INTRODUCTION

Swimming is traditionally known as a complete physical activity that serves the treatment of injuries, recovery of injured athletes, a way of overcoming stress. Nevertheless, those who swim four to eight kilometers daily, as swimming athletes do, know the other side of swimming. Who has not heard of swimmer's shoulder syndrome and other threats to these athletes' career success?

To understand the mechanisms that lead swimming athletes to suffer sports injuries, some knowledge of the anatomy of human body movement is required. Generally, injuries found in swimmers are the result of excessive repetition of stated movements. According to Brian J. Tovin of The Sports Rehabilitation Center, Atlanta, Georgia, ‘a competitive swimmer typically exceeds 4,000 strokes to one shoulder in a single workout, making this sport a common source of shoulder pathology’.(1) They originate mainly from technical failures, which forces us to constantly evaluate the biomechanics of swimmers in training for future precautions. According to McMaster (2), from the Department of Orthopedic Surgery at the University of California/USA, in a paper published in the journal Clinic Sports Medicine, ‘swimming activities have a low potential to injure practitioners.’ However, the doctor warns of the risks: ‘it is important to analyze the athlete's training in its entirety, identifying factors such as training load and program out of water’. Concerning non-athletes or master swimmers, there is a risk of factors related to age or technical inability, which will not be so present in young swimmers or athletes.

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Figure 1: The shoulder joint and its periarticular structures (3)

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ANATOMY OF MOVEMENT

As mentioned, competitive swimmers repeat moves excessively. Thus, the areas formed by mobile joints in the human body are subject to high suffering to the swimmer, particularly the shoulders and knees. No less problematic are the neck and back areas.

Movable joints, which can wear out due to overuse, must be understood. Its main elements are the joints themselves, the ligaments, and the tendons (Figure 1). Joint is the connection between two contiguous bones (neighbors, adjacent). Its structure is very varied, and the degree of movement that both bones can perform depends on it. The joint may allow for limited or variable-intensity movements. When the union is made by fibrocartilage, movement is limited, as in the case of the vertebrae. In the case of the knee and shoulders, for example, the bones are provided with a layer of cartilage on their joint surfaces and separated by a joint cavity. A series of ligaments prevent them from deviating from their relationship positions. The range of motion depends on the joint ends of the bones and the arrangement of the ligaments. The joint cavity is covered by the synovial membrane, whose cells secrete a fluid that fills the cavity and lubricates the surfaces in contact. Articular cartilage and synovial fluid make the friction of bones as they move minimally. Ligaments are masses of connective tissue in which the collagen fibers are highly reinforced and form very consistent bundles, arranged along lines of greater mechanical tension. They usually extend from bone to bone on both sides of the joints. Tendons are bands of connective tissue that connect muscles and can even penetrate the stiff part of the bone.

IDENTIFY ATHLETES AT RISK

An accurate diagnosis enables proper treatment and the swimmer's return to the water. Coach and athlete must discuss the problems together so that preventive measures, can be taken during training. ‘Careful monitoring of training volume, intensity, and duration by coaches and doctors will minimize overuse injuries and identify athletes at risk’, consider Rodeo (4) cited by Wanivenhaus et al. (5). In the case of pain reporting, a detailed history should be taken to determine the onset, duration, and specific movement related to the pain. The swimmer must be approached systematically for a check-up. Inspection and evaluation of the range of force movement and joint laceration help in diagnosing the problem.

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Figura 2: Rehabilitation and strengthening exercises for swimmers (8)

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THE CLASSIC "SWIMMER’S SHOULDER”

The term 'swimmer's shoulder' is not new, it was introduced back in 1974 by Kennedy and Hawkins (6) to describe a condition common among competitive swimmers, characterized by pain and dysfunction of the shoulder complex. (7)

According to MacMaster (2), 'the swimmer's shoulder is not a definable entity per se, the problem of shoulder pain in swimming athletes comes from a multitude of factors. The shoulder is an area reference of pain coming from several adjacent structures'.

As explained by Jimenez, cited by Rosa (8):

The shoulder joint is an unstable structure. The joint stabilization function is performed by joint ligaments and muscles. Arthritis in the scapula-humeral joint occurs when there is a partial stretch of this musculature, creating a joint fit arrangement and wear of the joint surface. All of this is associated with the swimmer's excessive use of articulation.

Microtraumas can occur when the shoulder joint is subjected to repetitive stimuli, as most of the propulsion in swimming comes from the arms. Changes in the angle of the swimmers' joint structures, were also observed. In some these changes do not cause problems, in others, it requires additional force to maintain joint stability. This new situation leads to fatigue and inflammation, or even pain, subluxation, or dislocation.

