm or leg to partially restrict venous blood flow while still letting arterial blood to enter the muscle. This makes blood pool in the muscle and increases metabolic stress, which allows muscle growth even with very light weights (30% of your max). BFR is especially helpful during rehab, recovery periods, or for people who can’t train heavy but still want a strong hypertrophy effect.

Breakdown Sets

See drop sets

Compound Exercise

A resistance training exercise that works multiple muscle groups and involves movement at more than one joint (e.g., squat, bench, row). In the case of a bench press, you are not just working your chest. Secondary muscles involved include the front deltoids and triceps. Efficient for building strength and overall muscle mass. Also known as multi-joint exercises.

Concentric muscle action

See muscle action

Concurrent Training

Combining resistance training and cardio (endurance) training in the same program. Excessive endurance work can interfere with strength or hypertrophy (“interference effect”), but it’s mostly in the lower body. Moderate amounts of cardio do not interfere with muscle gains. (Read more about concurrent training)

Daily undulating periodization

See periodization

Deloading

A planned reduction in training stress, usually lowering volume, intensity, load, or a combination of more than one of the above. Helps reduce accumulated fatigue, allows you to recover, and restores performance for the next training cycle. (Read more about deloading)

Descending sets

See drop sets

DOMS (Delayed Onset Muscle Soreness)

Muscle soreness that peaks 24–72 hours after training. Related to, but not the same as, muscle damage. Tends to correlate with an effective workout, but not necessarily a reliable predictor of hypertrophy because it’s possible to get sore and not make any gains. (Read more about DOMS)

Drop Sets

An intensity technique where you reduce the load and continue the set after reaching failure or near-failure. Often repeated multiple times as in a “triple drop.” Increases total reps, total volume, and metabolic stress. Can also be used as a method for time efficiency and progressive overload. (Read more about drop sets)

Eccentric muscle action

The eccentric phase is the lowering portion of a rep, when the muscle lengthens under tension – such as lowering a bench press or descending into a squat. Eccentrics can produce higher force and often create more muscle damage, but slower isn’t always better. A controlled, not exaggerated, eccentric maximizes tension without adding unnecessary fatigue. (Read more about eccentric muscle action)

Eccentric training (“negatives”)

Eccentric training emphasizes the lowering phase of a lift by intentionally increasing the load or slowing the tempo – often called doing “negatives.” This can involve using heavier-than-normal weights with a spotter’s help, slow controlled descents, equipment designed for eccentric overload, or specialized training tactics like 2 up, 1 down. Eccentric-focused methods can increase strength and muscle growth, but they also create more fatigue and muscle damage/soreness, so they should be used selectively.(Read more about eccentric training)

Exercise Order

The sequence you perform exercises in a workout. Standard advice is to do multi-joint lifts first, followed by accessory or isolation work to maximize performance, strength and safety. There are exceptions however, where you might do an isolation exercise first, such as pre-exhaust training which can require lighter weights and be easier on the joints. (Read more about exercise order)

Exercise Selection

Refers to which exercises you choose for a workout. The right choices depend on your goals, experience, available equipment, and individual biomechanics. The exercises you choose have a major impact on which muscles are trained, how much each muscle is challenged (some exercises are more demanding than others), and even which regions of a muscle get the most stimulus. Good exercise selection builds safer, more effective programs, and helps you build strength and muscle proportionately through your whole body.

Failure, Training To

Training to failure means performing a set until you can’t complete another repetition with proper form. Failure isn’t required for hypertrophy, but it can provide additional stimulus when used strategically and when recovery is not compromised. Most lifters benefit from saving failure for the last set of an exercise or using it sparingly, especially on demanding compound lifts. (Read more about failure training)

There are three common types of failure:

Technical Failure: You end the set when form or technique starts to break down, even if you could grind out more reps.

Muscular Failure: You attempt a rep and cannot complete it despite maintaining acceptable technique.

Absolute Failure: You continue until you can’t even complete the easiest part of the rep, often after technique has significantly deteriorated. This type is rarely needed for hypertrophy and adds disproportionate fatigue.

Strategic use of failure can increase effort and stimulate growth, but excessive use reduces performance on later sets and can make recovery harder.

