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Coaches, athletes and parents can also use these pages to answer their questions regarding aquatic health issues.

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Preventing Injury: Young swimmers are not “little adults”

There is an adage in sports medicine that “the child is not simply a little adult”. And nowhere is this comment more relevant than in aquatic sport, in particular swimming, where training usually begins at an age before bones, muscles and joints have matured. If the progress of a young swimmer is too rapid, the training load too intense or poorly monitored, the risk of injury increases.

The sites in the growing skeleton where injury is more likely to occur are regions where tendons attach to “soft,” immature bone, and in growth plates located at the ends of each long bone. Coaches play an integral part in recognising the early indicators of injury and may intervene early by reducing the training load, altering stroke mechanics, or modifying weight training and dry land exercise programs.Overuse is the most common injury mechanism and the young swimmer is particularly prone to shoulder, low back and knee problems. Sports doctors recognise conditions such as "swimmer's shoulder," "butterfly swimmer's back", and  "breaststroker's knee". These apply equally to water polo players,

MUSCULOSKELETAL GROWTH AND DEVELOPMENT

Children possess a very unique musculoskeletal system. The explosive growth of long bones occurs at active sites of new bone formation and ceases when these growth plates or “epiphyses”, fuse. The timing of these events may vary but is usually complete by the late teens.

Other pre-adolescent sites of active growth include regions called “apophyses”, where tendons connect muscle to bone, and the sensitive “articular” cartilage that covers the ends of long bones where they meet to form a “joint.” Injuries involving these active areas of new bone and cartilage formation may disturb growth or disrupt normal joint movement resulting in permanent damage. A doctor should always investigate injuries to vulnerable sites of musculoskeletal growth in young swimmers.

To co-ordinate joint movement, muscle groups act in tandem. While one group lengthens the opposing or “antagonist” group shortens to provide controlled, smooth movement. Muscle balance is important around major joints and muscle imbalance may precipitate overuse injury. Strengthening growing muscles through graduated resistance exercises is beneficial provided an experienced coach acknowledges athlete growth and development.

MUSCULOSKELETAL INJURY

The benefits of regular physical activity during childhood far out-weigh the risks. The developing skeleton needs weight-bearing exercise to establish sound bone “architecture.” However the potential for injury must always be considered when working with young athletes. It is worth remembering that:

1) Injury can result from severe external forces causing serious impact damage or intrinsic repetitious stresses that result in overuse. Immature bone is resilient or “plastic” and therefore more likely to bend than to break. The term “greenstick” fracture is used to describe the incomplete break in the bone of a child.

2) Tendons provide the attachment between muscle and bone while ligaments support joints and usually connect bone to bone. They both consist of connective tissue and may undergo varying degrees of injury from repetitive use causing inflammation (“tendonitis”) to complete rupture. Muscles have a much better blood supply than either ligaments or tendons and therefore they tend to heal more quickly.

3) Traction injuries are common in young athletes where tendons are more likely to pull away from their bony attachment rather than tear or rupture. Common sites of traction injury include the front of the knee where the strong quadriceps tendon attaches and the back of the heel where the Achilles tendon inserts.

Prompt recognition and accurate diagnosis of injury means that most athletes require little more than conservative treatment and rest. Adolescent overuse or repetitive stress may seem trivial but has the potential to become chronic. Young bodies heal quickly with the correct treatment and careful supervision and disruption to normal activity is usually minimal.

SPECIFIC SITES OF SWIMMING INJURY

1) The shoulder

Of all the joints in the body, the shoulder is the most mobile and is capable of an extraordinary range of movement due to its “ball and socket” design. The "rotator cuff" muscles maintain the ball in the socket and provide additional stability. Overhanging the shoulder joint is the end of the clavicle or “collar bone” beneath which sits a soft, fluid-filled cushion or bursa. The "rotator cuff" muscles are important in stabilising the shoulder and they frequently bear the repetitive stress of the freestyle and butterfly arm action.

"Swimmer's shoulder"

This is the name given to a condition associated with pain felt at the front of the shoulder and often provoked by training. It may begin with an irritating "niggle" associated with exercise, or progress to persistent resting pain. It reflects chronic irritation of one or more of the tendons or muscles around the shoulder resulting from repetitious swim stroke action, calculated by some authorities as about two million per year in a competitive swimmer. The tendons of the rotator cuff, especially supraspinatus, are commonly inflamed causing pinching or “impingement” in the shoulder.

The treatment of swimmer’s shoulder includes identifying the specific action that provokes pain, altering training and in some cases, technique. Swimmers should continue with kicking drills, non-aggravating strokes and dry land workouts. The assessment of swimming technique may involve the use of video analysis to correct any possible causes.

Treatment by physical measures includes "ice massage" to the shoulder immediately after training and physical therapy modalities including ultrasound. Anti-inflammatory medication to reduce the pain and inflammation may be helpful. These medications should only be taken under medical supervision and should not be used to mask persisting symptoms or encourage a premature return to training.

