Swimming And Diving



  • Swimming is the most popular aquatic sports discipline and is an important part of triathlon and water polo.


  • At the international level, aquatic sports disciplines account for the second largest group of athletes at the Olympic Games and are governed by the Fédération Internationale de Natation (FINA).

  • USA Swimming currently has over 400,000 registered athletes and 3100 clubs.

  • US Masters Swimming consists of nearly 60,000 swimmers aged 18 years and older and provides support to more than 1500 clubs and workout groups.

  • USA Artistic Swimming oversees competitive events for artistic (synchronized) swimmers who range in age from 12 to 20+ years.

  • USA Triathlon (USAT) membership has more than tripled in the last 15 years, and there are more than 4300 sanctioned competitions each year.

General Principles


  • Swimming has been a part of the Summer Olympic Games since its inception in 1896.

  • Artistic swimming was first introduced to the Olympics in 1948, but solo and duet competitions did not become official events until 1984. Team artistic swimming was added in 1996.

  • Swimming has been one of the most popular sports in the Paralympic games since their inception in 1960.

  • Open-water swimming became a part of the Summer Olympic Games in 2008.

  • The Ironman Triathlon began in 1978, and the number of participants continues to grow annually.

Types of Sports or Races

  • Freestyle events do not require a particular stroke, but the front crawl is the most popular and commonly referred to as freestyle. Alternating arm strokes and an alternating or “flutter” kick propel the body forward in the prone position.

  • Backstroke events are performed in the supine position with alternating arm strokes and “flutter” kick.

  • Breaststroke events are performed by advancing the arms forward along the midline, then pulling to the sides without leaving the water while executing a “whip” kick by flexing the knees and hips and abducting the legs, and then “whipping” them back together.

  • Butterfly events require the arms to be simultaneously advanced forward above the water and then pulled through underwater, while the legs kick up and down as a single unit similar to a tail in a “dolphin” kick.

  • Relay competitions typically consist of four swimmers. In a medley relay, each swimmer performs one of the four different strokes.

  • Artistic swimming events can consist of solos, duets, teams of 8, and combinations of up to 10 swimmers.

Discussion of Sports-Specific Skills and Other Considerations

  • Successful swimmers are often lean and tall with long limbs, wide shoulders, and large palms with a large muscle mass in the middle and upper body.

  • Elite swimmers tend to be more flexible than their nonelite counterparts.

  • Artistic swimming requires exceptional breath control. Routines typically vary from 2 to 5 minutes in duration with 45%–50% of the time spent underwater.

Biomechanical Principles

  • Achieving balance in the water is the base of swimming.

  • Speed is gained by decreasing drag or resistance while moving through the water.

    • Form drag is body position–dependent water resistance. This type of drag is reduced by using a “streamlined” horizontal position with good body roll and remaining underwater when possible. Optimal hand positioning with slightly spread fingers and change in thumb position during the stroke are also of benefit.

    • Wave drag is caused by turbulence at the water surface. This type of drag is reduced by using deep pools with multiple lane lines, entering the water smoothly, and swimming in the wake of another swimmer (“drafting”).

    • Frictional drag is caused by the contact of the body surface with the water and is reduced by shaving and using specially designed swimwear.

  • Technique and efficiency play a greater role than power in performance.


  • Goggles protect the eyes from chlorine and aid in vision underwater.

  • Caps decrease resistance and keep hair out of the face.

  • Kickboards can be held in the arms while practicing kick techniques.

  • Fins are used to increase kick propulsion in practice.

  • Hand paddles add resistance to the pull during practice.

  • Pull buoys are placed between the legs while practicing pull techniques.

  • Wetsuits can be used for buoyancy and warmth, although studies suggest they do not raise core temperature significantly.

Safety Issues

  • Neck injuries are uncommon, but they can be catastrophic. Preventive measures include a minimum pool depth of 5 feet for dives and flags placed 5 meters from the pool wall to help avoid collisions during backstroke. Backboards should be available and accessible on the pool deck.

  • Sudden death in triathlon is most likely to occur during the swim, at rates more than double that reported in marathons. There is no clear association with skill level or medical problems. No athlete should swim without adequate supervision, which may include motorized and/or nonmotorized craft such as paddleboards or kayaks in larger bodies of water.

  • Artistic swimmers practicing boosts and throws are at increased risk of traumatic injuries, including concussions.

