In modern society, every subculture has its own terminology and verbiage—the fitness subculture is no different. A few years ago, saying that you were going to “hit the gym” meant you were going to the gym to do a workout. Now the more common phrase is to say that you’re going to HIIT at the gym.

Exercise scientists have a habit of using overly complicated scientific terminology to explain how and why the human body adapts to movement. Gym junkies have developed their own language for describing workouts and the results they can deliver. Both are often describing the same physiological response but in a completely different way.

HIIT, ripped, burned—print and online fitness magazines, blogs and social media personalities often use terms like these to describe the expected outcome of the workouts they are promoting. What do these terms mean? Are these words referring to real outcomes, or are they just buzzwords used to make movement sound harder than it really is? Whether you’re new to the fitness scene or you’ve been working out in health clubs for years, you’ve probably heard certain terms thrown around, maybe you’ve even used a few yourself without really knowing exactly what they mean. In an effort to help you understand what many terms actually mean, here are the explanations of 15 commonly used fitness terms along with a brief, minimally geeky explanation of the science behind the term.


AMRAP is fun way to organize sets of a workout based on a timer, not just counting reps. There are two ways to describe AMRAP: 1) as many repetitions as possible or 2) as many rounds as possible. In the first example, the goal is to perform as many reps of a particular move in a specific amount of time such as 20, 30 or 45 seconds, select a move like body-weight squats, set a countdown timer and do as many as possible before the timer reaches zero. To make the workout really hard, challenge yourself to do more reps with each set. In the second example, the goal is to complete a series of moves as many times as possible. In this example, a workout could feature a circuit of 10 push-ups, five box jumps, pull-ups to fatigue and 20 reverse lunges. Set a timer for 10 minutes and the goal is to complete as many of the complete circuits as possible in the 10 minutes. Either way you choose, an AMRAP should providing a challenging method of working out.


Taken in a literal sense, burning refers to being on fire or possessing an extreme amount of heat. Many consumer-oriented workout programs or club-based group fitness classes promote the fact that they help users work out to the point of “muscle burning.” Does this mean that individuals are expected to work out to the point at which they actually catch on fire? When it comes to movement, burning is often used to refer to the feeling of when muscles experience an accumulation of metabolic waste, creating fatigue. Acidosis is a change in blood acidity, specifically elevated levels of lactic acid and hydrogen ions, often the result of moderate- to high-intensity training. A burning sensation in a muscle is an indication of acidosis and is a sign that it is time for a recovery period to allow the body to remove metabolic waste from the working muscles and replenish the nutrients required to continue performing muscle contractions.


Cardio is short for cardiorespiratory or cardiovascular exercise. It’s used to refer to movement that elevates the heart rate to pump oxygen and nutrient-carrying blood to the working muscles. Most often used for workouts performed on equipment like treadmills, elliptical runners or stationary bikes, it is important to know that ANY movement that elevates the heart rate can provide cardiorespiratory benefits. Circuit training with free weights or performing an AMRAP can be considered cardiorespiratory training.

The perception is that cardio is the best way to burn fat. Fat is converted to muscular energy during lower-intensity training (in fact, you’re in your fat-burning zone while reading this), but it can be a slow process. During higher-intensity training, energy is provided in a shorter period through the glycolytic and phosphagen energy pathways. Rather than using the term “cardio,” it is more appropriate to use the term “energy system training.” Low-intensity training, like walking, draws from the aerobic pathway, moderate- to high-intensity training uses energy primarily from the glycolytic pathway, and extremely high-intensity or maximal-effort training uses the phosphagen pathway.


This is the amount of energy required to raise the temperature by 1 degree centigrade. When you eat, food is digested and stored as glycerols or free fatty acids in adipose tissue or as glycogen muscle cells and the liver. When your body needs energy, it will tap into the most available resource for the immediate need. The human body burns about 5 calories to consume 1 liter of oxygen. During higher-intensity training, using larger muscles in the body consumes more oxygen, resulting in a higher overall caloric burn.