Forced Reps

Forced reps are an intensity technique where a training partner helps you complete additional repetitions after you can no longer lift the weight on your own with good form. The idea is to push past muscular failure and create more fatigue and tension. While popular in traditional bodybuilding gyms, forced reps generate high systemic stress, require careful spotting, and are not mandatory for hypertrophy. When used at all, they should be limited to safe exercises and the final set of a workout. (Read more about forced reps)

Frequency (Training Frequency)

How often you train a muscle each week (it can also describe how many total workouts you do in a week). Most people build muscle and strength well with 3–4 training sessions per week, while more experienced lifters often train 5 days per week. Some advanced bodybuilders train 6 days, but this requires excellent recovery capacity. Even 2 sessions a week can produce measurable gains and easily maintain the muscle you already have.

The ideal frequency depends on your experience, recovery ability, schedule, and total training volume. When matched to your needs, the right frequency can improve performance, recovery, and long-term consistency. (Read more about training frequency)

Full Range of Motion (ROM)

Performing an exercise through the longest safe and controlled movement path your joints allow. Using full ROM generally increases the total distance the muscle works through, which can help recruit more muscle fibers, create more tension, and stimulate greater hypertrophy in many exercises. It can also improve flexibility over time. However, full ROM should always be limited by your individual mobility, comfort, and joint health, not by forcing positions that feel unsafe or unstable. (Read more)

Growth Stimulus Threshold

The minimum level of effort or proximity to failure a set must reach to meaningfully stimulate muscle growth. In practical terms, this usually means getting close enough to failure that the reps become challenging – typically within about 0–3 reps in reserve (RIR).

Sets done too far from failure (for example, stopping with more than 4–5 RIR) generally create too little tension and fatigue in the high-threshold motor units to produce much hypertrophy.

HIT (High Intensity Training)

High-Intensity Training is a style of strength training popularized by Arthur Jones, Mike Mentzer, and later Dorian Yates. It emphasizes very hard effort, often pushing the main working set to true muscular failure, combined with low training volume and relatively infrequent workouts.

The idea is that one all-out, perfectly executed, high-effort set can provide enough stimulus for muscle growth when paired with ample recovery. HIT can be effective for some lifters, but the intensity demands careful form, good judgment, lower volume, and sufficient rest between sessions.

Hypertrophy

Hypertrophy is an increase in muscle size, mainly through the growth of individual muscle fibers. It’s driven by resistance training that provides enough mechanical tension, effort, and total volume to stimulate the muscle to adapt over time. Continued increases in size require progressive overload. Proper recovery and nutrition – especially adequate protein – support this growth process.

Hypertrophy – Mechanisms Of

The main mechanisms proposed to explain muscle hypertrophy are mechanical tension, metabolic stress, and muscle damage. All three can play a role, but research shows that mechanical tension – challenging the muscle through hard, controlled reps close to failure – is the most important. Metabolic stress and muscle damage may contribute, but they are secondary to tension in most practical training programs.

Hypertrophy – Regional

This refers to the idea that different areas within the same muscle (such as the upper vs. lower chest or the long vs. short head of the triceps) can grow differently depending on exercise selection, joint angles, and range of motion. Certain exercises emphasize specific portions of a muscle more than others, making regional development a consideration for balanced physique goals.

Hypertrophy Spectrum (Heavy–Moderate–Light)

The hypertrophy spectrum describes how muscle growth can be achieved using heavy (3–5 reps), moderate (6–12 reps), or light (20+ reps) loads – as long as sets are taken close to failure. This means multiple rep ranges are effective for building muscle, allowing lifters to choose loads that fit their goals, joint health, equipment, and preferences while still stimulating hypertrophy.

Intensity of Effort (RIR, RPE)

Intensity of effort refers to how hard a set feels relative to your true limit. It’s commonly measured using Reps in Reserve (RIR) – how many reps you could have done before reaching failure – or Rate of Perceived Exertion (RPE), a 1–10 scale of difficulty. Managing intensity of effort is essential for hypertrophy, since sets generally need to be taken close enough to failure to provide a strong growth stimulus without creating unnecessary fatigue. (Read more)

Intensity (Load Intensity)

In scientific strength-training terminology, intensity refers to the amount of weight you lift, expressed as a percentage of your one-rep max (1RM). For example, 80% of 1RM is considered a high load, while 40–60% is a light to moderate load. Load intensity influences rep ranges, strength gains, and overall training stress.

