Pilates Glossary: Terms Worth Knowing
The Reformer and Towers at Luma Pilates. Carriage, footbar, shoulder blocks, straps, and Tower frame visible
In a nutshell
A plain-English guide to the terms that come up most in Reformer Pilates classes. Equipment, movement principles, anatomy, and Pilates-specific language. All explained in the way a good instructor would explain them, without unnecessary jargon.
Pilates has its own vocabulary. Most of it is straightforward once someone explains it, but walking into your first class and hearing words like "posterior chain", "neutral spine", or "eccentric loading" without context is unnecessarily confusing.
This glossary covers the terms that come up most at Luma. It is not exhaustive, and it’s not written for specialists. It is written for people who want to understand what their instructor is talking about so they can get more from every class.
In this guide
Equipment
Reformer: The spring-loaded machine at the centre of Reformer Pilates. It consists of a sliding carriage, a footbar, a set of springs, and adjustable straps. The carriage moves along rails in response to your movement, and the springs provide resistance or assistance depending on how they are configured. The same machine works for a complete beginner and an advanced practitioner because every element is adjustable.
Carriage: The sliding platform you lie, sit, kneel, or stand on during a Reformer class. It moves along rails when you push or pull against the footbar or straps. The weight of the carriage and the spring resistance determine how much effort is required to move it.
Footbar: The adjustable bar at one end of the Reformer that your feet push against during footwork and leg press sequences. It can be adjusted to different heights depending on the exercise and the client. A significant amount of the lower body work in a Reformer class is done through the footbar.
Springs: The mechanism that creates resistance on the Reformer. Springs attach the carriage to the frame and can be added or removed to increase or decrease the load. Heavier spring settings create more resistance; lighter settings can provide support and assistance. Your instructor will set the spring configuration for each exercise.
Straps: Loops attached to the top end of the Reformer via a pulley system. They are held in the hands or looped around the feet for arm and leg work. The straps allow the upper and lower body to work through a wide range of movement against the spring resistance.
Box: A padded platform that sits on the carriage and changes the working position for certain exercises. It is used for prone (face-down) work, seated work, and exercises that require the body to be elevated off the carriage surface.
Tower: An attachment to the Reformer that adds a vertical frame with additional spring points above the carriage. Tower classes use this extended range of movement for exercises that cannot be performed on the Reformer alone. At Luma, Tower classes run alongside Reformer classes and use the same machines.
Headrest: The adjustable pad at the top of the carriage that supports the head during lying-down exercises. It can be raised or lowered depending on the exercise and the needs of the individual client.
Shoulder block: Removable padded blocks that sit on the carriage near the headrest end of the Reformer. They provide a surface for the shoulders to press against during footwork and other lying-down exercises, helping to keep the body stable on the carriage as it moves. For certain exercises, your instructor will remove them to create a flatter, unobstructed surface. If you have ever wondered what those pads are for, now you know.
Movement Terms
Footwork: The foundational sequence performed at the start of most Reformer classes. Lying on the carriage with feet on the footbar, clients press and return through a series of foot positions that warm up the lower body, establish spinal alignment, and activate the posterior chain. Footwork looks simple and works hard.
Spinal articulation: The sequential movement of the spine, vertebra by vertebra, rather than as a single unit. Spinal articulation exercises develop mobility through the full length of the spine and are a central part of almost every Reformer class. For people who spend long periods sitting, this work is particularly valuable.
Neutral spine: A spinal position in which the natural curves of the lower back and neck are maintained without exaggeration or flattening. Neutral spine is the starting position for most Reformer exercises and the position the body is working toward in everyday life. Instructors cue neutral spine frequently in the early classes because it is both the foundation of good movement and the position most people have lost through years of poor posture and sedentary habits.
Imprinted spine: An alternative to neutral spine in which the lower back is gently pressed toward the carriage, reducing the lumbar curve. Used in certain exercises where neutral spine is difficult to maintain or where additional core engagement is required. Your instructor will specify when imprinted spine is appropriate.
Eccentric loading: Strengthening a muscle as it lengthens under tension, rather than as it shortens. Most conventional exercise focuses on the concentric phase, the muscle shortening and producing force. The Reformer's spring resistance allows for controlled eccentric loading, which develops strength through the full range of movement and is one of the reasons Pilates produces lasting flexibility gains.
Doming / coning: A visible bulging or ridging along the midline of the abdomen during exercise, caused by intra-abdominal pressure exceeding what the linea alba can currently manage. It is most commonly seen during abdominal loading exercises and is particularly relevant during and after pregnancy, when the linea alba has been stretched and is in the process of regaining its structural integrity. Doming is not something to push through. When an instructor spots it, they will modify the exercise to reduce the load until the tissue is ready for more.