Core Training

This has become one of the most popular and overused fitness terms over the past number of years. It seems as if almost any fitness class, workout program or equipment will provide “core training” benefits. Core is most often used to refer to the muscles that make up the midsection of the body, including the ever-elusive six-pack. However, it is much more effective to think of the body’s core as its center of gravity and not an actual group of muscles. When we look at how the body functions during upright movement patterns such as walking, lifting an object off the ground or moving an object from one place to another, we have to consider the fact that ANY muscle that attaches to the spine, rib cage or pelvis influences movement around the body’s center of gravity.

If we accept the body’s center of gravity as the foundation around which all upright movement is based, then we should consider any move performed from a standing position that affects movement at the spine, rib cage or pelvis as core training. Increase your core strength by pushing your feet into the ground (with your knees slightly bent) as you do movements like barbell rows, overhead presses and one-arm cable presses from a standing position.


Delayed onset muscle soreness—this is the discomfort or soreness you might feel in your muscles the day after a hard or challenging workout. The soreness comes from metabolic byproduct, like lactic acid and hydrogen ions remaining in the muscle tissue after the workout. It also can come from the inflammation that is part of the normal healing process of the muscle repairing itself from the mechanical damage to the individual protein fibers. It seems counterintuitive, but one of the best things you can do when you’re a little sore is to do a low-intensity workout. Elevating your heart rate and boosting your circulation can help speed up the repair process so that you feel better sooner. Follow this link for more information on post-workout recovery strategies.

Every Minute on the Minute (EMOM)

An EMOM is a relatively new way to organize workouts that is based on using a timer. Set a timer for a specific amount of time (for example, 10 minutes), select two to four movements (for example, kettlebell swings and push-ups), start the timer and go! On the even minutes, starting with zero, do 15 push-ups as fast as you can. The remainder of the minute is the rest interval. On the odd minutes, do 20 kettlebell swings, again resting the remainder of the minute once the swings are complete. Following this method, you will do five sets of each movement in 10 minutes. Yes, you will be breathing hard, but it will be worth it!

Fat-Burning Zone

Yes, there is indeed an ideal fat-burning zone. Chances are, you are in it right now. At rest and during low-intensity movement, the body will metabolize fat, specifically glycerols or free fatty acids, into adenosine triphosphate, the chemical that fuels muscle contractions. The downside of using fat for a fuel is that it takes longer to produce energy. As the intensity of the workout increases and your need for energy increases, your muscles will start using carbohydrates stored in the form of glycogen as a source of fuel. Lower-intensity training can use more fat for fuel but may not burn that many calories per minute, while higher-intensity training can burn more total calories but many of them from glycogen, which can leave your body wanting carbohydrates to replace the fuel used during a workout. One important benefit of interval training (see next item) is that your muscles will use glycogen for fuel during the workout. After the workout, your body will use fat for energy to repair the damage done to muscles and replace spent glycogen, which explains EPOC (exercise post-exercise oxygen consumption), the fact that your body can burn calories for a period of time after a really challenging workout.


There has been a mountain of information written about HIIT workouts. No, it’s not a boxing or martial arts class. The acronym stands for high-intensity interval training. This term makes the list because it is often used to refer to movement performed at maximal intensity. However, remember that intensity can be very subjective: What may be low intensity for some may be high intensity for others. Even if you have a history of being sedentary or dealing with chronic medical conditions, then simply walking continuously for a few minutes at a time could be considered “high intensity.” HIIT can be safe and provide many benefits. Don’t let the term scare you away from being physically active.

Metabolic Conditioning

Similar to HIIT, metabolic conditioning is often used to refer to high-intensity training performed to the point of being out of breath or experiencing muscle soreness. Here is why this overused term ought to be retired from our lexicon: Metabolism is the chemical process by which a biological organism produces energy for muscular contraction, meaning that ANY move requiring a muscle contraction (which in itself requires energy) is a form of metabolic conditioning. Standing from your chair after reading this post requires your metabolism to fuel your muscles. If you want to continue using the term, then it would be more appropriate to classify metabolic conditioning as low intensity, moderate intensity, high intensity or maximal intensity to appropriately describe the level of effort required to perform the planned activity.