Because lifters often use the word “intensity” to describe effort (how hard a set feels), this scientific meaning can be confusing. To avoid mixing the two, many coaches simply say “load” instead of “intensity” when referring to the weight on the bar. Even simpler, just “weight” or “poundage.” (Read more)

Intensity techniques

See drop sets, rest-pause sets, supersets, forced reps

Isolation Exercise

A movement that targets one main muscle group and involves only one primary joint. Examples include biceps curls, triceps pushdowns, lateral raises, and leg extensions. Because isolation lifts place less overall stress on the body, they’re useful for adding extra volume, improving muscle symmetry, or focusing on a specific area without creating much systemic fatigue. They should not replace basic compound movements, they should complement them.

Isometric Training

Isometric training involves contracting a muscle without any movement at the joint – or example, holding a plank, pausing at the bottom of a squat, or performing a static wall sit. Because the muscle works against resistance without changing length, isometrics can build strength at specific joint angles, improve stability and control, and increase time under tension with very little joint stress. They’re useful as accessories in hypertrophy programs or for lifters who need low-impact ways to train around pain or limited mobility.

Junk Volume

Sets that create fatigue without meaningfully stimulating muscle growth. This often happens when sets are performed too far from failure, when the exercise selection doesn’t challenge the target muscle well, or when overall training volume is pushed so high that later sets become low-quality.

Junk volume adds time and stress to a workout without providing a worthwhile return, so managing effort and choosing effective exercises helps ensure each set contributes to hypertrophy instead of simply wearing you out. (Read more)

Load progression

See progressive overload (Read more)

Macrocycle

See periodization

Mechanical Tension

Mechanical tension is the pull or force your muscles feel when they work against resistance. The heavier the weight, the more tension your muscles experience. But you can also create high tension with lighter weights if you take the set close to failure because your muscle fibers still have to work extremely hard to keep moving the weight.

In simple terms, mechanical tension is the feeling of your muscles being “under load,” and it’s the main reason they grow. The goal is to challenge the muscle enough (with either heavy weight or hard effort) that it has to adapt by getting bigger and stronger.

Mesocycle

See periodization

Metabolic Stress

This is the “burning” sensation you feel during tough, higher-rep sets or during techniques like drop sets, supersets, and short rest periods. It comes from the buildup of metabolites (like lactate) as the muscle keeps contracting without full recovery.

This creates a high-fatigue environment inside the muscle that can contribute to hypertrophy, although it’s generally considered less consistent and less influential than mechanical tension. Metabolic stress is a useful secondary stimulus and is often increased through light-to-moderate loads, higher reps, and intensity techniques.

Microcycle

See periodization

Mind to Muscle Connection

The mind to muscle connection refers to directing your attention to the specific muscle you’re trying to train while performing a lift. In scientific terms, this is called attentional focus. Using an internal focus – thinking about squeezing or moving the target muscle – can increase muscle activation in some exercises, especially isolation movements like curls or lateral raises. When training for maximum strength, and external focus may be more helpful. This means focusing on the movement, such as saying “drive the weight up” and on the outcome, such as completing the lift. (Read more)

Minimum Effective Dose (MED)

Minimum effective dose is the smallest amount of training that still produces measurable gains in muscle size or strength over time. In hypertrophy training, this usually refers to the lowest number of hard sets per muscle group per week that still moves you forward.

While some research shows that progress can occur with relatively low volumes, MED for most lifters still means several quality sets taken close enough to failure for each muscle group each week. It’s the lower boundary of productive training – below it, you’re mostly maintaining, not growing.

Maximum Recoverable Volume (MRV)

Maximum recoverable volume is the highest amount of hard training you can do while still recovering well and making progress. When weekly volume climbs past this point, performance usually drops, fatigue accumulates, and results stall or even regress. MRV varies widely between individuals and can change with sleep, stress, nutrition, and training intensity. Staying below your MRV helps you train hard enough to grow without pushing into overreaching or burnout.