Sagittal plane: The plane of movement that divides the body into left and right halves. Forward and backward movements, such as walking, running, and most gym exercises, occur in the sagittal plane. One of the key advantages of Reformer Pilates is that it trains movement in multiple planes, including the frontal (side to side) and transverse (rotational) planes that sagittal-dominant activities like running leave underdeveloped.
Kinetic chain: The connected sequence of joints, muscles, and connective tissues that work together to produce movement. A restriction or weakness anywhere in the chain affects the whole system. Tight hamstrings, for example, are often connected to restricted hip flexors, a stiff thoracic spine, and overactive lower back muscles. Reformer Pilates addresses the body as a connected system rather than training individual muscles in isolation.
Active flexibility: The range of movement you can control and move through under your own muscular power. Distinct from passive flexibility, which is the range achievable when an external force moves your limb. Active flexibility is what translates into better movement in everyday life and sport. Pilates develops active flexibility through strengthening muscles in lengthened positions, which is more durable and useful than the passive flexibility gained through static stretching alone.
Centring: One of the original Pilates principles. Refers to the initiation of movement from the deep muscles of the trunk, the core stabilisers, rather than from the limbs or the larger superficial muscles. Centring is what makes Pilates movement feel different from other forms of exercise: the effort comes from the inside out, and the peripheral muscles work more efficiently as a result.
Anatomy
Adductors: The group of muscles running along the inner thigh, responsible for drawing the leg toward the midline of the body. They work in close coordination with the glutes and hip flexors to stabilise the pelvis during movement. Weakness or tightness in the adductors is common and often contributes to hip, knee, and lower back pain. Reformer Pilates targets them through both strengthening and lengthening work, particularly in exercises that involve controlled leg movement against spring resistance.
Anterior pelvic tilt: A postural position in which the front of the pelvis drops and the back rises, increasing the curve of the lower back. It is one of the most common postural imbalances seen in people who sit for long periods, driven by tight hip flexors and weak glutes. It contributes to lower back pain, reduced glute activation, and inefficient movement patterns. Pilates addresses it directly through hip flexor lengthening, glute activation, and pelvic alignment work.
Cervical spine: The uppermost section of the spine, comprising seven vertebrae running from the base of the skull to the top of the thoracic spine. It supports the weight of the head and allows the wide range of neck movement. Forward head posture, driven by prolonged screen use and a stiffened thoracic spine, places significant additional load on the cervical spine and the muscles that support it. Reformer Pilates addresses cervical alignment through postural work, thoracic mobility, and deep neck flexor strengthening.
Deep neck flexors: The small muscles running along the front of the cervical spine, responsible for supporting the head in a balanced, neutral position. They are the neck's equivalent of the deep spinal stabilisers in the lower back: close to the bone, essential for postural support, and almost universally underactive in people with chronic neck pain or forward head posture. Pilates engages and strengthens them as part of the broader deep stabiliser work that runs through every class.
Deep spinal stabilisers: The muscles closest to the spine that are responsible for maintaining its position and controlling its movement. The two most important are the multifidus (which runs along either side of the vertebral column and provides segmental stability) and the transverse abdominis (the deepest abdominal muscle, which acts like a corset around the trunk). These muscles are the first to disengage with prolonged sitting and the first target of Reformer Pilates training.
Diastasis recti: A separation of the two sides of the rectus abdominis along the midline, at the linea alba. It occurs to some degree in most pregnancies as the abdomen expands, and varies considerably in severity. Mild diastasis recti is extremely common and resolves naturally for many women with appropriate movement. More significant separation requires specific management: general abdominal loading, particularly exercises that cause doming, should be avoided until the connective tissue has regained sufficient integrity. A women's health physiotherapist can assess the degree of separation and advise on appropriate exercise. Reformer Pilates, when taught by a qualified postnatal instructor, is one of the most appropriate forms of exercise during diastasis recti recovery.
Glutes: The gluteal muscles, comprising the gluteus maximus, medius, and minimus, are the largest muscle group in the body and the primary drivers of hip extension, pelvic stability, and lower limb power. They are chronically underactive in people who sit for long periods, and chronically undertrained in exercise programmes that favour the anterior chain. Reformer Pilates reactivates and strengthens them systematically.
