I INJURY CLINIC

Sports Medicine 13 (I): 58-70, 1992 0112-1642/92/000-0058/$06.50/0 © Adis International Limited. All rights reserved. SPOl77

Overuse Injuries in Adolescent Athletes Seamus E. Dalton North Sydney Orthopaedic and Sports Medicine Centre, Sydney, Australia

Contents 5 59 59 60 60 63 63 63 64 64 64 64 65 65 66 67 67 68

Summary

Summary I. Participation 2. Incidence 3. Types of Injuries 4. Growth 5. Risk Factors 5.1 Intrinsic Factors 5.1.1 Anatomical Considerations 5.1.2 Physiological Factors 5.1.3 Psychological Factors 5.2 Extrinsic Factors 5.2.1 Training Schedule 5.2.2 Sporting Equipment 5.2.3 Sporting Environment 6. Diagnosis and Treatment 7. Rehabilitation 8. Prevention of Injury 9. Conclusion

As sports participation increases so too does the incidence of injuries, both acute and overuse. The growing skeleton is particularly susceptible due to the presence of growth cartilage at 3 locations; the epiphyseal plate, the joint surface and the apophysis. The risk of injury is most pronounced during the rapid growth spurt of adolescence when other factors, such as muscle tightness across joints, also become important in the aetiology of sporting injury. Overuse injuries seen in this age group may reflect the growth characteristics of the immature skeleton or may be of the type seen in adult athletes undergoing rigorous training schedules. Recent developments in organised competitive sport have seen growing individuals undertake prolonged and intensive training programmes when they are particularly at risk of sustaining an overuse injury. The training programme is one of a number of risk factors important in the generation of injury, many of which can be modified or controlled to an extent. Other factors such as growth deformities or malalignments are peculiar to the individual and preparticipation evaluation of the young athlete helps to identify those at risk. Whilst long term disability rarely eventuates, the loss of enjoyment and temporary incapacity resulting from this type of injury is significant. It is apparent that many of these injuries are preventable, and given the information available concerning the factors involved in their aetio-

Overuse Injuries In Adolescents

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logy, it is the responsibility of coaches and health professionals alike to become involved in their early diagnosis, treatment and prevention.

1. Participation The extent of adolescent involvement in organised competitive sport is difficult to determine but it has been estimated that 50% of males and 25% offemales aged between 8 and 16 years in the US take part in organised competitive sport (Stanitski 1989). Another report suggests that in the US the number of children participating has doubled over the last 20 years and that one-third of the participants are female (Mueller & Blyth 1982). This increase in female participation has been particularly dramatic. In most Western countries organised sports programmes exist at the secondary school level. In some countries the emphasis on sport may be greater than others and in the present socioeconomic climate there appears to be a definite trend to encourage the successful adolescent athlete to achieve more and more goals through increased training and commitment. With these developments we are seeing young athletes consistently training harder and longer. Gymnasts may train 3 hours per day, young athletes may run up to 100km per week in training, and we have seen children running full marathons. Of 5807 starters in the 1981 Big M Marathon in Melbourne, 190 were children aged between 7 and 17 years. One 7-year-old completed the race in 3 hours and 31 minutes and a 13-year-old ran a time of 2 hours and 55 minutes. Young swimmers train for many hours and can carry out half a million swimming strokes per arm per year. Given these figures it is not difficult to understand how readily overuse injuries can occur in this age group, especially since gymnasts and swimmers often commence supervised training at 6 years or less.

2. Incidence The epidemiological studies reported in the literature vary significantly in terms of population studied, methodology and types of injuries re-