Specific Training and Physiology Issues

  • Although races typically range from 50 to 1500 meters, practices can range from 3000 to over 10,000 meters, which can predispose swimmers to overuse injuries.

  • Several important physiologic changes occur with submersion in water.

    • Gravitational blood pooling in the venous system is decreased, shifting fluids to the central circulation and pulmonary vascular system.

      • Athletes with poor ventricular relaxation or increased pulmonary venous pressure may be at risk of swimming-induced pulmonary edema (SIPE) causing dyspnea and cough productive of pink, frothy, or bloody secretion (reported by 1.4% of triathletes).

      • Overhydration before competition should be avoided. Additional risk factors include older age, female sex, long course events, cold water, hypertension, valvular disease, fish oil supplement consumption, and wetsuit use.

    • The parasympathetic nervous system is activated via the diving reflex.

      • Heart rate is reduced, and vasoconstriction of muscle vasculature preserves blood flow to the brain and heart.

      • These adaptive changes allow for increased time underwater without additional breaths.

    • The sympathetic nervous system may be activated because of the cold shock phenomenon or event-related anxiety.

    • These changes can cause “autonomic conflict” and increase the risk of arrhythmia and sudden death, particularly in athletes with long QT syndrome and/or paroxysmal atrial flutter or fibrillation.

  • Prolonged breath-holding in artistic swimmers can cause hypoxia and is often manifested by dizziness, disorientation, or even syncope.

Unique Environmental and Nutritional Issues

  • Exercise-induced bronchospasm is prevalent in swimmers. Asthmatic children may be drawn to the sport by the warm, humidified air. There is concern exposure to airborne chlorine may lead to airway inflammation and bronchoconstriction in addition to rhinitis, but it is well-tolerated, with no evidence of adverse effects on asthma control in children and adolescents with stable asthma.

  • Swimming with contact lenses has been associated with risk of microbial keratitis. This can be prevented by lens removal, use of goggles, or contact lens disinfection after swimming.

  • Water immersion can expose athletes to a variety of dermatologic issues.

    • Infectious conditions include:

      • Swimmer’s itch (schistosome dermatitis): pruritic, 3- to 5-mm erythematous papules in areas not covered by swimwear: lesions typically resolve spontaneously within 3–7 days

      • Swimming pool granuloma: verrucous nodules or plaques appear over bony prominences 6 weeks after inoculation with atypical mycobacteria; lesions may ulcerate and should be biopsied and treated with warm water soaks and antibiotics.

      • Diving suit dermatitis: diffuse erythematous papules in areas covered by swimsuits caused by Pseudomonas.

      • Seabather’s eruption (sea lice): stinging sensation followed by pruritic vesiculopapular or urticarial rash on areas covered by a swimsuit within 24 hours of saltwater exposure; caused by larvae of thimble jellyfish trapped under swimwear; best treated with cold packs, antihistamines, and topical steroid; can cause febrile reaction.

      • Bikini bottom: firm, deep nodules along the inferior gluteal crease caused by Streptococcus or Staphylococcus aureus resulting from prolonged use of tight-fitting swimwear; best treated with systemic antibiotics and frequent warm soaks.

      • Swimmer’s ear

      • Folliculitis

      • Molluscum contagiosum

    • Athlete’s foot, warts, and pitted keratolysis may also result from skin contact with pool decks.

    • Contact dermatitis can occur from equipment or pool water. More severe forms include aquagenic urticaria, cold urticaria, and contact urticaria related to chlorine exposure.

    • Copper-chelating shampoos and hydrogen peroxide are used to treat the green hair caused by copper ions in pool water.

    • Prolonged water exposure commonly leads to dry, itchy skin, which is treated with application of petrolatum jelly and avoidance of long, hot showers.

    • Open-water swimmers may be at higher risk for skin cancer because of ultraviolet (UV) exposure. Sunscreen is recommended.

  • Open-water swimmers are at increased risk of environmental injuries such as gastrointestinal infection, otitis, sunburn, jellyfish stings, dehydration, hypothermia, and hyperthermia.

    • “After-drop” refers to continued drop in core temperature, which can occur up to 1 hour after cold immersion as cooled peripheral blood returns to the core. Continued exercise, as in triathlon, can also shunt warmed core blood to the periphery.

    • Risk of hyperthermia occurs because of lost ability to regulate body temperature via sweating, radiant heat from the sun, and greater convection and conduction in warmer water. Wetsuits are typically illegal in competition at higher water temperatures to decrease this risk.

