🏊Glossary

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15-Metre Rule 15-Metre Rule

The rule requiring a swimmer's head to break the surface by the 15-metre mark after the start and every turn in freestyle, backstroke and butterfly, capping the underwater dolphin-kick phase that would otherwise be faster than surface swimming. It followed David Berkoff swimming most of a backstroke race submerged in 1988. Breaking it is an instant disqualification.

Backstroke Backstroke

The only stroke started in the water, swum face-up with an alternating arm pull while the swimmer must stay on the back except during the turn. Off the start and every wall, up to 15 metres of underwater dolphin kick is allowed before the head must surface, and the finish must be touched while still on the back.

Backstroke Ledge Backstroke Ledge

An adjustable foot wedge fitted to the starting block just below the water's surface, introduced in 2015 to give backstroke swimmers secure footing for the start. Before it, swimmers had to brace bare feet against a slick wall, and the ledge lets them drive back with far more power. It is now standard at major international meets.

Breakout Breakout

The transition from the underwater dolphin-kick phase to the first surface stroke after a start or turn. Surfacing too early wastes the speed of the underwater kick; surfacing too late risks crossing the 15-metre line and disqualification, so elite swimmers drill the timing of the last kick into the first stroke obsessively.

Breaststroke Breaststroke

The slowest and most technical of the four strokes, using a simultaneous, symmetrical frog-kick and arm pull with no alternating or scissor motion allowed. One underwater pull-down with a single downward dolphin kick is permitted after the start and each turn, and every wall touch and finish require both hands arriving together.

Butterfly Butterfly

A stroke with a simultaneous double-arm recovery over the water paired with a dolphin kick, the second-fastest stroke but the most physically punishing. It emerged in the 1930s as a breaststroke variant and became its own Olympic event at the 1956 Melbourne Games. Every turn and finish require a two-hand simultaneous touch.

Catch Catch

The instant an entering hand and forearm anchor the water and begin generating propulsion, the moment that decides stroke quality in every discipline. The modern ideal, the early vertical forearm, bends the elbow high so the forearm and hand form one broad, backward-facing paddle as early as possible in the pull.

Disqualification Disqualification

The nullification of a result for a rules violation, marked DQ on a results sheet. Common causes include a false start, exceeding the 15-metre underwater limit, a one-hand touch in breaststroke or butterfly, an illegal breaststroke kick, a backstroke finish not on the back, and an early relay takeover.

Distance Per Stroke Distance Per Stroke

How far the body travels per arm cycle, often abbreviated DPS and one of the clearest measures of swimming efficiency. Counting strokes over 25 metres reveals it directly, and for a given time, fewer strokes means greater efficiency. DPS is usually the first thing to collapse as fatigue sets in late in a race.

Dolphin Kick Dolphin Kick

A simultaneous, wave-like kick of both legs held together, the base kick of butterfly and the kick used underwater in every stroke. The power comes from undulating the torso and hips rather than the legs alone. Because a streamlined dolphin kick is faster than surface swimming, it is capped by the 15-metre rule.

Drill Drill

A technique exercise that isolates one part of a stroke rather than swimming it in full, such as one-arm freestyle, catch-up drill, or sculling to develop feel for the water. Drills are meant to be swum slowly to groove the movement, not to build speed, and are a staple of every coached lesson.

False Start False Start

Any movement before the starting signal, which has meant instant disqualification with no warning since 1998, replacing an earlier system that forgave a first offence. Relay exchanges are policed on the same principle: an outgoing swimmer's feet must stay on the block until the incoming teammate touches the wall, verified to 0.03 seconds.

Fins Fins

A training aid worn on the feet to boost propulsion, letting a swimmer ride higher in the water to focus on technique while building ankle flexibility and kick strength. Short-bladed training fins are standard for stroke work; the long fins used in snorkelling over-flex the ankle and distort proper kicking form.