ported. Orava et al. (1981) reported on exertion injuries in female athletes, 60% occurring in girls aged 12 to 19 years. Tursz and erost (1986) reported on 789 sports-related accidents in children aged 0 to 15 years. Several school-based studies have looked at sports injuries in general, in children of all ages (Backx et al. 1989; Watson 1984). Other studies have been sport-specific or clinical case series (Nathan et al. 1983). In short, few of these studies have looked specifically at the adolescent population and the incidence, risk factors and types of overuse injuries seen. Therefore there are limited data available with which to truly assess the incidence and effects of overuse injury in the adolescent population. Several studies have reported on the incidence of acute, chronic and overuse injuries in the preadolescent and/or adolescent population. Garrick and Requa (1978) found that the incidence of sporting injury in a high school population of 3000 students was 39.3 per 100 athletes, 40% of which were referred to a physician. Other studies have looked at the incidence of injury in a particular sport (Walsh et al. 1985), but it is only recently that researchers have been able to document data reporting the incidence of overuse injuries in this younger population. Orava and Puranen (1978) reported on a series of 147 cases of exertion injuries in athletes aged 15 years or less. 90% had been training for over I year, the majority (65%) in track and field athletics. About one-third of the injuries were growth disturbances or osteochrondroses seen in other children, 50% were typical overuse injuries that affect adult athletes and 15% were anomalies, deformities or earlier osteochondritic changes which first became symptomatic during exercise. Kannus et al. (1988) reported a 30-month prospective follow-up study of athletic overuse injuries in children aged 15 years or less. It was noted that 32% of all boys' overuse injuries were classified as exercise-induced growth

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disorders and osteochondritic pains compared with only 15% of girls' injuries. A study carried out by the author at a sports clinic in Cambridge, England, found that of 139 sports-related injuries in children aged 9 to 16 years, almost 50% were overuse-type injuries directly related to training or sports participation (table I) [Dalton & Lachmann 1986]. During the same period of 29 months, 2274 injuries were seen in the clinic, the younger age group representing about 6% of the total injuries seen. Larson (1973) reported that of 4854 injuries on the athletic file at the University of Oregon Orthopaedic and Fracture Clinic, 19% (933) were in patients aged 15 or under and almost 15% of these involved the epiphysis. Many studies have been school based and have therefore reported a different injury profile to other studies that have been clinic based. The persistent overuse injury tends to present more to the treating physician, unlike some of the minor acute injuries that may be readily treated by rest and minor rehabilitation. Indeed, in some of these studies diagnosis and treatment was carried out by a nonprofessional (Backx et al. 1989). It is therefore difficult to truly assess the incidence of adolescent overuse injuI"Y. given the type of data available and the differences between the populations studied. The purpose of the Cambridge study was to determine what proportion of adolescent injuries presenting to a sports clinic were of the overuse type. It does appear that although many of these injuries are relatively minor, they represent a significant problem for growing athletes.

3. Types of Injuries Overuse injuries in a growing population can be roughly divided into 2 groups: those injuries that tend to be only seen in the young athlete, that is, injuries that reflect the growth characteristics and immature skeleton of the adolescent; and those injuries that are also found in the skeletally mature adult population. The former type of injury may represent both the most and least potentially disabling type of injury. Injuries to the growing and

immature skeleton can have long term effects and in the most severe cases can lead to permanent disability, examples being osteochondritis dissecans affecting the elbow of a young gymnast or baseball pitcher, or an injury to the upper femoral epiphysis. On the other hand, in many cases the overuse injury may simply reflect the manifestation of 'growing pains' seen in a normal growing population: for example, Osgood-Schlatter's, which becomes self-limiting and responds well to a reduction in sporting activity and relative rest coupled with a suitable flexibility programme. Osgood-Schlatter's and Sever's disease and iliac crest apophysitis are examples of growth-related disorders presenting as injuries in athletically active adolescents (Clancy & Foltz 1976; O'Neill & Micheli 1988). Patellofemoral arthralgia (chondromalacia patellae, patellofemoral stress syndrome, etc.) is a clinical syndrome that has been reported as a common cause of knee pain in adolescent athletes and the growth factor appears to be important in its aetiology. In the Cambridge study it was found that patellofemoral arthralgia represented 17% of overuse injuries seen in this age group (Dalton & Lachmann 1986). Other injuries such as stress fractures and tendinitides are found in the adolescent population, and, as in the adult population, they represent the results of repeated microtrauma to the musculoskeletal system. There appears to be an increasing prevalence of these overuse injuries, although to what extent this is a reflection of increased sports participation or increased awareness, and therefore earlier diagnosis, is difficult to determine.

