Fitness Glossary

Active recovery is low-intensity movement performed on a non-training day or after a hard session, such as easy walking, cycling or mobility work. It is used to maintain blood flow, reduce stiffness and keep clients consistent, not to speed up muscle repair.

The adductors are the group of muscles on the inner thigh that pull the leg towards the midline. They also contribute to hip flexion and extension depending on hip angle, stabilize the pelvis in single-leg stance, and are one of the most commonly strained muscle groups in field sports.

Aerobic capacity is the body's ability to produce energy using oxygen over sustained periods. It is most often quantified as VO2max, but as a training quality it also includes the fraction of that maximum an athlete can hold and how economically they move.

AMRAP means As Many Reps or Rounds As Possible. As a set, it is one set taken to technical failure to test strength or autoregulate load. As a workout, it is a time cap: complete as many rounds of a circuit as you can.

Anaerobic capacity is the total amount of energy the body can produce without oxygen. It determines how much work an athlete can do in efforts lasting roughly 30 seconds to 2 minutes, the range where the effort burns and cannot be sustained.

Autoregulation is adjusting training load, volume or exercise selection based on how a client performs or feels on the day, within rules the coach set in advance. Tools include RPE, RIR, velocity, readiness checks and repetitions-in-reserve caps.

The biceps brachii is the two-headed muscle on the front of the upper arm. It bends the elbow, turns the forearm palm-up, and assists shoulder flexion. Because the long head crosses the shoulder, arm position changes how much the muscle is stretched and how hard it works.

Bioimpedance analysis passes a small electrical current through the body and measures the resistance it meets. Because lean tissue conducts well and fat does not, the device infers total body water, then estimates fat-free mass through an equation. It measures water, not fat.

Block periodization organizes training into consecutive blocks of 2 to 6 weeks, each developing one quality almost exclusively. A typical sequence is accumulation, then transmutation, then realization, so the fitness built early is converted into performance on a target date.

Blood pressure is the force of blood against the artery walls, written as systolic over diastolic in mmHg. Coaches take and record it as a screening measure. Interpreting it, naming hypertension and managing treatment are medical acts, not coaching ones.

BMI, or Body Mass Index, is body weight in kilograms divided by height in metres squared. It is a population screening tool, not a body composition measure: it cannot tell muscle from fat, which is why it misclassifies muscular clients as overweight.

BMR, or Basal Metabolic Rate, is the number of calories the body burns at complete rest to stay alive: breathing, circulation, brain activity and body temperature. It is the largest single component of daily expenditure and the base an estimate of TDEE is built on.

Body composition is the breakdown of body weight into its parts, most simply fat mass and fat-free mass. It explains what scale weight cannot: two clients at the same weight can carry very different amounts of muscle, fat, bone and water.

Body fat percentage is the share of total body weight made up of fat mass. Every field method used by coaches, from skinfolds to bioimpedance, estimates it rather than measures it directly, so it is most useful as a trend and least useful as a single figure.

Body recomposition is losing fat and gaining muscle at the same time, so bodyweight changes little while body composition changes a lot. It happens most readily in beginners, clients returning after a break, and clients carrying higher body fat.

Bulking is a defined phase of eating in a calorie surplus with progressive resistance training to gain muscle. A lean bulk uses a small surplus to limit fat gain; a dirty bulk uses a large one and produces considerably more fat for little extra muscle.

Caffeine is a stimulant that blocks adenosine receptors in the brain, reducing perceived effort and fatigue. Used before training it can support endurance, output and focus. Its main coaching cost is sleep disruption, because it stays active in the body for many hours.

A calorie deficit is eating fewer calories than the body burns, which forces it to draw on stored energy. It is the requirement for fat loss. Coaches create it by lowering intake, raising activity, or both, and size it so the client can actually sustain it.

A calorie surplus is eating more calories than the body burns, giving it extra energy to build tissue. It is the condition that supports maximum muscle gain. Coaches keep it small and paired with progressive resistance training so the weight gained is mostly muscle, not fat.

The calves are the two muscles of the lower leg that point the foot down: gastrocnemius, which crosses the knee and works best with the leg straight, and soleus underneath it, which crosses only the ankle and works with the knee bent. Both feed into the Achilles tendon.

A cancellation policy sets out what happens when a client cancels: the notice required for a session, how a subscription or package ends, what is refunded, and when access stops. Written before it is needed, it prevents most billing disputes.

A check-in is a scheduled, recurring review between a coach and a client that covers the last block of training: what actually got done, what the numbers show, how the client feels, and what changes next. Most coaches run one weekly or every two weeks.

Churn rate is the percentage of clients or recurring revenue you lose over a period. If you start a month with 40 clients and 4 leave, monthly churn is 10%. It is the single number that determines how long clients stay and how hard you have to sell.

Circuit training is a workout format where three or more exercises are performed back to back with little or no rest, followed by a longer rest before the circuit is repeated. It trains muscular endurance and conditioning in a short, time-efficient session.