Free Swim Free Swim

Open pool time with no instruction, where swimmers train on their own rather than in a lesson, typically organised into lanes by speed with faster swimmers taking the inside lanes. Basic etiquette calls for leaving a gap before following the swimmer ahead and resting tucked in a corner of the wall rather than blocking it.

Freestyle Freestyle

An event that technically allows any stroke, though every swimmer uses the front crawl because it is fastest, so in everyday use "freestyle" and "crawl" mean the same thing. The arms alternate over the water while the legs perform a flutter kick. It is the fastest of the four strokes and closes both the medley and every relay leg.

Freestyle Relay Freestyle Relay

A team event in which four swimmers each cover an equal distance by freestyle, raced over 4x100m and 4x200m. If the incoming swimmer's feet leave the block before the teammate ahead touches the wall, the whole team is disqualified. Exchange timing, verified to 0.03 seconds, is often as decisive as raw speed.

Goggles Goggles

Eyewear that protects the eyes and preserves underwater vision, which spread from the late 1960s and transformed how much swimmers could train. They are effectively mandatory protection against the chlorine in indoor pools. A poor fit leaks regardless of price, so checking the nose-bridge adjustment matters more than the price tag.

Hand Paddle Hand Paddle

A hand-worn training aid that enlarges the pulling surface to sharpen catch feel and build upper-body strength, and doubles as a technique check because a flawed hand path becomes obvious under the extra resistance. Using a paddle too large before the catch is solid raises shoulder load and invites swimmer's shoulder.

High Elbow High Elbow

Holding the elbow above the hand underwater while the forearm stands nearly vertical to anchor the water, formally called the early vertical forearm. It turns the hand and forearm into one broad, backward-facing paddle, maximising propulsion and minimising wasted force, and is one of the most frequently corrected habits in freestyle coaching.

Individual Medley Individual Medley

An event in which one swimmer covers all four strokes in the fixed order butterfly, backstroke, breaststroke, freestyle, contested over 200m and 400m and commonly abbreviated IM. It is considered the truest test of an all-round swimmer; Michael Phelps and Leon Marchand are among its defining champions. Note that the medley relay swaps the stroke order, starting with backstroke instead.

Interval Training Interval Training

Repeating a set distance at a fixed send-off interval, the basic format of masters and post-lesson club training. A set written as "100m x 10 on 2:00" means leaving every two minutes to swim 100 metres and resting whatever time remains, so swimming faster earns more rest.

Kickboard Kickboard

A buoyant board held with both arms to isolate kicking, used by beginners to learn balance and body position and by advanced swimmers for dedicated leg work. Gripping it too hard raises the shoulders and drops the hips, so the arms should stay relaxed and extended.

Lane Rope Lane Rope

A floating rope dividing adjacent lanes that absorbs wake from neighbouring swimmers so it doesn't spread across the pool. The floats are coloured differently in the outer 15 metres and the final 5 metres, marking the underwater limit and the approaching wall. Pulling on it for propulsion is an instant disqualification.

Long Course Long Course

A 50-metre pool, and records set in one. The Olympics and World Championships are both long course, the standard for official world records. Because there are half as many turns as in a 25-metre short-course pool, the same distance produces a slower time.

Masters Swimming Masters Swimming

The internationally used term for adult recreational and competitive swimming, generally open to those 18 or 25 and older depending on the federation. Competitions are split into five-year age brackets so that swimmers of similar age race each other, letting even a late starter compete meaningfully on time.

Medley Relay Medley Relay

A team event in which four swimmers each cover a different stroke in the order backstroke, breaststroke, butterfly, freestyle, standardised at 4x100m and closing the swimming programme at most major meets. Backstroke goes first because it is the only stroke started in the water, the reverse of the individual medley's order, which opens with butterfly. The mixed medley relay, with two men and two women per team, became an Olympic event at Tokyo 2020.

Negative Split Negative Split

A pacing strategy of swimming the second half of a race faster than the first. Going out too hard floods the muscles with lactate and collapses form late in the race, so holding back slightly and closing harder generally produces a better time in events of 200m and longer. The reverse is a positive split, and a race with matching halves is an even split.