IT band: The iliotibial band, a thick band of connective tissue running along the outside of the thigh from the hip to the knee. It is not a muscle and cannot be stretched in the conventional sense, but tightness and irritation of the IT band is a common source of knee and hip pain, particularly in runners and cyclists. The underlying cause is usually weakness in the glutes and hip abductors. Pilates addresses this through targeted lateral hip strengthening.
Linea alba: The band of connective tissue running vertically down the centre of the abdomen, joining the two sides of the rectus abdominis. It is the structure that separates during diastasis recti. During pregnancy it softens and stretches to accommodate the growing uterus, and after birth it gradually regains its structural integrity. The linea alba responds well to progressive loading but poorly to being overloaded too early. This is why postnatal exercise programming requires care, and why doming during abdominal exercises is a signal to reduce the load rather than continue.
Lumbar spine: The lower section of the spine, comprising five vertebrae between the ribcage and the pelvis. It bears significant load in daily movement and is the most common site of back pain. The lumbar spine is designed to flex and extend but has limited rotation compared to the thoracic spine. It depends heavily on the deep spinal stabilisers, glutes, and hip flexors for support. When these muscles are weak or imbalanced, the lumbar spine compensates, and pain follows.
Patellofemoral joint: The joint between the kneecap (patella) and the thigh bone (femur). It is a common site of pain in runners, cyclists, and people who spend long periods sitting, typically presenting as an ache at the front of the knee. Pain at the patellofemoral joint is usually caused by the kneecap tracking poorly in its groove, which is driven by muscular imbalance: weak glutes and hip abductors allow the femur to rotate inward, pulling the kneecap off its ideal path. Pilates addresses this imbalance directly.
Relaxin: A hormone produced during pregnancy that softens and loosens the ligaments throughout the pelvis and lower back, allowing the pelvis to widen for birth. While this is essential for delivery, it also means the joints of the pelvis and lower back are less stable than usual and more susceptible to strain. Relaxin is one of the reasons why pelvic girdle pain is relatively common during pregnancy, and why loading and impact need to be managed carefully. Its effects can persist for several months after birth, particularly in women who are breastfeeding. This is one of the physiological reasons why returning to high-impact exercise too quickly after birth carries a higher risk of injury than most people realise.
Rotator cuff: A group of four muscles and their tendons that surround the shoulder joint, holding the head of the upper arm bone securely in the shoulder socket. The rotator cuff is responsible for shoulder rotation and contributes to almost every arm movement. It is commonly strained or torn through overuse, impact, or the kind of muscular imbalance that builds up over years of desk work or repetitive upper body training. Reformer strap work supports rotator cuff rehabilitation and strengthening.
Sarcopenia: The gradual, age-related loss of muscle mass and strength that begins in the thirties and accelerates from the fifties onward, particularly in women after menopause as oestrogen levels decline. Sarcopenia is not inevitable, but it does not reverse without resistance training to counteract it. The spring resistance of the Reformer provides the kind of progressive load that stimulates muscle adaptation, making Reformer Pilates one of the most effective and sustainable tools available for managing sarcopenia across the decades.
Pelvic girdle pain: Pain in the joints of the pelvis, most commonly the sacroiliac joints at the back or the pubic symphysis at the front, caused by increased laxity in the ligaments that support them. It is relatively common during pregnancy as relaxin levels rise, and can range from mild discomfort to significant restriction of movement. It sometimes persists after birth. Low-impact, controlled movement such as Reformer Pilates can be appropriate for women with pelvic girdle pain, but the programme needs to be tailored carefully to avoid loading the affected joints asymmetrically. If you have pelvic girdle pain, tell your instructor before class. A women's health physiotherapist should be involved if symptoms are significant.
Parasympathetic nervous system: The branch of the autonomic nervous system responsible for the body's rest, recovery, and restoration. It is the physiological counterpart to the sympathetic nervous system, which drives the stress response. When the parasympathetic nervous system is active, heart rate slows, breathing deepens, digestion resumes, and the body shifts into a state that supports repair and recovery. Yoga practice, particularly breath-focused and restorative styles, is one of the most effective ways to activate the parasympathetic nervous system deliberately. This is why Yoga has a measurable effect on stress levels, sleep quality, and mood, and why it is particularly valuable during periods of sustained physical and psychological demand such as pregnancy and the postnatal period.
Multifidus: A deep muscle running along either side of the spine, attaching to each vertebra. It is the primary stabiliser of the spinal segments and is often underactive in people with lower back pain. Reformer Pilates reactivates and strengthens it systematically over weeks and months of practice.
Transverse abdominis: The deepest of the four abdominal muscles, running horizontally around the trunk like a corset. It is the primary muscle cued when an instructor asks you to draw in or engage your core. Strengthening it is foundational to both spinal stability and pelvic floor function.
