S

sand

Loose, granular material that results from the disintegration of rocks and consists of particles smaller than gravel but coarser than silt. Clean, processed sand is used as a medium for swimming pool filters.

sand filter

A large device containing sand (i.e., quartz, silica, or zeolites) through which swimming pool water is passed to remove suspended particles. As water flows from the top of the filter to the bottom, particles of dirt and other solids are trapped by the sand so that cleaner water flows from the base of the filter and back into the swimming pool.

sanitize

To make clean and free from threats to health.

sanitizer

A chemical (e.g., chlorine, bromine, etc.) added to water to break up useless combined chlorine, oxidize organic materials, and kill bacteria and other harmful microorganisms. 

scale

The buildup of calcium carbonate on swimming pool surfaces and plumbing..

scissors kick

A swimming kick used with the sidestroke in which the legs are drawn up toward the body by bending at the hips and knees, separating the legs by extending the top leg forward with foot flexed while bending the bottom leg backwards, and then squeeze legs together in a circular motion until they are extended and together with toes pointed at the end of the kick.

scratch

To drop out of a swimming race for which the swimmer was previously registered.

sculling

A technique for maintaining position in, or moving through, the water by making figure-eight patterns with the hands and arms. The swimmer's body position and the angle of his or her hands while sculling determines the direction the swimmer moves.

scum

A filmy layer of extraneous or impure matter the forms on the surface of the water or clings to the tiles or walls of  a swimming pool.

sediment

Solid material that precipitates out of the water and settles to the bottom of the pool.

sensory functions

The 5 senses of sight, touch, taste, smell, and hearing.

set

A series of swims of a particular distance and interval.

shallow-angle dive

A streamlined headfirst entry into the water at about a 45 degree angle, usually followed by swimming.

shallow-water blackout

Loss of consciousness while underwater swimming in water less than 16 feet deep, often due to hyperventilation and prolonged submersion resulting in cerebral hypoxia.

shocking the water

A phrase referring to breakpoint chlorination (or superchlorination).

skimmer

A device installed in the wall of a swimming pool and connected to the suction line of the pump.The suction pulls in water and any floating debris is trapped in the skimmer basket before the water passes to the pump and  filters.

skimmer basket

A removable strainer within the skimmer that traps large contaminants and debris as water passes through it on the way to the pump and filters.

skimmer gutter

An overflow channel around the perimeter of a swimming pool into which floating debris, oil, and contaminants flow to be separated from pool water before the water is filtered, disinfected, and returned to the pool. Also referred to as the pool gutter.

skimmer net

A mesh net or screen attached to a pole used to remove large floating debris such as leaves, insects, scum, etc. from the surface of the water. The skimmer net is sometimes called a skimmer.

skimmer weir

The small floating door on the side of a skimmer over which water flows to enter the skimmer. The weir prevents debris from floating back into the pool when the pump is turned off.

slurry

Water with a high concentration of suspended solids.

snakebite

An injury caused by the bite of a snake, especially a venomous snake.

soda ash

The commercial name for sodium carbonate. A base used to raise the pH of acidic water.

sodium bicarbonate

A base used to raise the total alkalinity of swimming pool water while having very little effect on the pH. Sodium bicarbonate is known commercially as baking soda.

sodium bisulfate

Also called dry acid. A granular form of acid used to lower the pH or total alkalinity of pool water.

sodium bromide

A salt used to raise bromine levels in a swimming pool (using bromine as a disinfectant) before using bromine tablets.

sodium carbonate

The scientific name for soda ash. A base used to raise the pH of acidic water.

sodium dichlor

A granular, stabilized organic chlorine compound providing 56% to 62% free available chlorine with a pH of 6.9. This compound should be used for regular chlorination only. Superchlorination using sodium dichlor can cause the stabilizer to rise to too high a level, resulting in chlorine lock.

sodium hypochlorite

Liquid chlorine or bleach. Liquid chlorine for swimming pools provide about 12% to 15% free available chlorine with a pH of about 13. Sodium hypochlorite is a cheap form of chlorine, but it is also dangerous to handle and its potency declines rapidly.

sodium sulfite

A chemical that neutralizes chlorine in pool water.

sodium thiosulfate

A chemical that neutralizes chlorine in pool water.

soft water

Water with a low calcium and/or magnesium content. Soft water can result in the etching of swimming pool surfaces. To prevent this, calcium carbonate should be added until the calcium hardness reading is at least 250 ppm.

solar cover

A plastic or vinyl sheet cut into sections that float on the surface of the water (matching the dimensions of the swimming pool) and increase water temperature by absorbing and transferring solar energy. In addition, the pool cover reduces evaporation and pollution from the environment.

solar heating system

A series of panels through which pool water passes to increase its temperature using solar energy.

somersault

A movement on land or in the water in which a person turns forward or backward in a complete revolution bringing feet over head.

specific gravity. 