Open Water Swimming Open Water Swimming

Distance racing held in the sea, a lake or a river rather than a pool. The Olympic event is the 10km marathon swim, lasting close to two hours with no lanes or walls, decided instead by sighting technique, drafting in a pack, and coping with temperature and current. On-water referees can penalise deliberate obstruction with a yellow flag or a time penalty.

Pace Clock Pace Clock

A large analogue or digital clock on the pool wall with a second hand sweeping a full circle every 60 seconds, used to self-time send-offs and splits. Reading it, starting a set from a fixed number on the clock face and clocking the finish, is one of the first skills required to join club or masters training.

Pull Buoy Pull Buoy

A figure-eight foam float held between the thighs to lift the legs and remove the kick, isolating the arms and upper-body position. It makes technique easier to learn because the body sits higher in the water, but overuse dulls a swimmer's feel for keeping themselves afloat and blunts kick rhythm.

Pullout Pullout

The single underwater pull permitted in breaststroke immediately after the start and each turn, sweeping the hands back to the thighs before stretching them forward again. A 2005 rule change legalised one downward dolphin kick within this sequence, but the head must surface during the first arm stroke and a second dolphin kick disqualifies the swimmer.

Short Course Short Course

A 25-metre pool, and records set in one. Because the doubled number of turns lets swimmers spend more of a race in the fast underwater phase, times are generally quicker than long course, and world records are tracked separately for the two distances. American college swimming uses a third format, 25 yards, not directly comparable to either metric standard.

Split Split

The time recorded for one segment of a longer race, such as each 50-metre interval within a 200m swim, showing how a swimmer distributed effort across the distance. Broadcasts use splits to show the gap to the leader, and in relays, "split" refers to each swimmer's individual leg time.

Starting Block Starting Block

The elevated platform at the pool wall used for a forward dive start in freestyle, breaststroke and butterfly, while backstroke starts in the water from the block's handles. Modern blocks include an angled rear kick plate that adds significant launch power, and a built-in sensor detects the instant the feet leave, used to judge reaction time, false starts and relay exchanges.

Streamline Streamline

A position with the arms extended overhead, hands stacked and biceps squeezing the ears, held off every start and turn to minimise drag. Because water is roughly 800 times denser than air, drag is a swimmer's greatest obstacle, and this position is the single most effective way to reduce it; the fastest moment of any race is the instant right after pushing off the wall in streamline.

Stroke Rate Stroke Rate

The number of arm cycles completed per minute, a measure of a swimmer's tempo. It trades off against distance per stroke: raising the rate adds speed but burns more energy and shortens each pull. Sprinters push it to the limit, while distance swimmers search for the most sustainable balance, often guided by an audible tempo trainer.

Swim Cap Swim Cap

Headwear that keeps loose hair out of pool drains and filtration systems while reducing drag. Mesh caps let water through and are easy to put on; silicone caps cut more drag and keep hair drier but tear more easily on fingernails and are commonly doubled up with a mesh cap underneath for long hair.

Taper Taper

A planned reduction in training volume in the two to three weeks before a target competition, letting the body supercompensate and peak on race day. Too much rest leaves a swimmer flat; too little leaves fatigue in the legs, so getting the dose right is one of a coach's most delicate judgment calls. Shaving body hair to cut drag and sharpen feel for the water often accompanies the taper, together called "shave and taper".

Touchpad Touchpad

An electronic timing panel mounted on the wall of each lane that stops a swimmer's clock the instant it is pressed by hand or body. Introduced from the late 1960s, it eliminated the human judging disputes that once decided close finishes and now times races to the hundredth of a second; if two swimmers register the identical hundredth, the result is declared a dead heat.

Tumble Turn Tumble Turn

A turn in which the swimmer somersaults forward at the wall and pushes off with the feet rather than touching with a hand, also called a flip turn, used in freestyle and backstroke and considerably faster than an open turn. A 1,500m race includes 29 turns, so even a tenth of a second lost at each wall adds up to several seconds by the finish.

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