Where conservative measures fail, orthopaedic intervention may include localised injections of corticosteroid. In some chronic cases surgery is necessary to relieve pressure on swollen tendons.

But the best method to overcome the problem of "swimmer's shoulder" is to recognise the early signs, make necessary technical changes, take rest, consult medical support staff and prevent the symptoms from worsening.

2) The knee

The knee joint is the next most common site of injury in swimmers. The unique kicking actions in breaststroke, water polo and synchronised swimming are a frequent cause of knee pain from repetitive overuse.

Unlike the shoulder, the knee is a "hinge joint" with a restricted range of movement in one plane. The tibia (shin bone) articulates with the femur (thigh bone) to constitute the knee joint. Four strong knee ligaments provide additional stability and overlaying this are the strong quadriceps muscles on the front of the thigh and the hamstrings behind. Also in front of the knee joint, sits the patella or “knee cap” surrounded by the quadriceps tendon that glides in a groove on the front of the femur and represents an important biomechanical relationship for knee extension.

"Breaststroker's Knee"

The specific “whip kicking” action of breaststroke is considered as the most likely cause of this problem comparable to the "egg beater" kick used by water polo players and synchronised swimmers. Repetitive stretching of the ligament or muscle attachments on the inner side of the knee causes localised pain that in some cases may be complicated by damage to the internal knee cartilages or “menisci”.

It soon becomes evident to any athlete with chronic knee pain that continuing aggravation is not an option. Rest from the offending kicking action is essential but the swimmer may maintain fitness through other strokes or "arms only" and "pull-buoy" drills. Ice massage and physical therapy modalities are often successful in moderating acute knee pain and anti-inflammatory medication is indicated with the usual caution. The need for surgery in these cases is not commonly indicated unless some internal damage to cartilage has been identified.

Anterior Knee Pain

There are a number of other causes of pain in the front of the knee of the young swimmer that should be excluded in the diagnostic process.

These include problems associated with abnormal "tracking" of the kneecap causing pain by repetitious movements of the kicking pattern of all four strokes. Swimmers frequently describe pain when they sit for long periods (also known as "movie-goer's knee") or when they descend stairs or slopes.

Treatment may begin with specific exercises to correct the pull of the quadriceps muscles. External forms of bracing have their place but provide little more than temporary relief if the main cause is not addressed. Symptomatic relief may also be obtained from the use of ice massage, physical therapy or anti-inflammatory drugs.

Another cause of adolescent knee pain involves the attachment of the ligament of the kneecap into the front of the shin. This represents a traction injury to the immature site of tendon attachment into bone.

3) The lower back

Many sports place recurrent, stressful demands on the low back that may damage “soft tissues” or even cause stress reaction in bone resulting in “fatigue” fractures.

Strokes requiring repetitive hyperextension (back arching) or explosive synchronised swimming routines may cause low back problems. Rapid rotation increases the risk of damage. Expert coaching is important, particularly in the young swimmer whose bones and muscles are immature.

"Butterfly swimmer's back"

The butterfly stroke demands repetitive low back hyperextension. This action, repeated many times in training is accentuated during breathing and arm recovery. Many young butterfly swimmers are troubled by chronic backache that may be caused by stress on a variety of structures including muscles, ligaments, the developing vertebrae or the inter-vertebral discs. Chronic low back pain in an adolescent athlete should always be fully investigated to exclude the potential for long-term damage to active growth sites. Physicians may confirm their diagnostic suspicions through plain X-rays or more sophisticated high tech imaging including CT and MRI.

Rehabilitation of the "swimmer's back" demands a multidisciplinary approach with contributions from coach, physical therapist and physician. Posture, hamstring tightness, trunk mobility and lumbar spine stability must be assessed. Strengthening and stabilisation techniques are helpful. Where injury to bone is suspected, close medical scrutiny is recommended.

KEY POINTS

- Musculoskeletal overuse is a risk for the young aquatic athlete.
- Potential sites of stress in swimmers include shoulders, knees or low back.
- Training load, poor stroke mechanics and disregard for early signs of overuse contribute to delayed recovery.
- Injuries to young athletes demand thorough medical examination and full investigation.
- Rehabilitation may necessitate rest, however modified activity is often an option.
- The long-term wellbeing of the young swimmer must remain the prime consideration.
- The benefits of regular exercise far outweigh the risk of injury.

*David F. Gerrard MD
Vice Chairman FINA Sports Medicine Committee
Professor of Sports Medicine, University of Otago, New Zealand
Olympic swimmer and Commonwealth Games gold medallist
Chair, Drug-Free Sport NZ
Chair WADA Therapeutic Use Committee
New Zealand Olympic Team Physician and former Chef de Mission

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