  • The necessity for revealing swimwear increases concern about body image and risk of relative energy deficiency, particularly in artistic swimmers.

Common Injuries and Medical Problems

Swimmer’s Shoulder

  • Description: The most common musculoskeletal complaint in competitive swimming; typically results from some combination of intra-articular or subacromial impingement ( Fig. 82.1A ), scapular dyskinesis, overuse, and possible suprascapular nerve entrapment in the setting of joint laxity and rotator cuff muscle imbalance.

    Figure 82.1, Swimmer’s shoulder.

  • History: Pain is typically of gradual onset and often worse during the catch (see Fig. 82.1B ) and early to mid-pull (see Fig. 82.1C ) portions of the stroke. Poor body roll and unilateral breathing increase the propensity for impingement during freestyle.

  • Physical examination: Shoulder and/or core weakness, scapular dyskinesis, poor posture with tight pectoralis musculature, glenohumeral internal rotation deficiency (GIRD), positive impingement testing, dropped elbow during the recovery phase of the stroke, early exit during pull-through, scapular winging, excess body roll.

  • Treatment: Includes avoiding the use of hand paddles, correcting biomechanical deficits.

  • Return to play: Emphasize lower extremity training, avoid strokes that exacerbate pain, and focus on proper technique with good body roll (45 degrees along the long axis); bilateral breathing; and less internal rotation on hand entry for freestyle (fingers first, not thumb).

  • Prevention: Dry land training with stretching and strengthening program for rotator cuff, scapular stabilizers, and core; training distance should be increased by no more than 10% per week.

Breaststroker’s Knee

  • Description: Medial and/or anterior knee pain; the second most common musculoskeletal complaint in competitive swimming

  • History: Results from repetitive valgus loading with breaststroke kick ( Fig. 82.2 ) or the eggbeater kick used in artistic swimming and water polo

    Figure 82.2, Knee pain associated with kick.

  • Physical examination: Medial collateral ligament (MCL) sprain, medial patellar facet tenderness, and/or inflamed medial synovial plica may be noted

  • Diagnostic considerations: More common in older, more competitive swimmers with more years of experience

  • Treatment: Cessation of breaststroke kick; lower extremity and core strengthening

  • Return to play: Gradual reintroduction of breaststroke kick with proper technique—hip abduction between 37 and 42 degrees, with good external rotation and dorsiflexion of the ankles

  • Prevention: Gradual increase in breaststroke distance; stroke diversity and stroke-specific warm-up; maintain quadriceps and hamstring flexibility

Spine Pain

  • Description: Occurs in approximately 20%–25% of swimmers in a single season; facet pain results from lumbar hyperextension required for streamlined position; pain may also result from repetitive flexion of the thoracic spine in butterfly stroke and with diving from the starting block ( Fig. 82.3 ).

    Figure 82.3, Low back pain.

  • History: Pain is often accentuated by the use of the dolphin kick, in addition to fins, kickboards, and pull buoys, and increases with training intensity, duration, and distance. Flexion-based pain and facet joint injury can also result from spine rotation and flexion during flip turns.

  • Physical examination: Pain can be flexion-based or extension-based as detailed earlier

  • Differential: Spondylolysis/spondylolisthesis and discogenic pain

  • Return to play: Gradual reintroduction of butterfly, dolphin kick, and flip turns

  • Prevention: Gradual increases in butterfly and dolphin kick, stroke diversity, core strengthening and stabilization

Swimmer’s Ear

See Chapter 48 : “Maxillofacial Injuries.”

  • Prevention: Dry canals with hair dryer, and maintain acidic environment with ear drops; use molded ear plugs in cold-water swimming.

Thoracic Outlet Syndrome

  • Description: Impingement of the brachial plexus and/or vascular supply to the upper extremity occurring in the interscalene triangle, the costoclavicular space, or the coracopectoral tunnel ( Fig. 82.4 )

    Figure 82.4, Thoracic outlet syndrome anatomy.

  • History: Sensation of aching or coolness radiating down the arm associated with exertion and overhead activities

  • Physical examination: Findings include weakness or fatigue in the involved nerve root distribution, decrease in radial pulse in the affected arm noted while pulling down on the arm and having the patient inhale deeply and turn the head toward the affected side (Adson maneuver), and reproduction of symptoms by placing the arm in hyperabduction and external rotation (Wright test) or by manually compressing the clavicle.