The ratio of the weight of a liquid or solid to the weight of an equal volume of water. Also, the weight of a gas to the weight of an equal quantity of air.

specificity

A principle of training that the specific benefits of exercise relate to the activity performed.

spinal

Of or relating to the spine.

sphygmomanometer

A medical instrument for measuring blood pressure using an inflatable cuff on the arm that momentarily cuts off blood flow below the cuff. As the air in the cuff is gradually released, the health care professional administering the test listens for the return of the pulse, indicating the patent's systolic (pumping) pressure. As more pressure from the cuff is released, the beating disappears indicating the diastolic (resting) pressure.

spinal canal

The space in the vertebrae and discs of the spinal column through which the spinal cord passes.

spinal column

The skeletal structure of the human backbone, which consists of 29 articulating vertebrae, 9 fused vertebrae, and intervertebral discs situated in the dorsal aspect of the back and which houses and protects the spinal cord.

spinal cord

A long, thin bundle of nervous tissue and support cells that extends from the medulla oblongata of the brain and passes through the spinal column to the rest of the body. The brain and spinal cord make up the central nervous system of the body.

split

A segment or "leg" of a swimming race, usually 1 or 2 lengths of the pool, that is timed separately to evaluate the swimmer's performance during each part. The split is also the time for each segment obtained using a stop watch capable of capturing split times while timing the overall race.

spoon-shaped pool

A swimming pool with a bottom that is rounded upward from the deepest point to all sides.

sprint

A short, fast swim.

stabilized chlorine

The family of organic chlorine compounds that contain a stabilizer (cyanuric acid or iso-cyanuric acid) to protect the chlorine from degradation due to the UV radiation of the sun. The most common types of stabilized chlorine are dichlor and trichlor.

stabilizer

A chemical (typically cyanuric acid) added to swimming pool water to prevent the loss of chlorine due to the effects of UV radiation and heat. Ideally, the stabilizer should be maintained at a level of 40 to 80 ppm.

stain

A discoloration of brown, black, green, or gray on swimming pool surfaces caused by a high concentration of iron, copper, or magnesium in the water.

standard scull

A technique for maintaining position while face up and horizontal using back and forth movements of the hands with palms and fingers flat.

starting block

A raised platform from which a competitive swimmer begins a race. Most starting blocks have handholds for backstroke starts in the water.

sterile

Free from living bacteria and other microorganisms.

sterilize

To apply heat, radiation, or a chemical treatment to make an object free of live bacteria and other microorganisms.

stop watch

A timing device with a start/stop switch for the purpose of accurately clocking the time it takes a swimmer (or a runner) to complete a prescribed distance. In swimming competitions, stop watches and/or other timing devices are used to determine the order of completion.

straight position

A basic diving position in which the body in flight is straight or arched slightly backward with legs together.

streamlined position

The angle of the body and positioning of arms and legs while stroking, kicking, and gliding so that form resistance (i.e., drag caused by the shape of a body moving through the water) is reduced.

stretch cords

Lengths of latex tubing with handles on each end and a nylon loop in the center that can be attached to any stable object so that the ends can be pulled to create resistance and strengthen arms.

stroke frequency

The number of complete arm cycles in a set period.

stroke length

During a swim, the distance traveled during one complete cycle of the arms.

stroke mechanics

The functional details of a swimming stroke (i.e., body position, arm and leg actions, breathing, timing, application of hydrodynamic principles, etc.) used to analyze the stroke and improve performance.

sudden illness

An abrupt change in a person's health characterized by some or all of the following: lightheadedness, weakness, confusion, nausea/vomiting, changes in the level of consciousness, sudden headache or pain in the chest or abdomen, and/or difficulty breathing. Common sudden illnesses are heart attack, stroke, seizure, diabetic emergencies, allergic reactions, and fainting. General care for sudden illness includes monitoring the patient's vital signs and caring for any life-threatening condition, keeping the patient comfortable and reassured, maintaining normal body temperature, administering oxygen if available, and caring for any specific problems that develop (e.g., seizure, vomiting, breathing difficulty, etc.).