This term is commonly used to describe a general mode of movement such as yoga or Pilates because they are traditionally performed with body weight (with the exception of Pilates programs involving equipment such as a reformer or barrel) and require concentration to execute challenging movement sequences. Think about a basic machine-based move like a leg extension—doesn’t that require cognitive effort to actively engage and contract the thigh muscles to move the weight? How is that not a mind-body movement? Purposeful movement requires conscious effort. Therefore, almost any physical activity that involves learning and executing movement patterns, no matter how basic, requires cognitive focus and should technically be classified as “mind-body.” Follow this link to learn more about the mind-body connection.

Muscle Confusion

There is a popular consumer-oriented fitness program that claims to be based on the science of muscle confusion. This is simply a marketing term created to describe the physiological effect of periodization, which is a method of organizing workout programs based on alternating periods of intensity. Movement is the process of applying physical stress to the body, but the body actually adapts to the applied stimulus during the post-training recovery period.

The concept of periodization was developed by a Soviet Union sports scientist who recognized that periods of high-intensity training (high stress) should be followed by a period of low-intensity training (low stress) to let the body fully recover from the workouts and allow the time for the physiological adaptations to occur. Two different models of periodization exist: linear, which gradually increases the intensity over a period of time before allowing for active rest or offloading for the body to fully recovery (exercising at 70 percent of max intensity for two weeks followed by two weeks of 80 percent max intensity and two weeks of 90 percent max intensity before taking one week of rest, commonly called “offloading”); and nonlinear, which organizes workouts of varying intensity from one day to the next (high-intensity weightlifting on Monday followed by a low-intensity body-weight workout on Tuesday followed by a moderate-intensity energy system training day on Wednesday). If you want to sound like you know your movement science, then replace muscle confusion with the term periodization. This link can provide more information about how periodization could work for you.


Many programs or fitness classes refer to using plyo, which is short for plyometric. Looking at the etiology of the word, “plyo” (from pleio) is a prefix for “more,” and metric refers to length. Therefore, plyometric means “more length,” which describes the physiological effect of the involved muscles during jump training (the most common application for the lower body) or explosive movements such as medicine-ball throws (often used for upper body-plyometric training).

Plyometric training was developed by a Soviet Union sports scientist who originally referred to it as “shock training” (urdaniye metod in Russian) because of the high forces experienced by the involved tissue. Proper application of plyometric or “shock method” training is performing only a few repetitions at a time in an effort to achieve the highest level of force output possible. Any program requiring participants to perform more than five or six rapid movements (i.e., jumps or explosive lifts) in a row can significantly increase the risk of injury by placing too much force on the involved tissue and is not a true “plyometric” workout.


There are a number of workout programs and classes referencing Tabata, which is an actual person, Izumi Tabata, Ph.D., an exercise scientist from Japan. In 1995, Tabata and colleagues conducted research on ways to improve aerobic capacity using short intervals of extremely high-intensity training. Their research study involved only nine athletes who were challenged to perform two workout protocols at an extremely high intensity. The first protocol involved training at 170 percent of aerobic capacity on cycle ergometers for a work interval of 20 seconds followed by a brief recovery interval of only 10 seconds, repeated to exhaustion. The second protocol was training at 200 percent of aerobic capacity for 30 seconds followed by two minutes of recovery, repeating until exhaustion. Tabata and his colleagues found that the first protocol was extremely effective at boosting aerobic capacity. Since publishing his work in the journal Medicine & Science in Sports & Exercise in 1997, Tabata’s name has been used to refer to a protocol of high-intensity interval training featuring 20-second work intervals followed by 10 seconds of recovery intervals for eight cycles (a total of four minutes).


If you ask most people what their general fitness goals are, you will hear “tone up and get in shape.” We have come to accept the term tone to mean muscular definition or the appearance of a well-defined muscle. The term tone is actually short for tonus, which is the technical term used to describe a state of contraction in a normally functioning muscle. Using a muscle repeatedly during a strength-training workout will leave that muscle in a state of semi-contraction, creating the defined appearance we have come to expect as the result of working out.

Now you know what you’re saying when you use these 15 commonly used fitness terms to describe what you’re feeling during or after a fun, challenging workout.

Photo credit: Meghan Holmes, Unsplash