Client onboarding is everything that happens between a client paying and their first completed workout: collecting health and goal information, setting expectations, getting them set up in your app, and delivering the first program. It is the period that decides whether they stay.

Client retention is the share of clients who stay with a coach over a given period. It is the mirror of churn: if 20 of 100 clients leave in a month, monthly retention is 80%. For a coaching business it drives revenue more than new sales do.

A cluster set breaks one set into small groups of reps separated by short intra-set rests of 10 to 30 seconds. The brief pauses let the lifter keep bar speed and technique high, so more quality reps can be done at a heavy load than in a straight set.

CNS fatigue is a reduction in the nervous system's drive to the muscles, so the same effort produces less force. In gym use the term is applied far more broadly than the evidence supports, and most day-to-day heaviness is peripheral muscle fatigue, poor sleep or life stress.

A coaching niche is the specific type of client a coach chooses to specialize in, defined by who they are and what problem they have, for example desk workers with back pain or runners returning after injury. It narrows the audience so the offer becomes obvious to the right person.

A coaching package is a fixed offer sold as one unit for one price, for example ten sessions, or twelve weeks of online coaching including programming, nutrition and weekly check-ins. It replaces per-session pricing with a defined scope and a defined outcome.

A coaching subscription is an ongoing coaching offer billed automatically at a fixed interval, usually monthly, that continues until the client cancels. It replaces the repeated resell of packages with recurring revenue and an open-ended coaching relationship.

Cold water immersion is submerging the body in cold water, typically around 10 to 15 degrees Celsius for 10 to 15 minutes, after training. It reduces perceived soreness, but done regularly after resistance training it can blunt long-term muscle and strength gains.

A compound exercise is a multi-joint movement that works several muscle groups at once, such as the squat, deadlift, bench press, row and pull-up. Compound exercises allow the heaviest loads, deliver the most training per set, and are usually placed first in a workout.

Concentric is the phase of a rep where the muscle shortens under load, usually the lifting: standing up from a squat, pressing the bar off the chest, curling the dumbbell up. It is the weakest phase of the rep and the one that limits how much weight you can lift.

A cool-down is the low-intensity period at the end of a session, typically five to ten minutes of easy movement and stretching. It brings heart rate down gradually and gives a calm end to training, but it does not prevent DOMS or speed recovery.

The Cooper test measures the greatest distance a person can run in 12 minutes. The result estimates VO2max with the published formula VO2max = (distance in metres - 504.9) / 44.73. It needs only a track, a stopwatch and a maximal effort.

The core is the group of muscles that control the trunk: rectus abdominis, the obliques, transverse abdominis, the spinal erectors, the diaphragm and the pelvic floor. Its main job is resisting unwanted movement of the spine and transferring force between the upper and lower body.

Cortisol is a hormone released by the adrenal glands that mobilises energy, regulates inflammation and follows a daily rhythm peaking shortly after waking. It rises during exercise, which is normal and necessary. It is not the cause of most stalled fat loss.

Creatine is a compound stored mainly in muscle that helps regenerate ATP during short, high-intensity efforts. Taken as a supplement, usually creatine monohydrate at 3 to 5 g a day, it raises muscle creatine stores and supports strength and repeated high-effort work.

CrossFit is a training method built on constantly varied functional movements performed at high intensity, drawing on weightlifting, gymnastics and monostructural conditioning. It is delivered as a daily workout, the WOD, usually in a coached class at an affiliate gym.

Cutting is a defined phase of eating in a calorie deficit to lose body fat while keeping as much muscle as possible. It combines reduced calories, high protein and continued resistance training, and it runs for a set period rather than indefinitely.

A deload is a planned week of reduced training stress, usually lower volume and sometimes lower intensity, that lets accumulated fatigue clear while fitness is retained. It is scheduled every 4 to 8 weeks or triggered by signs of under-recovery, and it is not a week off.

The deltoid is the muscle that caps the shoulder. It has three heads: the anterior head at the front lifts the arm forward, the lateral head at the side lifts it out sideways, and the posterior head at the back pulls it backwards. Together they give the shoulder its width.

A DEXA scan (dual-energy X-ray absorptiometry) passes two X-ray energies through the body to split it into fat mass, lean soft tissue and bone mineral. It gives a regional breakdown limb by limb, and is the most detailed body composition method a client can realistically access.

A diet break is a planned period of one to two weeks at maintenance calories, taken in the middle of a longer fat-loss phase. Unlike a refeed, it lasts weeks rather than days. Coaches use it to relieve diet fatigue and reset before the next deficit block.

DOMS, or delayed onset muscle soreness, is the muscle pain that shows up 12 to 24 hours after unfamiliar or eccentric-heavy training, peaks around 24 to 72 hours, and fades on its own within a few days. Lactic acid is not the cause.

A drop set is a set taken to or near failure, after which the load is immediately reduced by 10 to 30 percent and the set continues without rest, usually for one to three drops. It extends a set beyond the original load's limit.

Dynamic stretching moves a joint actively and repeatedly through its range of motion, such as leg swings or walking lunges, rather than holding an end position. It is the standard choice in a warm-up because it raises temperature and prepares movement without reducing force output.