Muscle Action (Concentric & Eccentric)

Muscle action refers to the two main phases of a lift: the concentric phase (lifting the weight) and the eccentric phase (lowering it). Both actions contribute to hypertrophy. Eccentrics can produce higher force and often create more muscle damage, which leads some lifters to believe that slow eccentrics automatically build more muscle, but research shows that controlled eccentrics are helpful, not magical. For best results, train both phases: lift with intent, lower with control. Letting the weight drop eliminates tension and reduces the overall growth stimulus. (Read more)

Muscle Damage

Muscle damage refers to the small disruptions in muscle fibers that occur after training, especially when doing new exercises, high volumes, or accentuated eccentric movements. Some soreness can accompany this, but muscle damage itself is not the primary driver of hypertrophy. It’s simply a normal part of the adaptation process. Once the body adapts to a training program, muscle damage decreases – even while muscle growth continues – showing that tension and effort, not damage, are what matter most for hypertrophy.

Muscle Memory

Muscle memory is the phenomenon where regaining lost muscle size and strength happens faster than building it the first time. When you detrained, your muscles shrink, but they keep the added myonuclei from previous training. These myonuclei act like “saved progress,” allowing your muscles to grow back quickly once you start lifting again. Muscle memory is real, measurable, and one of the biggest advantages of having trained consistently in the past.

Muscle Protein Synthesis (MPS)

The process your body uses to build new muscle proteins. Resistance training temporarily increases MPS, and when this repeated rise outweighs muscle protein breakdown over time, muscle growth occurs. Adequate protein intake and recovery help support higher MPS after training.

Muscular failure

See failure training to

Non-interfering supersets

See supersets

Overreaching & Overtraining

Overreaching is a short-term state where training stress temporarily reduces performance, but rebounds with rest and can lead to improved gains – this is called functional overreaching.

Overtraining is a chronic state of under-recovery marked by long-lasting performance decline, fatigue, and stalled progress. True overtraining is rare, while short-term overreaching is fairly common in hard training programs. (Read more)

Periodization

Periodization is a structured approach to organizing training over time by adjusting volume, intensity, and frequency in planned cycles. The goal is to promote steady progress, manage fatigue, and peak performance when needed. Training is typically divided into macrocycles (long-term plans), mesocycles (several weeks of focused training), and microcycles (week-to-week structure). Periodization helps ensure that training stress is challenging but manageable across different phases of a program.

Pre-exhaust (supersets)

Pre-exhaust supersets pair an isolation exercise with a compound lift for the same muscle group (for example, leg extensions before squats). The idea is to fatigue the target muscle first so it becomes the limiting factor in the compound movement.

This can increase time efficiency, increase volume load, and allow a hypertrophic stimulus with less weight on the compound exercise. However, this can compromise weight lifted on the compound movement, limiting strength gains, so this technique is typically used only for hypertrophy goals. (Read more)

Progressive Overload

Progressive overload means gradually increasing the training stress placed on a muscle over time so it continues adapting and growing. Many lifters think overload only means adding more weight, but load is just one method. You can also create overload by adding reps, increasing total weekly volume, improving technique and range of motion, shortening rest periods, or increasing tempo control.

Adding weight (progressive resistance) is one form of overload, but it’s not the only one – any method that raises the challenge by increasing the work done counts. Progressive overload is the foundation of long-term muscle gains. (Read more)

Progression Systems (Single, Double, Triple)

Progression systems are the specific strategies you use to achieve overload over time.

Single progression is the simplest approach – mainly for beginners – where you increase weight whenever you’re ready, even if reps stay the same.

Double progression, the most widely used method, involves building reps within a target range (e.g., 8–12). When you hit the top of the range, you increase the weight and your reps drop back down, then you climb again.

Triple progression expands the concept by progressing three variables – weight, reps, and total volume (sets) – giving another way to apply overload if weight and rep increases have stalled.

All three systems help ensure steady, structured progress in hypertrophy training. (Read more)

Pump

The pump is the temporary swelling and tightness in a muscle you feel during or after training. It’s caused by increased blood flow and the buildup of fluid and metabolites inside the working muscle. A good pump often makes the muscle feel fuller, tighter, and more sensitive to each rep.