Posterior chain: The group of muscles running along the back of the body: the glutes, hamstrings, and spinal erectors. The posterior chain is responsible for hip extension, spinal stability, and the power behind most athletic movement. It is chronically underused in people who sit for long periods, and chronically undertrained in gym programmes that prioritise the anterior (front) chain.
Hip flexors: The muscles connecting the spine and pelvis to the femur (thigh bone) that are responsible for lifting the leg and flexing the hip. They are held in a shortened position during prolonged sitting and become overactive and tight as a result, contributing to anterior pelvic tilt, lower back pain, and reduced glute activation. Reformer Pilates works the hip flexors through their full range rather than simply stretching them, producing more lasting change.
Shoulder girdle: The complex of bones and muscles connecting the arms to the trunk, including the shoulder blades, collarbones, and the muscles that control their position and movement. Poor shoulder girdle function, usually presenting as rounded shoulders and a forward head position, is extremely common in desk workers and people who train with a heavy emphasis on pushing movements. Reformer Pilates targets the specific muscles, the serratus anterior and the lower and middle trapezius, that restore shoulder girdle function.
Serratus anterior: A muscle running along the side of the ribcage that is responsible for holding the shoulder blade flat against the back of the ribcage and allowing the arm to move overhead without impingement. It is commonly weak and underactive, contributing to the "winging" of the shoulder blades that is visible in many people with poor posture. Reformer strap work specifically targets it.
Trapezius: A large muscle covering much of the upper back, divided into upper, middle, and lower portions. The upper trapezius is typically overactive and tight in people who carry tension in the neck and shoulders. The middle and lower trapezius are typically weak and underactive. Reformer Pilates addresses this imbalance directly, which is one reason clients notice reduced neck and shoulder tension relatively quickly.
Thoracic spine: The middle section of the spine, running from the base of the neck to the bottom of the ribcage. It is designed to rotate and extend, but becomes stiff and restricted in people who sit for long periods or train heavily in forward-flexion patterns. Thoracic mobility work is a consistent feature of Reformer classes and one of the areas where clients often notice the most immediate change.
Fascia: The connective tissue that surrounds, connects, and supports muscles and organs throughout the body. Fascial restriction contributes significantly to the feeling of tightness and reduced range of movement that many people experience. It responds well to the slow, sustained, multidirectional movement that Reformer Pilates provides, and less well to static stretching.
Proprioception: Your body's sense of where it is in space and how it is moving. Specialised receptors in the muscles, tendons, and joints feed continuous information to the brain, coordinating movement without conscious thought. Injury, surgery, and prolonged inactivity all disrupt proprioceptive function in the affected area. Rehabilitation therefore involves more than strengthening: the nervous system needs to relearn how to read and respond to movement. The slow, controlled nature of Pilates makes it particularly well suited to this retraining.
Pelvic floor: The group of muscles forming the base of the pelvis, responsible for bladder and bowel control, pelvic organ support, and contributing to deep trunk stability. The pelvic floor works in coordination with the transverse abdominis and the deep spinal stabilisers as part of the core stabilising system. It is oestrogen-dependent and often weakens during perimenopause and menopause. Reformer Pilates engages it as part of every session.
Pilates-specific Terms
BASI: The Body Arts and Science International, one of the most rigorous Pilates teacher training programmes in the world. BASI certification requires comprehensive study of anatomy, movement science, and teaching methodology alongside extensive practical training. Lucia Poulter, Luma's lead instructor, holds Comprehensive BASI certification.
Reformer Fundamentals: The entry-level Reformer class at Luma, designed specifically for people who are new to the machine. It covers how the Reformer works, how to set it up for your body, and the foundational movement principles that underpin every class at every level. It is where all new clients at Luma begin. View the class.
Class levels:Luma's Reformer classes run from Reformer Fundamentals through Reformer Fundamentals Progressing and into Reformer Pilates 1, 2, and 3. The progression is deliberate: each level builds on the previous one, and your instructor will advise when you’re ready to move up. Read our guide on how the Luma class levels work.
Related guides
If any of these terms have led you to a question, these guides go into more detail:
View our class schedule, browse all classes, or get in touch if you have a question that isn’t answered here.
Written by Lucia Poulter
Lucia is lead instructor and co-founder at Luma Pilates, with 26 years of teaching experience and Comprehensive BASI certification. She has spent most of those years translating precise anatomical and movement concepts into language that makes sense to people who are new to the practice. This glossary is that translation in written form.