Eccentric is the phase of a rep where the muscle lengthens under load, usually the lowering: descending in a squat, lowering a bench press, straightening the arm in a curl. Muscles are stronger eccentrically than concentrically, and this phase drives most post-workout soreness.

Electrolytes are minerals that carry an electric charge in body fluid, mainly sodium, potassium, chloride, magnesium and calcium. They regulate fluid balance, nerve signalling and muscle contraction. They are lost in sweat, which is why heavy sweating calls for salt as well as water.

EMOM, or Every Minute On the Minute, is a workout format where a fixed amount of work starts at the top of each minute. Whatever time is left in the minute is rest. Finishing faster earns more rest; slowing down eats into it.

The erector spinae are the columns of muscle running either side of the spine from the pelvis to the skull. They extend the spine, side-bend it, and above all resist flexion: they are what keeps the back from rounding under load in a deadlift, a carry or a bent-over row.

Exercise order is the sequence of movements within a session. Because performance declines as fatigue accumulates, whatever comes first gets the best quality work, so the order should be set by the priority of the block rather than by habit.

Exercise selection is the process of choosing which movements go into a program, based on the goal, the client's anatomy and injury history, the equipment available, and how well the exercise can be progressed and tracked over time.

FFMI, or Fat-Free Mass Index, is fat-free mass in kilograms divided by height in metres squared. It is BMI with the fat removed, which makes it a way of asking whether a client's high body weight is muscle or fat.

Fiber is the part of plant carbohydrate the body cannot digest. It adds bulk without much usable energy, slows digestion, feeds gut bacteria and supports regular bowel function. In coaching it is the macro-adjacent target that most often decides whether a diet feels bearable.

A fitness assessment is the structured set of measurements a coach takes before programming: health screening, body measurements, cardiorespiratory and strength tests, and a movement screen. It establishes a baseline, flags anything needing medical clearance, and gives every future session something to be compared against.

The fitness-fatigue model says every training session produces two effects at once: a long-lasting fitness gain and a larger but faster-decaying fatigue. Observed performance is the sum of the two, which explains why performance often peaks after training load is reduced.

Flexibility is the passive range of motion available at a joint, measured when an external force moves the limb rather than the client's own muscles. It is one component of mobility and is trained mainly through static, dynamic and PNF stretching.

Flexible dieting is an approach where clients hit daily calorie and macronutrient targets from foods of their choosing, rather than following a fixed meal plan. Often called IIFYM, it prioritises adherence and food freedom while keeping the numbers that drive results in place.

The Functional Movement Screen is a standardised set of seven movement tests, each scored 0 to 3 for a total out of 21, plus three pain clearing tests. It is a repeatable movement checklist and asymmetry finder, not an injury risk score or a diagnosis.

Foam rolling is self-myofascial release: applying body weight to a muscle over a foam cylinder or ball. It produces a short-term increase in range of motion and a modest reduction in perceived soreness. It does not break up scar tissue or lengthen fascia.

The forearms are the many muscles between the elbow and the wrist. The flexors on the palm side close the hand and bend the wrist; the extensors on the back side open the hand and straighten the wrist. Together they control grip, which limits many pulling exercises.

Full body training means every session covers the major movement patterns, so each muscle group is trained at every workout. Run two or three times a week, it delivers high frequency with fewer sessions and is the standard structure for beginners and time-limited clients.

Girth measurements are body circumferences taken with a tape measure at standardised sites such as the waist, hips, chest, arms and thighs. They are directly measured rather than estimated, which makes them the most reliable low-cost way to track body shape change.

The glutes are the three muscles of the buttock: gluteus maximus, medius and minimus. Maximus extends the hip and is the body's largest muscle; medius and minimus sit on the side of the pelvis and stop it dropping when you stand on one leg.

The gluteus medius is a fan-shaped muscle on the side of the pelvis that abducts the hip and, more importantly, stops the pelvis dropping when you stand on one leg. It works on every step, and weakness shows up as a hip drop or a knee that caves inward.

The glycemic index (GI) ranks carbohydrate foods from 0 to 100 by how quickly they raise blood glucose compared with pure glucose. High-GI foods raise it fast, low-GI foods more slowly. It applies to single foods eaten alone, which limits how useful it is in a real meal.

The grip strength test measures maximal hand grip force with a dynamometer, in kilograms. It is quick, highly standardized, and widely used as a general marker of overall strength and health status, which makes it one of the most informative readings a coach can take.

The hamstrings are three muscles on the back of the thigh that bend the knee and extend the hip. They run from the sitting bone to below the knee, so they work in every hip hinge, sprint and deadlift, and they brake the leg at the end of each running stride.

Heart rate zones divide the range between rest and maximum heart rate into bands, usually five, each tied to a training effect. Zone 2 builds the aerobic base, zone 4 sits near threshold, zone 5 is maximal work. Coaches use them to prescribe cardio intensity.

