Reference
Yoga & Pilates equipment glossary
Thirty terms that appear constantly in equipment listings and rarely get explained. Definitions are written for a practitioner deciding what to buy, not for a materials engineer.
A
- Anti-burst
- A layered construction used in exercise balls so that a puncture releases air slowly over seconds or minutes rather than popping instantly. It does not make a ball puncture-proof; it changes how the ball fails.
- Ascending load curve
- The property of a resistance band whereby tension increases the further it is stretched. It is why a band that feels easy at rest can be difficult at full range, and why most beginners choose a level too heavy.
C
- Closed-cell surface
- A mat surface with sealed cells that do not absorb moisture. Hygienic and easy to clean, but sweat sits on top and reduces grip. Most PVC and NBR foam mats are closed-cell.
- Cross-back strap
- The elastic band running diagonally over the instep on many grip socks. It stops the sock rotating during lateral movement, which is what keeps the tread underneath the foot where it works.
D
- Density
- How much a foam resists compression, independent of how thick it is. Two mats or blocks of identical thickness can behave completely differently under load depending on density.
- Door anchor
- A strap with a stopper that closes into a door frame, giving a resistance band a fixed anchor point at any height. It converts a tube set into a cable-machine substitute for rows, presses, and rotations.
E
- Eccentric phase
- The lowering or returning portion of a repetition, when a muscle lengthens under load. With bands this is the phase most often surrendered by letting the band snap back.
- EVA foam
- Ethylene-vinyl acetate, the closed-cell foam used for most yoga blocks. Available in a wide range of densities — high-density EVA barely compresses under a standing pose, softer EVA is more comfortable under bone.
F
- Fabric loop
- A wide, woven resistance loop with a grippy inner lining, used for lower-body work. It does not roll or pinch on bare skin the way thin latex loops do, at the cost of a shorter usable stretch range.
- Flat band
- A wide, thin, open-ended resistance band — the therapy format. It starts genuinely light, wraps easily around a foot or a hand, and can be cut to length. Also the format most likely to tear suddenly once nicked.
G
- Girth hitch
- The loop-through-itself attachment used to fix a long resistance band to a pull-up bar. Simple and secure, but it should be visually checked before every set on a loaded band.
- Grip sock
- A sock with silicone or rubber tread applied to the sole. Standard in Pilates and barre studios both for hygiene and because studio floors and reformer carriages are deliberately smooth.
L
- Loft
- The thickness of a mat or pad measured at rest. Loft alone does not tell you how much padding you get under a knee — that depends on density as well.
M
- Mini Pilates ball
- A ball of roughly nine inches, deliberately inflated to about three-quarters so it compresses. Used for thigh squeezes, spinal feedback in roll-downs, and small stability challenges. Not a small stability ball.
N
- NBR foam
- Nitrile butadiene rubber foam — the light, cushioned material behind most thick yoga mats. Comfortable and inexpensive; takes a permanent compression set if stored folded.
O
- Open-cell surface
- A mat surface that absorbs moisture, typically natural rubber. Grip improves as the practitioner warms up, at the cost of needing more thorough cleaning and full drying before storage.
- Open-top sock
- A grip sock that leaves the top of the foot exposed, held by a strap. Favoured in corrective settings because an instructor can see foot alignment; offers no warmth.
P
- Proprioception
- The body’s sense of its own position in space, much of it arriving through the soles of the feet. Thinner mats transmit more of it, which is why balance work feels more precise on a thin surface.
- PVC
- Polyvinyl chloride, the traditional sticky-mat material. Denser and more durable than foam with predictable dry grip. Some practitioners avoid it on environmental grounds.
R
- Reformer
- The spring-loaded Pilates apparatus with a moving carriage and a footbar. Its smooth surfaces are the practical reason studios require grip socks with tread extending under the toes.
S
- Sacrum
- The flat, triangular bone at the base of the spine. In supported bridge a block belongs on the sacrum, not in the lumbar curve above it — a distinction that decides whether the pose is restful or uncomfortable.
- Stability ball
- A large inflatable ball, typically 45cm to 85cm, sized to the user’s leg length. Used for core work, mobility, and intermittent seated postural work. Also called a Swiss ball or exercise ball.
- Static load rating
- The manufacturer’s figure for weight resting on an inflated ball. It is a comparative signal of wall thickness and build quality rather than a literal capacity to approach.
- Stir-the-pot
- A stability ball exercise in which the forearms rest on the ball and draw slow circles while the trunk stays rigid. Circle size is the difficulty dial; speed is not part of the exercise.
T
- THERABAND scale
- A clinically standardised mapping of band colour to tension at defined elongation. It is the only cross-brand colour standard, which is why physiotherapy protocols name the brand explicitly.
- TPE
- Thermoplastic elastomer, a mat material sitting between PVC and NBR — lighter than PVC, more resilient than NBR, usually more expensive than either.
- Tread pattern
- The layout of silicone grip on the sole of a sock. What matters is whether it covers the zones your discipline loads — toes for reformer work, ball and heel for mat work — and whether it permits a pivot.
- Tube set
- A resistance band kit of tubular bands with detachable handles, ankle straps, and usually a door anchor. Tubes stack on shared handles for fine resistance control.
- Two-stage inflation
- Inflating a new exercise ball to about 80 percent, waiting 24 to 48 hours for the PVC to stretch, then topping up to full. Skipping it is the usual reason a ball measures under its rated size within a week.
W
- Working length
- The unstretched length of band actually in use between your grip points. Because band resistance depends entirely on stretch percentage, keeping working length consistent is what makes sessions comparable.
Missing a term?
If a phrase in a product listing is not here and it changed your decision, tell us and we will define it. Write to us via the contact page.