  • Diagnostic considerations: Imaging may include apical lordotic view of the chest to look for a cervical rib, plain films of cervical spine and shoulder, and/or arteriogram. Nerve conduction studies may be useful in brachial plexus involvement. Axillary vein thrombosis should be considered in patients with arm swelling and venous distension.

  • Treatment: Strengthen scapular elevators, stretch cervical girdle, address poor posture, and avoid provocative positions; surgical treatments include rib resection and scalene release.

  • Return to play: Stroke modification to minimize impingement



Diving is an aquatic sport that involves an aerial acrobatic maneuver after jumping or falling from a platform or springboard at measured height into water.


  • Approximately 12,000 athletes register with USA Diving each year.

  • Typical age of Olympic-caliber divers: 12 years to mid-20s

  • Most data on injury come from World Championships or Olympics

    • Injury rate 8.9% (female 5.9%, male 10.4%) with 8.3% in competition and 58.3% in training

    • Clinical incidence of injury in males is 1.94, and in females 2.49

    • Shoulder injuries are the most common injury in males, whereas trunk injuries are more common in females

    • Low back pain is the most commonly reported injury in elite competitive divers (38.4%–49%)

    • Most injuries are overuse injuries (male 24%, female 21.6%). Competitive divers train on average 40 hours per week, with springboard divers averaging 100–150 dives per day and platform divers averaging 100–150 dives per day.

General Principles


  • Save: in order to “save” a dive (avoid a nonvertical entry) a diver hyperflexes the shoulders and hyperextends the spine

  • Swimout: occurs during entry into the water, where arms are forcibly pulled forward to the side in an attempt pull in the rest of the body with minimal splash

  • Dive groups (designated by numbers 1–6) and dive body positions (designated by letters A–D) make up a dive (see Tables 82.1 and 82.2 and Box 82.1 for dive descriptions and examples)

    Table 82.1
    Dive Groups
    Forward or front (Group 1) A dive in which at takeoff the diver is facing the water with direction of rotation away from the board.
    Backward or back (Group 2) A dive where takeoff is from the end of the board with back toward water with direction of rotation away from the board.
    Reverse (Group 3) A diver has a takeoff facing the water, then using a forward approach rotates back toward the board.
    Inward (Group 4) The diver stands with back to the pool and rotates forward toward the board.
    Twisting (Group 5) A dive initiated by throwing one arm down and across the abdomen and one arm up and overhead and away from the body. Four types: forward, back, reverse, inward.
    Armstand (Group 6) A platform-only dive executed from an armstand position.

    Table 82.2
    Dive Body Positions
    Straight (Position A) A dive position in which the body is straight at hips and knees with feet together pointing down. The arm position can vary.
    Pike (Position B) A dive position in which the legs are straight, body is bent at the waist, feet together and toes pointed. Position of the arms can vary.
    Tuck (Position C) A diver’s body is bent at waist and knees bent with thighs drawn to chest and heels to buttocks.
    Free (Position D) Any combination of other positions and is restricted in its use in some twisting dives.

    BOX 82.1
    Examples OF Dives

    • A 5237D is a back dive with 1½ somersaults, 3½ twists, free position dive.

    • A 301B would be reverse dive, with a half-somersault in the pike position.

    • A 107B is a forward dive, with 3½ somersaults in the pike position.


  • Early roots in mid-1800s in Europe with “fancy diving,” where gymnasts performed acrobatics over water.

  • Springboard diving became an Olympic sport in 1904, followed by platform diving at the 1908 London Olympics.

Biomechanical Principles

  • Energy is transmitted along the kinetic chain from the hands, to the wrists, to the elbows, and to the shoulders.

  • The upper extremity absorbs most of the water-entry axial loading.

    • Shoulder is stabilized by elevating the shoulder girdle with increased scapular abduction, so the glenoid fossa is behind the humeral head and is better able to absorb axial load impacts.

    • Inadequate scapular abduction increases the demands on the soft tissue, causing injury, ligament laxity, and, in turn, shoulder instability.

  • Upon water impact, velocity is decreased by more than 50% within 1 second, with most injuries occurring during the first 600 ms and when the angle of water entry increases away from a vertical entry.

Competition Events

  • Springboard: 1 meter and 3 meters

  • Platform: 10 meters

  • High dive: 27 meters for males and 20 meters for females

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