HIIT is training that alternates short bouts of near-maximal effort with periods of recovery. The hard intervals typically push heart rate above roughly 85 to 90% of maximum, and the format delivers a large cardiovascular stimulus in much less total time than continuous work.

The hip flexors are the muscles that lift the thigh towards the torso. The main one is iliopsoas, which runs from the lumbar spine and pelvis to the top of the femur; rectus femoris, sartorius and tensor fasciae latae assist. They drive every stride and every knee lift.

HRV, or heart rate variability, is the variation in time between consecutive heartbeats, measured in milliseconds. It reflects autonomic nervous system activity and is used as a rough daily readiness signal. Only a client's own trend is meaningful; comparing HRV between people is not.

Hybrid coaching combines in-person sessions with online programming and remote follow-up. A client might train with the coach once or twice a week and complete the rest of their sessions alone, guided by an app, with check-ins covering the whole week rather than only the supervised part.

Hydration is maintaining the body's fluid balance through what a person drinks and eats against what they lose in sweat, urine and breathing. Even modest dehydration can reduce training performance and concentration, which makes daily fluid intake a basic coaching habit.

Hypertrophy is the increase in muscle size that results from resistance training. It is driven mainly by mechanical tension from hard sets taken close to failure, supported by adequate weekly volume, sufficient protein and recovery. Sets of roughly 6 to 30 reps all produce it.

HYROX is a standardised indoor fitness race: eight 1 km runs alternating with eight functional workout stations, always in the same order. Because the format never changes, results are directly comparable between athletes and between events worldwide.

Ideal body weight is a weight estimated from height and sex using formulas such as Devine, Robinson, Miller or Hamwi. They were built for clinical purposes like drug dosing, not for fitness goals, and they cannot see frame size or muscle mass.

Informed consent is a client's documented agreement to take part in a training program after being told what it involves and what the risks are. It records that the risks were explained and understood, and it is standard practice in fitness before any physical assessment or training begins.

Injury prevention in training means reducing injury risk through load management, strength development and appropriate progression. Managing how quickly training load increases and building strength have the strongest support; stretching and corrective exercise have much weaker evidence.

An intake form is the questionnaire a coach sends before writing a program: health history, injuries, training background, schedule, equipment, nutrition context and goals. It is the difference between a program built for this client and a program built for a general case.

Intermittent fasting is an eating pattern that alternates set periods of eating and not eating, most commonly a daily 8-hour eating window (16:8). It is a way of organising when food is eaten, not a diet in itself; fat loss still depends on the total calories eaten.

An isolation exercise is a single-joint movement that targets one muscle group, such as a biceps curl, leg extension, lateral raise or calf raise. Isolation exercises use lighter loads than compound lifts and are placed later in a workout to add volume to a specific muscle.

Isometric is a muscle contraction where the muscle produces force without changing length, so nothing moves. Planks, wall sits, paused squats and pushing against an immovable bar are all isometric. It builds strength at a specific joint angle and is widely used in tendon rehab.

The lactate threshold is the exercise intensity above which blood lactate starts accumulating faster than the body can clear it. Below it, effort feels sustainable for a long time; above it, fatigue arrives on a clock.

The latissimus dorsi is the large fan-shaped muscle of the back. It runs from the lower spine, pelvis and lower ribs up to the front of the upper arm bone. It pulls the arm down and back, rotates it inward, and gives the back its width.

A lead magnet is something useful a coach gives away in exchange for contact details, usually an email address: a guide, a starter program, a checklist or a short video series. Its job is to turn anonymous attention into a list of people you can contact directly.

Lean body mass is total body weight minus fat mass: muscle, bone, organs, connective tissue and body water. It is the part of a client's weight you are trying to protect during a diet and grow during a training block.

The Leger test, or 20 m shuttle run, is a progressive field test of aerobic fitness. Athletes run between two lines 20 m apart in time with audio beeps that speed up every minute, until they can no longer keep up.

Linear periodization is a training model where volume decreases and intensity increases progressively across a block. A client starts with many reps at moderate load and finishes with few reps at heavy load, moving from general work toward a specific peak.

LISS is low-intensity steady-state cardio: continuous work held at an easy, conversational effort, typically around 60 to 70% of maximum heart rate, for 30 minutes or longer. It builds the aerobic base and costs very little recovery.

LTV, or lifetime value, is the total revenue one client generates across the whole relationship. For a subscription coach the simple version is monthly price divided by monthly churn rate. It tells you what a new client is actually worth and what you can afford to spend to get one.

A macrocycle is the largest planning unit in a training program, typically 3 months to a full year. It contains several mesocycles and is defined by one overarching goal and, when there is one, the date that goal has to be reached.

Macronutrients are the three nutrients the body needs in large amounts and that supply energy: protein, carbohydrate and fat. Protein and carbohydrate provide about 4 calories per gram, fat about 9. Setting them is how a coach turns a calorie target into an actual eating plan.

Maintenance calories are the daily intake at which bodyweight stays stable over time. In practice it equals a client's TDEE. It is the reference point every deficit and surplus is measured from, and the intake a coach returns to between phases.