4. Growth Growth is a normal process which occurs at a varying rate during a child's development. At different stages there is an increase or decrease in the velocity of growth, one such growth spurt occurring in adolescence, usually between the ages of 13 and 15 years. This adolescent growth spurt represents the development of skeletal maturity and tends to occur approximately 2 years earlier in girls than in boys. It is also known that some physical

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Table I. Types of sporting injuries in children aged 9 to 16 years seen by the author at a sports clinic in Cambridge, England

Overuse-type injuries Patellofemoral arthralgia Achilles tendinitis Infrapatellar tendinitis Osgood Schlatter's Tendinitis/tenosynovitis other sites Rotator cuff tendinitis Enthesopathies Lateral epicondylitis Osteochondritis/epiphysitis Stress fractures (metatarsal) Others Total Nonoveruse injuries Knee ligament sprain Ankle sprain Muscle strains Contusion/haematoma Wrist sprain Meniscus injury Foot strain Acute rotator cuff strain Others Total

No. of injuries

% of total

24

17.3

6 6 4

4.3 4.3 2.9 6.5 2.2 4.3 1.4 2.9 1.4 2.2 49.7

8 3 6 2 4 2 3 69

17 13 16 7 2 3 4 2 6 70

activity is needed for normal bone growth and development, and it is therefore the balance between the amount of physical activity and the stress resistance of the growing bone which to some extent determines whether or not some injuries occur (Malina 1969; Roy et al. 1985). Although many of the overuse injuries seen in the adolescent athlete are similar to those seen in the adult who has been subjected to repetitive overactivity, there are a group of injuries unique to the growing individual. Some of these appear to be growth disorders seen in nonathletic individuals which may become symptomatic during exercise; for example, osteochondritis of the femoral condyle. Others appear to be injuries to the growing bone itself in response to the repetitive microtrauma of sports participation, and a further group of injuries result from malalignments and muscletendon imbalances occurring during the growth process.

12.2 9.4 11.5 5.0 1.4 2.2 2.9 1.4 4.3 50.3

Growth cartilage features at 3 locations; the epiphyseal plate, the joint surface itself, and the apophyseal insertion of the musculotendinous unit to bone. There is some evidence that growth cartilage is less resistant to stress, either acute violent forces or repetitive microtrauma, than adult cartilage (Aegerter & Kirkpatrick 1975; Bright et al. 1974; Dugdale & Barnett 1986; Outerbridge 1984). Certainly it is well documented that significant macrotrauma applied to the ends of the long bones of the child will more likely result in an epiphyseal plate injury than a ligament disruption (Larson & McMahan 1966; Salter & Harris 1963; Speer & Braun 1985; Wilkins 1980; Zito 1983). The epiphyseal growth plate has several features, both anatomical and biomechanical, which make it susceptible to injury. The nature of the injury varies with age, growth rate and in the presence of a disease process. The epiphyseal plate is not a flat surface and has small central and peri-

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pheral contours which provide some resistance to shear forces. The increased height with age of these bony prominences coupled with the reducing height of the growth plate itself seems to influence the type of epiphyseal plate injury seen in younger and older children. Salter type I injuries occur more frequently in the· younger child due to the increased growth plate height and reduced height of these plate contours (Salter & Harris 1963; Speer & Braun 1985). In the older or adolescent athlete, overuse injuries of the epiphyseal growth plate are uncommon, the most notable exceptions being at the medial epicondyle in 'Little League' elbow and the proximal humeral growth plate in 'Little League' shoulder. Roy (1985) also reported on 21 young gymnasts with probable stress-related changes at the distal radial epiphysis related to their chosen sport. The incidence of involvement of the epiphysis or physis in sports-related injuries in children varies from 6% to 18% (Garrick & Requa 1978; Larson & McMahan 1966; Mueller & Blyth 1982), but a study of growth plate injuries at the University of Arizona Hospital in Tucson found that 42% of growth plate injuries were related to team or play activities (Speer & Braun 1985). The majority of these were acute injuries resulting from macrotrauma but this study highlights the susceptibility of the growth plate to injury. Whilst some disorders of growth plate cartilage are seen in the normal adolescent population, there appears to be a direct correlation between overuse and the development of breakdown at the articular surface of the adolescent athlete. Osteochondritis dissecans of the capitellum represents another clinical feature of 'Little League' elbow, and it has been postulated that this disorder results from the repetitive valgus strain applied to the pitching elbow. Osteochondral lesions are also seen at the hip, knee and ankle and may well develop in response to repetitive microtrauma, although the aetiology of many of these lesions remains unclear. In one review of juvenile osteochondritis dissecans of the knee, patients were found to be no more athletic than a large control group of subjects (Mubarak &

