Swimming
Introduction
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Swimming is the most popular aquatic sports discipline and is an important part of triathlon and water polo.
Epidemiology
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At the international level, swimming and the other aquatic sports disciplines are governed by the Fédération Internationale de Natation (FINA).
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USA Swimming registered 367,902 athletes and 3,096 clubs in 2014. Females made up 56.6% of year-round athletes, the majority of whose ages ranged from 10 to 14 years.
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US Masters Swimming consists of nearly 60,000 swimmers aged 18 years and older and provides support to more than 1,500 clubs and workout groups.
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US Synchronized Swimming oversees competitive events for synchronized swimmers who range in age from 12 to 20+ years.
General Principles
History
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Swimming has been a part of the Summer Olympic Games since its inception in 1896.
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Synchronized swimming was first introduced to the Olympics in 1948, but solo and duet competitions did not become official events until 1984. Team synchronized swimming was added in 1996.
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Open-water swimming became a part of the Summer Olympic Games in 2008.
Types of Sports or Races
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Freestyle events do not require a particular stroke, but 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.
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Backstroke events are performed in the supine position with alternating arm strokes and “flutter” kick ( ).
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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 ( ).
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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 ( ).
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Relay competitions typically consist of four swimmers. In a medley relay, each swimmer performs one of the four strokes.
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Synchronized swimming events can consist of solos, duets, teams of eight, and combinations of up to 10 swimmers.
Discussion of Sports-Specific Skills and Other Considerations
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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.
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Elite swimmers tend to be more flexible than their non-elite counterparts.
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Synchronized 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
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Speed is gained by decreasing drag/resistance while moving through the water.
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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.
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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”).
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Frictional drag is caused by the contact of the body surface with the water and is reduced by shaving and using specially designed swimwear.
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Technique and efficiency play a greater role than power in performance.
Equipment
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Goggles protect the eyes from chlorine and aid in vision underwater.
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Caps decrease resistance and keep hair out of the face.
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Kickboards can be held in the arms while practicing kick techniques.
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Fins are used to increase kick propulsion in practice.
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Hand paddles add resistance to the pull during practice.
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Pull buoys are placed between the legs while practicing pull techniques.
Safety Issues
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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.
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Sudden death in triathlon is most likely to occur during the swim. There is no clear association with skill level or medical problems. No athlete should swim without adequate supervision.
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Synchronized swimmers practicing boosts and throws are at increased risk of traumatic injuries including concussions.
Specific Training and Physiology Issues
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Although races typically range from 50 to 1,500 meters, practices can range from 3,000 to over 10,000 meters, which can predispose swimmers to overuse injuries.
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Several important physiologic changes occur with submersion in water.
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Gravitational blood pooling in the venous system is decreased, shifting fluids to the central circulation and pulmonary vascular system.
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Athletes with poor ventricular relaxation or increased pulmonary venous pressure may be at risk of swimming-induced pulmonary edema (SIPE).
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Overhydration prior to competition should be avoided.
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The parasympathetic nervous system is activated via the diving reflex.
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Heart rate is reduced, and vasoconstriction of muscle vasculature preserves blood flow to the brain and heart.
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These adaptive changes allow for increased time underwater without additional breaths.
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These changes can increase risk of arrhythmia and sudden death, particularly in athletes with long QT syndrome and/or paroxysmal atrial flutter or fibrillation.
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Prolonged breath-holding in synchronized swimmers can cause hypoxia and is often manifested by dizziness, disorientation, or even syncope.
Unique Environmental and Nutritional Issues
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Exercise-induced bronchospasm is prevalent in swimmers. Asthmatic children may be drawn to the sport by the warm, humidified air, but exposure to airborne chlorine may lead to airway inflammation and bronchoconstriction.
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Water immersion can expose athletes to a variety of dermatologic issues.
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Infectious conditions include:
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Swimmer’s itch (schistosome dermatitis): pruritic 3-5 mm erythematous papules in areas not covered by swimwear: lesions typically resolve spontaneously within 3–7 days
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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.
