Swimming glossary: every term in the app, explained

You open your plan and you read: "400m Cr/Dos (Z1), 8×50: 25m grand chien · 25m normal, 6×100m D1'45" (Z3), 200m RAC". Foreign language? That is normal. Swimming has its own vocabulary. This glossary gathers the terms you meet in ForSwim, and explains them clearly.

Strokes and abbreviations

Cr / NL: front crawl / freestyle In ForSwim you will mostly see Cr (front crawl). NL means nage libre, freestyle: technically any stroke, but in practice it is front crawl, the fastest one.

Dos: backstroke Back crawl: on your back, arms alternating. Often used on the send-off, in recovery, or in the swim-down.

Brasse: breaststroke Arms and legs together, face down. Slower, and useful when you are recovering.

4 nages: individual medley Olympic order: butterfly, then backstroke, then breaststroke, then front crawl. You see it mainly in technique and pool sessions, not at the core of open-water or triathlon plans.

Kick / kickboard Kickboard held out in front, legs only. The aim is an ankle whip, and a long body line.

Gear

Pull buoy A figure-8 float between the thighs. The legs float, so you work mainly the arms and the catch.

Fins They speed the kick up and help the glide and the body roll. Often paired with drills.

Paddles Plates on the hands, to force the catch. Used on some sets. Not on rotation work: there, fins only.

Front snorkel A snorkel in front of the face: you swim without turning the head to breathe. Useful when you are starting out, to feel the glide (often with fins).

Kickboard For the kick sets.

One rule: never a pull buoy and fins at the same time. They do not go together.

Intensity zones (Z1 to Z4)

The zones tell you how fast to swim. In ForSwim they are calculated from your T100 (your best time over 100 m front crawl), not from a 400/200 test.

Z1, very easy. Recovery, the opening, the close. You could talk. At beginner level it is often written "easy".

Z2, endurance. A pace you can hold for a long time. The base of training.

Z3, tempo / lower threshold. A sustained effort, still steady. You can hold it for about 20-30 min.

Z4, threshold / quality. A demanding pace, close to what you can hold over about 1500 m. Quality matters more than volume.

A tag like (Z2 @01:45-01:55) (Premium) is the target pace band for 100 m, taken from your T100.

T100 and paces

T100 Your reference time over 100 m front crawl, pushed off in the water. It is the only pace number ForSwim asks for. From it, the app builds Z1-Z4 and the `@mm:ss` bands.

CSS (Critical Swim Speed) The classic idea of a threshold pace (the swimming cousin of a threshold speed in running). You can measure it with a 400 m and a 200 m, both all-out. The app does not ask you for that test. It uses the T100, so the paces stay simple and match your sessions.

How a ForSwim session is built

Every session follows the same coach order:

1. Opening (about Z1) Get in: front crawl and backstroke, sculling, sometimes fins. No sprint.

2. Technique One focus for the day (roll, catch-up, kick, dog paddle, streamline).

3. Main set The physical block (endurance, threshold, speed, open water), depending on the phase of the plan.

4. Close / RAC, swim-down Very easy swimming to finish. RAC means retour au calme: the swim-down. Often backstroke, your choice of stroke, or "as slow as possible".

Repeats "8×100m" means 8 times 100 m.

Sets A group of repeats with the same goal. The rest is longer between sets than between repeats.

Rest

R15" / R30" / R2' Fixed rest: you touch the wall, you wait exactly that long, you leave. At beginner level the app may write "rest 15 s" instead.

D1'45": leave every 1'45" You leave again every 1 min 45 s, on the pace clock. Swim it in 1'30" and you rest 15". Swim it in 1'38" and you rest 7". The faster you go, the more you rest. (Premium: intervals written as `D...`. Free: often `R...`.)

Active recovery You keep swimming easily between the efforts (backstroke, pull buoy) instead of stopping completely.

Drills

Sculling (godilles) Small hand movements, to feel how the water supports you. Often in the opening or at the end. On your front, or on your back.

Streamline (flèche) A push off the wall, then a glide with the arms long and the head between them, before you swim. A feel for the glide, especially when you are starting out.

Long dog paddle (grand chien) A wide pull, with the arms staying under the water. Feel for the catch. The rhythm stays slow.

Short dog paddle (petit chien) The same idea, with a shorter path, closer to the body. Less common than the long dog paddle.

Catch-up (rattrapé) The lead arm waits, in line with the shoulders, until the other arm leaves. It is about timing and length, not about the hands touching.

Roll (roulis) The body rotates, and a shoulder clears the water. Often with fins, and without paddles.

Glide (coulée) The long position after a push-off or a turn: arms in front, body tight. A few "free" metres if the glide is clean.

Sighting In open water and in triathlon: a short lift of the head to aim at a buoy or a landmark, without breaking the whole stroke.

Negative split The second half is faster than the first. You are controlling the pace.

DPS, distance per stroke Make each arm stroke cover more water: length and efficiency, rather than spinning the arms.

Words you see on a typical session

"all-out" (à bloc): maximal effort

"comfortable" / "easy" (à l'aise / facile): you are not forcing it

"build" (progressif): you speed up along the length, or through the set

"steady" (régulier): the same time on every repeat

"loose" / "relaxed" (souple / relâché): very easy, active recovery

"all-out from the 3rd" (à fond de la 3e): maximal effort on the 3rd repeat, often inside a block of 3

"ankle whip" (fouet des chevilles): a loose kick that starts at the hip, not at the knee

"high elbow" (coude haut): the elbow stays above the hand during the pull

"shoulder rotation" (rotation des épaules): the body turns with each arm (the roll)

"tight torpedo" (torpille gainée): long and aligned, abs on, hips not dropping