Maximal Aerobic Speed (MAS) is the slowest running speed at which VO2max is reached, expressed in km/h. It converts a laboratory value into a pace you can write on a programme, so intervals can be prescribed as a percentage of MAS.

Maximal strength is the greatest force a muscle or muscle group can produce in a single voluntary effort, usually expressed as a one-rep max. It is the foundation every other strength quality is built on, including power and strength endurance.

Maximum heart rate (HRmax) is the highest number of beats per minute the heart can reach during all-out exercise. It is the anchor for heart-rate zones. The familiar 220 minus age formula is a population average with wide individual variation.

Maximum recoverable volume is the most training volume a client can do and still recover from before the next session. Past it, performance falls session to session, fatigue accumulates faster than adaptation, and the block has to end.

Meal timing is when a client eats across the day, including meal frequency and nutrition placed around training. Total daily calories and protein matter far more for body composition; timing is a secondary variable that mainly affects training quality, hunger and adherence.

A mesocycle is a training block of roughly 3 to 6 weeks with a single dominant goal, made up of several microcycles and usually ending with a lighter week. It is the level at which a coach decides what quality is being developed right now.

One MET is the energy a person uses sitting quietly at rest, defined as 3.5 ml of oxygen per kilo of bodyweight per minute. An activity at 6 METs costs six times resting energy. METs let you compare any two activities.

Metcon, short for metabolic conditioning, is training designed to improve the body's ability to produce and sustain energy under load. In practice it means high-effort work with short rest, mixing resistance and cardiovascular movements, usually lasting five to twenty minutes.

A microcycle is the smallest structured unit of a training plan, usually one week. It defines which sessions happen, in what order, and how hard each one is, so that the hardest work is placed where the client can actually recover from it.

Mind-muscle connection is the practice of deliberately focusing attention on the target muscle while lifting, feeling it contract and stretch on every rep. This internal focus can increase activation of that muscle in hypertrophy work, while an external focus on the movement or the bar works better for strength and performance.

Minimum effective volume is the smallest amount of training volume that still produces progress for a given muscle or quality. Below it, a client maintains at best; above it, adaptation begins. It is the floor a coach programs from, not a target.

Mobility is the ability to actively move a joint through a range of motion with control. It combines available flexibility with the strength and motor control needed to use that range, which is what separates it from passive flexibility.

MRR, or monthly recurring revenue, is the predictable income a coach receives every month from active subscriptions, normalized to a monthly figure. It excludes one-off sales. It is the number that tells you what you will earn next month before you sell anything.

NEAT, or Non-Exercise Activity Thermogenesis, is the energy burned by everything that is not sleeping, eating or deliberate exercise: walking, standing, fidgeting, housework, commuting. It is the most variable part of daily expenditure between individuals and within the same person over time.

A no-show policy defines what happens when a client does not attend a booked session and does not cancel. Typically the session is charged in full, because the slot could not be reallocated. It is separate from a cancellation policy, which covers sessions cancelled with notice.

The obliques are two layers of abdominal muscle on each side of the trunk. The external obliques run downward and forward, the internal obliques run the opposite way underneath. Together they rotate and side-bend the trunk, and resist rotation, which is what they mostly do in sport.

Online coaching is personal training delivered remotely: the coach writes and updates the program, the client trains alone using an app, and follow-up happens through logged data, check-ins and messaging. There is no supervised session, so the coaching lives in the system around the training.

The overhead squat assessment is a movement screen where a client squats with both arms held overhead while the coach watches from the front and the side. Compensations during the squat show where mobility or control is limited, so you know where to look next.

Overreaching is a short-term accumulation of fatigue that temporarily lowers performance. Functional overreaching resolves within days to about two weeks of reduced load and can rebound above baseline; non-functional overreaching drags on for weeks with no rebound.

Overtraining syndrome is a long-term drop in performance caused by training stress that persistently exceeds recovery, lasting weeks to months and not resolved by a short rest. It is rare in general-population clients and is diagnosed by excluding medical causes.

The PAR-Q, in its current PAR-Q+ form, is a short health screening questionnaire completed before starting physical activity. A yes answer triggers follow-up questions and, where indicated, medical clearance. It is a screening tool that prompts a referral, never a clearance in itself.

Peaking is the final phase of a training plan, in which volume is stripped back and intensity is pushed to near-maximal so a client expresses their best performance on a specific date. It typically lasts one to three weeks and follows a strength or specific preparation block.

The pectorals are the chest muscles. Pectoralis major is the large fan-shaped one running from the collarbone, sternum and ribs to the upper arm; it brings the arm across the body, forward and down. Pectoralis minor sits underneath and tilts the shoulder blade.

The pelvic floor is the sling of muscle that closes the base of the pelvis. It supports the pelvic organs, controls continence, and forms the bottom of the pressurized cylinder that stabilizes the trunk, working with the diaphragm above and the deep abdominals around it.