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Diving suit dermatitis: diffuse erythematous papules in areas covered by swimsuits caused by Pseudomonas
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Seabather’s eruption: 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 steroids
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Bikini bottom: firm, deep nodules along the inferior gluteal crease caused by Streptococcus or Staphylococcus aureus due to prolonged use of tight-fitting swimwear; best treated with systemic antibiotics and frequent warm soaks
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Swimmer’s ear
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Folliculitis
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Molluscum contagiosum
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Athlete’s foot, warts, and pitted keratolysis may also result from skin contact with pool decks.
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Contact dermatitis can occur from equipment or pool water. More severe forms include aquagenic urticaria, cold urticaria, and contact urticaria related to chlorine exposure.
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Copper-chelating shampoos and hydrogen peroxide are used for green hair caused by copper ions in pool water.
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Prolonged water exposure commonly leads to dry, itchy skin which is treated with application of petrolatum and avoidance of long, hot showers.
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Open-water swimmers are at increased risk of environmental injuries such as otitis, sunburn, jellyfish stings, dehydration, hypothermia, and hyperthermia.
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The necessity for revealing swimwear increases concern about body image and risk of disordered eating and relative energy deficiency, particularly in synchronized 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, and overuse 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 ( Fig. 82.1B ) and early to mid-pull ( Fig. 82.1C ) portion of the stroke. Poor body roll and unilateral breathing increase the propensity for impingement during freestyle.
Treatment: Includes avoiding the use of hand paddles
Return to Play: Emphasize lower extremity training, avoid strokes which 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 synchronized swimming and water polo ( )
Figure 82.2
Knee pain associated with kick.
Physical examination: 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 dolphin kick, as well as 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 above.
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’s maneuver), and reproduction of symptoms by placing the arm in hyperabduction and external rotation (Wright’s 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
General Principles
Diving is an aquatic sport distinct from swimming and has its own set of sports-specific injuries.
Statistics
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Approximately 12,000 athletes register with USA Diving each year.
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Typical age of Olympic-caliber divers: 12 years to mid-20s
History
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Springboard diving became an Olympic sport in 1904, followed by platform diving at the 1908 London Olympics.
Terminology
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Save: divers, in order to avoid a non-vertical entry, must save a dive, a position in which the body is thrust into hyperflexed shoulders and a hyperextended spine
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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
Biomechanical Principles
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Energy is transmitted along the kinetic chain from the hands to the wrists to the elbows and the shoulders.
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The shoulder absorbs most of the water-entry axial loading.
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Stabilizes the joint 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.
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Inadequate scapular abduction increases the demands on the soft tissue, causing injury, ligament laxity, and, in turn, shoulder instability.
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Upon water impact, velocity is decreased by more than 50% within 1 second.
Competition Events
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Springboard: 1 meter and 3 meter. Platform: 10 meter
Equipment
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Pool with adequate depth; having a dark-colored bottom pool or a water surface agitator (bubbles) can help the diver visualize the surface. The water surface agitator can also reduce the axial load energy from water entry.
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Dry-land equipment: trampolines with spotting rigs, landing pits, spotting harnesses, and poolside diving boards
Injury Patterns During Different Diving Components
Takeoff
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Phases: approach, hurdle (jump onto end of board), and press (depression of board and upward acceleration of body). Timing is essential for maximal acceleration of body and efficient press.
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Injuries during takeoff: patellar tendonitis, quadriceps tendonitis, patellofemoral compression syndrome, Achilles and posterior tibialis tendonitis, and lumbar injuries due to compensatory hyperextension
Flight or Midair Maneuver
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Begins when a diver leaves the board or platform and ends with initial contact with water
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Injuries during takeoff:
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Spine and long head of biceps injuries due to torsional overload during twisting
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Can strike the board mid-air, particularly the head, causing concussions and/or lacerations
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Only two reported fatal head injuries, and both occurred from the 10 meter platform during a reverse
somersault tuck dive attempt.
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Entry
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Most injuries occur during water entry due to forces upon entry and during underwater maneuvers as diver attempts to have a splashless entry ( Fig. 82.5 ).