The pump is usually achieved through training that creates metabolic stress, such as moderate-to-high rep ranges, shorter rest periods, supersets, drop sets, or isolation exercises.

While a pump is not required for muscle growth, it often signals that you’re targeting the muscle well, using good exercise selection, and working with enough effort to challenge the tissue. Because it reflects metabolic stress, it can correlate with hypertrophy – but it is not the primary driver of it. (Read more)

Proximity to Failure (RIR, RPE)

Proximity to failure describes how close you are to the point where no more reps can be completed with good form. It’s commonly measured with Repetitions in Reserve (RIR) – an estimate of how many reps you have left – or Rate of Perceived Exertion (RPE), a 1–10 scale of effort.

For hypertrophy, training within 1–2 RIR is typically the sweet spot: hard enough to activate the largest, most growth-responsive muscle fibers, but still manageable for recovery. Training to absolute failure isn’t mandatory but using it occasionally – especially on the last set of an exercise – may increase gains and improve your ability to accurately judge how close you really are to failure. (Read more)

Range of Motion (Full, Partial)

Full range of motion (ROM) means moving a joint through its complete safe and controlled arc, typically stretching the muscle at the bottom and contracting it fully at the top. This is the standard recommendation for hypertrophy because full ROM often creates greater tension, improves muscle control, and trains a broader portion of the muscle’s length.

Partial ROM involves limiting part of the movement – usually to emphasize a specific joint angle, maintain constant tension, or handle heavier loads. While full ROM is generally superior for most lifters, partial ROM can still stimulate hypertrophy when applied correctly, especially in advanced programs or when targeting a specific region of a muscle. (Read more)

Relative Intensity

Relative intensity describes how heavy a weight is compared to your maximum strength, usually expressed as a percentage of your 1RM or estimated using RPE. This refers to load, not intensity of effort. For example, lifting 80% of your 1RM is high relative intensity even if you stop several reps short of failure.

Repetition Drop-Off

Rep drop-off is the decrease in reps from one set to the next as fatigue accumulates. Some drop-off is normal in hypertrophy training, especially when using short rest periods, which limit recovery between sets. If rest intervals are too short – or if you’re fatigued or under-recovered – performance can decline more than expected. Managing recovery and rest intervals properly helps keep rep drop-off to a minimum. (Read more)

Rep Progression

See progressive overload

Repetition Tempo

Rep tempo is how quickly you lift and lower a weight (rep speed). A common guideline is about 1–2 seconds to lift (concentric) and 2–3 seconds to lower (eccentric), but tempos can vary depending on the exercise and training goal. Recent research shows that muscle growth is similar across a wide range of rep speeds as long as you maintain control, keep tension on the muscle, and avoid excessive momentum. (Read more)

Reps in Reserve (RIR)

See proximity to failure (Read more)

Rest Intervals (Time Between Sets)

Rest intervals are the amount of time you take between sets before beginning the next one. Longer rests maintain performance and allow you to lift more total weight, while very short rests increase fatigue and can cause reps to drop off from set to set.

For hypertrophy, most lifters grow well using 1–2 minutes of rest. Big compound lifts (squats, presses, rows) often benefit from the longer end of that range to maintain high-quality sets, while smaller isolation lifts can use shorter rests without hurting performance.

For strength, longer rests of 3–5+ minutes are common. This allows near-complete recovery of the nervous system and maximizes force production, which is essential when training with heavy loads or low-rep sets.

For muscular endurance, shorter rests of 30–60 seconds are typically used. This increases metabolic fatigue but reduces force output, which is why it’s not ideal for hypertrophy or strength. (Read more)

Rest-Pause Training

Rest-pause training is an intensity technique where you perform a near-failure set, rest briefly for 10–20 seconds, then continue with one or more mini-sets using the same weight. The short breaks let you recover just enough to squeeze out additional hard reps, creating a large volume of high-intensity effective reps in a short amount of time. It’s commonly used to increase intensity, fatigue, and muscle fiber recruitment without increasing the workout length as much as additional straight sets would. (Read more)

Set Volume

See training volume

Sets (Per Muscle, Per Workout, Per Week)

A set is a group of continuous reps performed without rest. Sets can be counted in several ways:

Per exercise: how many sets you perform of a specific movement (e.g., 3 sets of bench press).