Periodization is the planned variation of training volume, intensity and exercise selection over time so that adaptation keeps happening and fatigue stays manageable. It splits a season into cycles, each with one clear priority, instead of repeating the same workout indefinitely.

The plank test measures trunk muscular endurance by timing how long a client can hold a front plank on their forearms in a straight line from head to heels. Timing stops when the position breaks, not when the client is uncomfortable.

Plyometrics are exercises that use a rapid stretch of a muscle immediately followed by a shortening - the stretch-shortening cycle - to produce more force than a concentric-only effort. Jumps, bounds, hops and depth jumps are the classic examples.

PNF (proprioceptive neuromuscular facilitation) stretching alternates a stretch with an isometric contraction of the stretched muscle, then relaxation into a deeper position. Contract-relax and hold-relax are the common variants, and PNF typically produces larger acute range gains than static stretching alone.

Positioning is the place a coach occupies in a prospect's mind compared to the alternatives: who they are for, what problem they solve, and why they are the obvious choice for that problem. It is what a prospect can repeat about you after reading one sentence.

The posterior chain is the group of muscles running down the back of the body: calves, hamstrings, glutes, erector spinae and the upper back. They work together to extend the hips and hold the spine, which is what produces force in sprinting, jumping and every hinge.

A posture assessment is a structured static observation of how a client stands, viewed from the front, side and back against a reference line. It is a starting point for exercise selection and a repeatable photo, not a diagnosis and not a prediction of pain.

Power is the rate at which work is done: force multiplied by velocity, measured in watts. In training, it describes how fast an athlete can express strength. Two lifters with the same 1RM can produce very different power outputs.

Price anchoring is the effect of the first price a prospect sees on how they judge every price after it. A coach who shows a premium offer first makes the middle offer feel reasonable; a coach who shows the cheapest first makes everything else feel expensive.

Progress photos are standardised images of a client taken from the same angles under the same conditions at regular intervals. Because they capture shape rather than mass, they show changes the scale misses entirely, and they only work if the conditions are held constant.

Progressive overload is the principle of gradually increasing the demand placed on the body over time so it keeps adapting. In strength training that means more weight, reps, sets, range of motion, control or frequency, tracked from workout to workout.

Protein intake is the daily amount of protein a client eats, usually prescribed in grams per kilogram of bodyweight. For clients training with resistance, a common range in practice is 1.6 to 2.2 g per kg per day, rising to about 2.4 during a calorie deficit.

Push pull legs is a training split that groups exercises by movement pattern: pushing (chest, shoulders, triceps), pulling (back, biceps) and legs. Run over three or six days a week, it trains each pattern once or twice weekly with minimal overlap between sessions.

The push-up test measures upper-body muscular endurance by counting the maximum number of push-ups a client can complete with correct technique. The test ends when form breaks down, not when the client is exhausted, which is what makes the score repeatable.

The quadriceps are the four muscles on the front of the thigh that straighten the knee. Three of them run from the femur to the kneecap; the fourth, rectus femoris, crosses the hip too, so it also lifts the thigh. They drive every squat, lunge, jump and sprint.

Range of motion (ROM) is the distance a joint travels during an exercise, from full extension to full flexion. Full ROM trains the muscle through its entire length; partial ROM deliberately limits the movement, which is useful for overload, injury work or targeting the stretched position.

A refeed day is a planned one- or two-day increase in calories, mostly from carbohydrate, taken during a calorie deficit. It typically brings intake up to around maintenance. Coaches use it to refill glycogen, support training quality and give a diet a psychological break.

A referral program is a structured way of asking existing clients to recommend a coach, usually with a defined reward for the referrer, the new client, or both. It turns recommendations that already happen by accident into a repeatable source of clients.

Relative strength is maximal strength divided by bodyweight, usually expressed as a multiple such as "a 2x bodyweight squat". It is the number that predicts performance in any sport where the athlete has to move their own body.

A rest day is a planned day without structured training, used to let fatigue clear so adaptation from previous sessions can take place. Most general-population clients need at least one or two per week, and rest days can be complete or lightly active.

A rest interval is the time between sets or exercises. It determines how much of the previous set's fatigue carries into the next one, and therefore how much load and how many reps a client can produce. Longer rest favours strength; shorter rest favours density and conditioning.

Rest-pause is a training method where a set is taken to or near failure, followed by a short rest of 10 to 20 seconds, then more reps with the same weight. The cycle repeats 2 to 3 times, packing many high-effort reps into one extended set.

Resting heart rate is the number of times the heart beats per minute at complete rest, ideally measured on waking before getting up. Most healthy adults sit between 60 and 100 bpm, and trained endurance athletes commonly sit between 40 and 60.

Reverse dieting is the gradual increase of calories after a fat-loss phase, usually in small weekly steps, to return to maintenance while limiting fat regain. Coaches use it as a structured exit from a diet rather than an immediate jump back to normal eating.

Rate of force development is how quickly an athlete can build force, measured as the slope of the force-time curve in newtons per second. It matters because most sporting actions allow far less time to produce force than reaching maximum force requires.

