Equipment and sizing guide

What you need to train jiu-jitsu, how a gi and a rash guard are sized, what to look for in a mat for solo work, and what you do not need.

The short list

For a class you need a gi or a no-gi kit, depending on the class, a mouthguard, and clean feet. For the solo studies in this app you need a padded mat with enough room to lie down and to travel a body length, and nothing else. The model in the studies trains barefoot in a top and shorts because that is the honest minimum, not because it is a recommendation about kit.

Gi sizing

Gi sizes use a letter and a number: A for adult, then a number from 0 to 6 for height and build, with L and H variants for long and heavy frames from some makers. The number is the starting point and the fit is the decision. A jacket should reach the top of the thigh with the sleeves ending at the wrist bone when the arms are held out in front; trousers should reach the ankle bone with the drawstring tied so that the knee patches sit over the knees. Competition rule sets specify sleeve and trouser lengths, so if you plan to compete, measure against the rules of that event rather than against comfort alone.

Cotton gis shrink, usually by a few percent after the first hot washes, and a pearl weave shrinks less than a single weave. Buy for the size after shrinkage if the maker says the gi is unshrunk, and wash cold and hang dry until you know how it behaves. A gi that is too big is a handle for the other person; a gi that is too small restricts the hip movement the studies here are built around.

No-gi kit

A rash guard should be tight enough not to bunch under an arm or a leg and long enough to stay tucked. Grappling shorts have no pockets, no zips and no metal, because those catch fingers and skin; board shorts are a common mistake for that reason. Spats under shorts are optional and are mostly about mat burn and hygiene. Sizing follows normal clothing sizes, but try the movement in the changing room: sit, shrimp and bridge, and see whether anything rides up.

Mats for solo work

The solo studies were written for a mat that is padded enough to bridge and breakfall on and firm enough to post a hand on. Puzzle mats of about 20 to 40 millimetres are the usual home choice; a yoga mat is too thin for the breakfall and the shoulder-stand rock and should not be used for either. You need at least two body lengths in one direction for the hip escape ladder. Clear the area of furniture and edges before you start; the studies say this in their cues because it matters more than any detail of technique.

What you do not need

Gloves, shin guards, headgear and knee pads are not part of ordinary jiu-jitsu training, and this app models none of them. Supplements, straps, wraps and any device that promises to improve flexibility or grip strength are outside what this app can speak to. If you have an injury, a joint that hurts in a particular movement, or a medical condition that a fall or an inversion might affect, the person to ask is a clinician and your coach, not a sizing guide.