Per workout: the total number of sets you complete in a single session. (e.g. 3 sets of 3 exercises is 9 sets for the workout).

Per week: the total number of sets that target a specific muscle group each week – often the most important measure for hypertrophy (e.g. 6 sets for a muscle per workout twice a week is 16 sets per week).

Most lifters grow well with roughly 10 – 20 hard sets per muscle group per week, depending on experience, recovery, and how close those sets are taken to failure. (Read more)

Single-Joint Exercise

A single-joint exercise is a movement that uses only one primary joint and mainly targets one main muscle group. Examples include biceps curls, triceps kickbacks, lateral raises, leg extensions, leg curls, and calf raises. These exercises are useful for isolating a specific muscle, adding volume with relatively low systemic fatigue, and addressing weak points – often complementing compound lifts, which train multiple muscles and joints at once.

Split Routine

A split routine is a way of organizing your training by dividing workouts according to body parts or movement patterns. Common examples include push/pull/legs, upper/lower, or traditional body-part splits like chest & back / arms & shoulders / legs. Splits help distribute weekly volume across multiple sessions, allowing for more focused work per muscle group and improved recovery between sessions. Body part splits are most popular with bodybuilders. Full body workouts (no split) and upper / lower splits are more popular with recreational lifters. (Read more)

Stimulus-to-Fatigue Ratio (SFR)

A measure of how efficient an exercise is for building muscle. It compares how much growth stimulus a movement provides to how much fatigue it creates. Exercises with a high SFR (like leg presses, machine rows, cable lateral raises) deliver strong tension to the target muscle with relatively little overall fatigue. Exercises with a low SFR (like heavy barbell squats or deadlifts) create a lot of systemic fatigue but don’t produce proportionally more hypertrophy. SFR helps you choose exercises that build muscle effectively without wearing you down.

Supersets (Antagonist, Non-Interfering)

Supersets involve performing two exercises back-to-back with little or no rest between them.

Antagonist supersets pair opposing muscle groups – such as biceps and triceps or chest and back – which often allows one muscle to recover while the other works. This saves time with little or no compromise in muscle and strength gain.

Non-interfering supersets are similar: they combine exercises that don’t affect each other’s performance, such as a lower-body movement with an upper-body movement. Both methods are time efficient and can increase training density without significantly reducing performance in each exercise. (Read more)

Technical failure

See failure training to

Tonnage

See volume load (Read more)

Training Volume

Training volume is the total amount of work performed in a workout or across a week. It can be measured in two main ways:

Volume Load (tonnage): the classic method, calculated as sets × reps × weight. This shows total work done but doesn’t always reflect how much stimulus a muscle receives.

Set Volume (modern standard): the number of hard sets per muscle group per week, which research shows correlates more directly with hypertrophy.

Volume can also be viewed as per session (how many sets you do in one workout) or per week (your total for each muscle group). Most lifters grow well with roughly 10 – 20 hard sets per muscle per week, depending on experience, recovery, and proximity to failure. (Read more)

Training To Failure

See failure training

TUT (Time Under Tension)

Time under tension refers to how long a muscle is working during a set, influenced by rep duration and overall tempo. While increasing TUT can raise metabolic stress, research shows that total tension – the combination of load, effort, and volume – is far more important for hypertrophy than simply making reps slower or extending a set’s duration. In other words, long TUT alone does not build more muscle. TUT can be a useful way to control tempo and improve technique, but meaningful growth still depends on sufficient load, hard sets, and adequate weekly volume. (Read more)

Volume Load

Volume load is the total amount of lifting work performed, calculated as sets × reps × load. It’s one of the most common metrics used in hypertrophy research to quantify training volume and compare different programs or sessions.

When sets are done with sufficient effort (within 1–2 reps in reserve), volume load tends to track well with hypertrophy – higher volume load usually reflects more total tension applied to the muscle. However, volume load can be misleading if effort is too low (if reps are far from failure).

Because of these limitations, many coaches now use set volume (number of hard sets per muscle per week) as a simpler metric for to quantify workload. Still, volume load remains a valuable metric for monitoring workload over time, especially when effort and exercise selection are consistent. (Read more)