The rhomboids are two small muscles under the trapezius that run from the upper spine down and outwards to the inner edge of the shoulder blade. They retract the scapula, pull it slightly upwards, and rotate it downwards, working directly against the muscles that lift the arm overhead.

RIR, or Reps in Reserve, is the number of reps a lifter could have completed with good form when a set ended. 0 RIR is failure, 2 RIR means two reps were left. Coaches prescribe it to control how close to failure each set goes.

The rotator cuff is a group of four muscles, supraspinatus, infraspinatus, teres minor and subscapularis, that run from the shoulder blade to the top of the upper arm bone. They rotate the arm and, more importantly, hold the ball of the shoulder centred in its shallow socket.

RPE, or Rate of Perceived Exertion, is a 1-to-10 scale that rates how hard a set felt. In strength training, RPE 10 means no reps were left, RPE 8 means two reps were left in the tank. Coaches use it to prescribe intensity without a fixed weight.

The Ruffier test is a submaximal cardiac recovery test built on three pulse readings: at rest, immediately after 30 squats in 45 seconds, and one minute later. The three values feed an index that describes how quickly the heart rate returns toward baseline.

A sales funnel is the path a stranger follows to become a paying client, broken into stages: discovering you, showing interest, making contact, deciding, and buying. Mapping it lets a coach see which stage is actually losing people instead of guessing.

The scapula, or shoulder blade, is the triangular bone that sits on the back of the rib cage and carries the shoulder socket. It is held in place by muscle rather than by a tight joint, so it can slide, tilt and rotate, and the arm can only reach overhead if it rotates with it.

Semi-private training is coaching two to six clients in the same session, each following their own individual program. It is not a group class: the clients share the coach and the time slot, but not the workout. It raises revenue per hour without raising the number of hours worked.

The sit-and-reach test measures hamstring and lower-back flexibility. The client sits with legs straight and feet against a box, then reaches forward as far as possible with stacked hands. The distance reached along the box scale is the score.

Skinfold measurement uses calipers to pinch the thickness of skin and the fat underneath at standardised sites. The readings are entered into a regression equation to estimate body fat percentage, or tracked as a raw sum of millimetres, which avoids the equation entirely.

Sleep is the recovery variable with the largest effect on a training client, influencing perceived effort, appetite regulation, mood and injury risk. Most adults need roughly 7 to 9 hours; athletes in heavy training often sit at the top of that range.

The specificity principle states that adaptations are specific to the demands imposed. A client improves most at what they actually practise, in the movement pattern, load range, speed and energy system they train, and much less at everything else.

Static stretching holds a muscle at the end of its range for a sustained period, typically 15 to 60 seconds. It is the most effective method for long-term flexibility gains, and long holds immediately before heavy or explosive work can briefly reduce force output.

Strength standards are reference tables that classify a lift - usually as untrained, novice, intermediate, advanced or elite - based on bodyweight, sex and sometimes age. Coaches use them to give a client context for where their strength sits.

Supercompensation is the classic model in which training causes a temporary drop in performance, recovery returns it to baseline, and a rebound lifts it briefly above the starting point. It explains why the timing of the next session matters.

A superset is two exercises performed back to back with little or no rest between them, followed by a rest before the next pair. Common pairings are agonist-antagonist (chest and back), same-muscle (two chest exercises) and upper-lower. Supersets save time and raise workout density.

Tabata is a high-intensity interval protocol of 8 rounds of 20 seconds all-out work and 10 seconds rest, lasting exactly 4 minutes. The original protocol was performed at maximal effort on a bike; most classes labeled "Tabata" use the timing but not the intensity.

Tapering is a planned reduction in training volume in the days or weeks before a competition or test, while intensity is largely maintained. It clears accumulated fatigue so the fitness built during training can show up as performance on the day.

TDEE, or Total Daily Energy Expenditure, is the total number of calories a person burns in 24 hours. It is the sum of basal metabolic rate, the thermic effect of food, non-exercise activity and training. Coaches use it as the starting point for every calorie target.

Tempo is a four-digit code that sets the speed of each phase of a rep: eccentric (lowering), pause at the bottom, concentric (lifting), pause at the top. A tempo of 3-1-1-0 means three seconds down, one second pause, one second up, no pause.

Tendinopathy is persistent tendon pain and loss of function associated with a change in tendon structure, usually caused by load increasing faster than the tendon adapts. It is a clinical condition: a coach recognises it and refers, never diagnoses or treats.

A testimonial is a client's own account of working with a coach: what their situation was, what changed, and what the coaching was like. It is the main form of proof a coaching business has, because a prospect trusts another client far more than they trust the coach.

The thermic effect of food is the energy the body spends digesting, absorbing and processing what is eaten. It accounts for a modest share of daily expenditure, and protein has the highest thermic cost of the three macronutrients, followed by carbohydrate and then fat.

The thoracic spine is the middle section of the back: twelve vertebrae, each attached to a pair of ribs. It is built for rotation and controlled extension, and when it stiffens, the neck, shoulders and lower back have to move more to compensate.