superchlorination

The chlorination of a swimming pool in doses that are deliberately selected to produce water free of combined chlorine and organic materials. Superchlorination is also called breakpoint chlorination or shocking the water.

surface dive

A head-first or feet-first submersion from the surface of deep water for the purpose of rescuing a submerged victim, retrieving a submerged object, or swimming underwater. Common surface dives include pike, tuck, quick, and feetfirst.

swim bench

A dry land training system that helps develop muscle memory and overall conditioning. To use a swim bench, the swimmer lies down in prone or supine position and practices strokes while pulling on stretch cords.

swim meet

A competitive event between two or more swim teams that consists of a number of individual swimming races and relays featuring different strokes and distances.

swim team

A group of swimmers who train and compete together.

"swiss cheese" paddles

Hand paddles with holes that reduces the load applied to the shoulder while allowing the swimmer to feel the water as he or she strokes.

synchronized swimming

Rhythmic water activity performed by one or more individuals using sculling and other advanced swimming skills in time with each other and/or the accompanying music.

T

TA

Total alkalinity.

tactile impairment

Partial or total loss of the sense of touch.

takeoff

A leap from the deck, starting block, diving board, or diving platform into the water to initiate a head-first dive or feet-first jump.

taper phase

The final period in a training season, lasting 1 to 3 weeks, in which swimmers reduce workout distance but increase intensity to almost racing speed.

target heart rate range

The range of beats per minute (bpm) of the heart needed to achieve and maintain the ideal intensity for an aerobic workout. This target rate is approximately 60% to 80% of the theoretical maximum heart rate (derived by subtracting the athlete's age from 220).

TDS

Total dissolved solids.

test kit

A manual or electrical device for measuring specific chemical residuals, levels, and/or demands in pool water. Kits usually contain reagents, vials, titrants, and color scales for each test. Common tests include pH, free available chlorine, combined chlorine, total alkalinity, calcium hardness, total dissolved solids, and cyanuric acid.

test strip

A long narrow piece of paper or plastic

tether

A longer stretch cord attached from a swimmer to a stable object at the end of a lane (such as the starting block) to enable the swimmer to swim in place.

top arm

The trailing arm on the sidestroke that rests on the hip during the glide.

top leg

The upper leg on the sidestroke that thrusts forward to complete the kicking motion.

total alkalinity (TA)

The measure of bicarbonate alkalinity in swimming pool water. When TA is between 80 and 120 ppm, this prevents rapid pH changes in the water.

total chlorine

The measure of both free available and combined chlorine in swimming pool water.

total dissolved solids (TDS)

The measure of all dissolved materials in swimming pool water. The maximum acceptable TDS value is 1500 ppm. At values above 1500 ppm, chlorine loses efficiency, pool surfaces begin to be stained, and pool water becomes cloudy.

track start

A competitive start from the starting blocks that looks similar to a runner's start with one foot at the front of the block and the other foot back. To perform this start, the swimmer grabs the block at the ready command and then, uipon hearing the signal to start, pulls on the block to lean forward while pushing off the block with both feet and extending the body forward to enter the water at about a 45 degree angle.

trailing arm

For any stroke with alternating arms, the arm at the side of the body (not extended over the head). In the sidestroke, the trailing arm is the top arm that rests on the hip during the glide phase of the stroke.

training effect

The improvement in functional capacity of body systems (e.g., cardiovascular, respiratory, muscular, etc.) as a result of overloading those systems through exercise.

treading water

A technique for maintaining a vertical position in deep water by sculling with the hands and using a stabilizing kick (e.g., eggbeater kick, whip kick, scissors kick, etc.)

triathlon

A competitive event made up of any three activities but most often the following three in the following order: swimming, biking, and running. Thiathlon distances range from "Sprint" category (0.5-mile swim, 13.5-mile bike race, and 3-mile run) to "Ultra" category (2.4-mile swim, 112-mile bike race, and 26.2-mile run). The most famous Ultra-category triathlon is the Ironman held in Kona, Hawaii. More than 2000 triathlons are held in the United States each year. Of these, 75% are in the International distance category (1.5-kilometer swim, 40-kilometer bike race, and 10-kilometer run).

tuck position

A basic diving position performed by drawing knees to the chest while in upward flight and then straightening and extending the body to enter the water.

tuck surface dive

A headfirst surface dive performed by first bending the legs at the knees and hips, rotating the upper body downward, and then extending the legs upward out of the water to push the body downward.

twist

A rotation along the midline of the body, performed during a diving entry or the front flip turn.