To prevent or rehabilitate the swimmer's shoulder syndrome we resort to the research of Kenal and Knapp (9). For them, the swimming mechanic must be revised. Crossing hands in front or maintaining a level position instead of rotating the body promotes mechanical limitation of the shoulder when in the extreme internal phase of rotation. Swimmers who constantly breathe on the same side should be encouraged to do bilateral breathing in practice. Other movements, such as pushing the pool wall to give impulses when using the swim kickboard is also not advisable because it causes mechanical limitation to the shoulder.

For those who have already been victimized by the swimmer's shoulder, we will recommend three rehabilitation exercises suggested by Kenal and Knapp (9). The exercises aim to strengthen the internal musculature of the shoulder and adjacent areas (rhomboid, trapezius). The 'reciprocal pulley' (Figure 2) consists of a cable with a holder at both ends, threaded through a small pulley. The patient holds one side with the hand referring to the diseased shoulder (in the case of our figure, the right side) while moving the opposite arm in an outward rotation.

Another interesting exercise that helps strengthen and stabilize the muscles in these areas is the 'alphabet bench press' (Figure 2). The patient lies on an inclined board, and with the shoulder flexed to 90 degrees and elbow extended, draws the alphabet with a hand weight (about two kilograms). With the help of the pulley attached to the wrist, resistance can be added to the exercise. Another tip from the Utah researchers: 'isometric and isotonic' (Figure 2). The patient holds the arm attached to the pulley isometrically in outward rotation while the scapula is retracted isotonically.

THE "BREASTSTROKER'S KNEE”

In breaststroke, swimmer's knee injuries are very common. The problem occurs in kick initiation, resulting from the alignment of the center of the knee to the center of the hip. Stress develops in the medial ligament and joint capsule. Exceeding the elastic range of the ligament, it may tear. Elite swimmers also have problems with the adductor musculature as a result of the type of contraction and the consequent tension held by the muscle. Just in this area, the meniscus, a fibrocartilage structure, can also be injured, with the combination of lateral flexion and torsion movements (in breaststroke). In these cases, the best way to prevent problems is with improved movement technique and proper training volume that does not overload the knees.

The incidence of the 'breaststroker's knee' in almost 80% of the athletes surveyed by professors at the Catholic University of Murcia, was verified in competitive swimmers of different levels. According to that research (10), the cause of the problem is, as always, the excessive repetition of a certain movement, in this case, a type of forced flexion used on the chest. The selected athlete recovers from pain during the propulsive phase of the leg, in which the hip flexion, abduction, and internal rotation position with the knee flexed and in external rotation is changed to a position of full extension, during the propulsion phase.

For the rehabilitation of the knees, we are turn back to the Utah/USA researchers (9), who will recommend strengthening the muscles of the hips and legs on a bicycle and in the leg press machine. While stretching exercises are not advised for injured shoulders, for the leg region they are relevant after bodybuilding sets, such as the hip flexor stretch (Figure 2).

OH...WHAT A PAIN IN THE BACK

Athletes in general, undergoing any strenuous activity need to strengthen their lower back, or the pain will appear. Inflexible back and legs and weak muscles in this region are the factors responsible for future problems. Any exercise that uses the extremities and requires trunk stabilization forces can be performed as the ‘back strength and stability’ exercise (Figure 2).

In the quadruped position, the patient first raises one arm and then the opposite leg. When accomplishing this without excessive trunk rotation, one can progress to the next step, elevating the arm and leg simultaneously. In an advanced stage, the patient can perform the same exercise performing stops with arms and legs in the air or even attaching weights on the extremities (wrist and shin).

FINAL CONSIDERATIONS

Several studies have examined the effect of shoulder syndrome and other threats to competitive swimmers' career success. This review presented a general panorama that deserves to be deepened, addressing epidemiology, that is, distribution, determining factors of injuries, damage to health, and finally, a proposition of specific measures to prevent, control, or eradicate the problems. (5,11,12)

Villanueva et al. (10), in their study with the breaststrokers, advise that prevention is the first measure to be taken and includes: a) correct execution of the swimming technique; b) stretching; c) weight training; d) early detection of fatigue; and e) preventive cryotherapy during competitions. The treatment of the pathology should include: a) stretching; b) technical correction of swimming; c) active rest, isolating the affected area with poly buoys; d) weight training; e) cryotherapy; f) application of ultrasound, and g) transcutaneous electrical nerve stimulation.

McMaster (2) explains that most injuries and illnesses found in swimming athletes are results of excessive repetitions, and their successful administration does not usually require surgical intervention. Rest and care to reduce inflammation should be tried. ‘It is important to understand that, while at rest or training less, every effort to keep the athlete in the water must be made, since the cessation of training, leads to a rapid process of loss of performance’, concludes the researcher.