Time under tension (TUT) is the total time a muscle works during a set, calculated from reps multiplied by the seconds per rep. A set of 10 reps at a 3-0-1-0 tempo produces about 40 seconds of tension. It is an input, not a goal.

Training density is how much work is completed per unit of time, usually expressed as work done divided by session length. Increasing density means doing the same training in less time, or more training in the same time, mainly by manipulating rest.

Training frequency is how often a muscle group, movement pattern or quality is trained in a given period, usually per week. It is distinct from the number of sessions: a client can train four times a week and still hit each muscle only once.

Training intensity has two meanings in strength training: the load relative to a one-rep max (for example 80% of 1RM), and the effort of a set, usually rated with RPE or reps in reserve. A heavy set can be low effort and a light set can be maximal.

A training program is a structured plan of sessions over a defined period, built around a stated goal, with progression written in. It differs from a collection of workouts because each session has a role and the loads or volumes change on purpose over time.

A training split is how a week's training volume is divided between sessions: which muscle groups or movement patterns are trained on which day. Common splits include full body, upper/lower, and push/pull/legs, chosen mainly by how many days the client trains.

Training to failure means continuing a set until no further rep can be completed. Technical failure is the point where form breaks down; absolute failure is when the weight stops moving. It equals RPE 10 or 0 reps in reserve.

Training volume is the total amount of work performed, most usefully counted as hard sets per muscle group per week. It can also be expressed as tonnage (sets x reps x load). Volume is the main lever coaches adjust to drive or manage muscle growth.

The transverse abdominis is the deepest abdominal muscle. Its fibres run horizontally around the waist like a belt, from the spine and pelvis to the front of the abdomen. It does not bend the trunk; it raises intra-abdominal pressure to stiffen the trunk before and during effort.

The trapezius is a large diamond-shaped muscle covering the upper back and neck. It has three functional parts: upper fibres that elevate and upwardly rotate the shoulder blade, middle fibres that retract it, and lower fibres that depress and also upwardly rotate it.

The triceps brachii is the three-headed muscle on the back of the upper arm. All three heads straighten the elbow. The long head also crosses the shoulder, so it is only fully stretched when the arm is overhead, which is why overhead extensions load it differently from pushdowns.

Undulating periodization varies volume and intensity within the week or from session to session rather than across months. A client might train heavy on Monday, moderate on Wednesday and light with high reps on Friday, developing several qualities in parallel.

Unilateral training means working one limb or one side of the body at a time: split squats, single-leg Romanian deadlifts, single-arm rows, single-arm presses. It exposes and reduces left-right strength differences, challenges balance and core stability, and transfers well to running and sport.

An upper lower split divides training into upper body and lower body sessions, usually run four days a week so each half of the body is trained twice. It is the standard four-day structure for intermediates who want frequency without long sessions.

An upsell is offering an existing or buying client something additional or higher-value: a nutrition service alongside training, a higher-touch tier, or a longer commitment. For a coach it is the cheapest revenue available, because the trust and the relationship already exist.

VO2max is the maximum volume of oxygen the body can take in and use per minute during all-out exercise, expressed in millilitres per kilogram of bodyweight per minute (ml/kg/min). It is the single best laboratory marker of aerobic fitness.

Waist circumference is the girth of the abdomen measured with a tape. It is the simplest indicator of abdominal fat, and because abdominal fat is the distribution most linked to metabolic risk, it carries more individual information than BMI while costing nothing.

Waist-to-hip ratio is waist circumference divided by hip circumference. It describes where body fat is stored rather than how much there is, and higher ratios indicate a more abdominal fat distribution, which is the pattern most associated with metabolic risk.

A warm-up is the preparatory phase of a session that raises muscle temperature, takes joints through their range and rehearses the day's movements at progressively increasing load. A typical structure is five to ten minutes of general and specific work, followed by ramp-up sets.

Whey protein is a fast-digesting complete protein derived from milk during cheese-making. It is sold as concentrate, isolate or hydrolysate. It is a convenient way to reach a daily protein target, not a nutritionally superior category of food.

A white label app is a coaching app published under the coach's own brand: their name on the App Store and Google Play, their icon on the client's phone, and no visible trace of the software provider. The technology is licensed; the brand the client sees is the coach's.

The Wilks score is a coefficient that adjusts a powerlifting total for bodyweight so lifters of different sizes can be compared. The total is multiplied by a coefficient derived from a fifth-degree polynomial of bodyweight, with separate coefficients for men and women.

A WOD, or Workout of the Day, is the single prescribed session that every athlete in a gym performs on a given day. It is scored - usually by time, rounds or reps - so results are comparable between athletes and against the same workout later.

A working set is a set performed at the prescribed training load and effort, as opposed to a warm-up set. Working sets are the ones that produce adaptation and the only sets counted toward training volume; warm-ups prepare the client for them.

A one-rep max (1RM) is the heaviest weight a person can lift once with correct form on a given exercise. It can be tested directly or estimated from a multi-rep set, and it is the reference for percentage-based training loads.