Sports Medicine 13 (1) 1992

Carroll 1981). The onset of symptoms mayor may not be related to athletic involvement. Apophyseal avulsions are occasionally seen in this age group at the attachment of large muscles such as the rectus femoris and hamstrings. These sites also appear to be susceptible to repetitive microtrauma (Godshall et al. 1981; Roy et al. 1985), and although this is seen less often at the epiphyseal plate, traction apophysitis is frequently seen in active adolescents. This represents an inflammatory process resulting from repetitive tiny avulsions and secondary healing occurring at the apophysis (Micheli 1987). Although less common, a major avulsion can occur at the apophysis as the end-stage of this repetitive process, an example being the medial epicondyle avulsion seen in a young baseball pitcher. Probably the largest group of adolescents with overuse injuries are those who have developed their symptoms and condition as a result of the effects of the normal growth process itself, namely, the muscle-tendon imbalances that occur across the joints of growing individuals. The prevalence of this type of problem is hard to accurately determine as many children with symptoms of pain or discomfort, previously termed 'growing pains', never present to a physician or sports injury clinic as their symptoms respond rapidly to rest and activity modification. As part of the normal growth process the elongation of the musculotendinous units occurs as a secondary response to the increase in length that takes place in the long bones at their growth plates. During phases of rapid bone growth, such as the adolescent growth spurt, this creates tightness and inflexibility across the joints as the lengthening of the musculotendinous unit lags behind that of the bone itself. This inflexibility creates imbalances across the joints, and during sports or play activity increased stresses are applied to both the joints and the attachments of the musculotendinous units themselves (Burkett 1970; Ekstrand & Gillquist 1983; Micheli 1986). The presence of malalignments such as coxa vara or valgus deformities of the knee, foot or ankle, increases,the likelihood of such imbalances occurring, thereby rendering the individual more susceptible to injury

Overuse Injuries In Adolescents

from repetitive microtrauma. These factors increase the likelihood of the growing individual developing a traction apophysitis such as OsgoodSchlatter's or Sever's disease, but can also give rise to pain from joints such as the patellofemoral articulation where it has been postulated that muscle imbalances about the knee give rise to relative lateral deviation and subsequent deformation of the patella (Ficat & Hungerford 1977; Outerbridge 1984). Pre-existence of excessive foot pronation or genu valgum further increases this risk, and the higher incidence of chondromalacia patellae in women is perhaps a reflection of an increased Qangle at the knee due to the increased pelvic diameter, especially during the pubertal growth spurt (Goodfellow et al. 1976). Most of these 'injuries' settle with a reduction in stress applied, restoration of muscle flexibility and the slowing of the growth process. Preparticipation evaluation of adolescent athletes is an important factor in detecting those individuals at risk due to alignment disorders and poor flexibility and plays a major role in the prevention of injury.

5. Risk Factors Various factors appear to be involved in the aetiology of overuse injuries in the adolescent. Recent interest in this area of sports medicine has helped to identify a number of risk factors, which if addressed correctly by the athlete, his or her coach, parents, treating physician and physiotherapist, can certainly minimise the effects of overuse injury as well as prevent their occurrence. Some of these factors are intrinsic; that is, they are a reflection of the individual and mayor may not be subject to change. Others are extrinsic and may be modified more readily. 5.1 Intrinsic Factors 5.1.1 Anatomical Considerations Reference has already been made to the growth characteristics of the adolescent in terms of biological age, the presence of growth cartilage and its susceptibility to injury. Physical maturity is there-

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fore a major factor in determining an individual's ability to withstand the repetitive stresses of athletic training or sports participation. Another major factor is the presence of anatomical malalignments which commonly occur in a growing population. Femoral neck anteversion is frequently seen in the adolescent and has an important role in the development of several overuse injuries seen in young ballet dancers. Here, in an attempt to improve turn-out restricted by hip movement, the dancer may exaggerate lumbar lordosis, increasing the likelihood of stress fractures of the pars interarticularis. They may also increase external tibial rotation with pronation of the foot, magnifying the risk of development of patellofemoral symptoms (Micheli 1986). Patella alta, genu valgum and excessive foot pronation are all malalignments associated with the development of patellofemoral pain. Indeed, girls have been reported as developing patella alta as a result of the adolescent growth spurt (Micheli & Smith 1982; O'Neill & Micheli 1988). The effects of some of these conditions can be partially reduced by orthotic correction. Muscle flexibility as a risk factor in overuse injuries has been mentioned, but more importantly it is any imbalance between muscle flexibility and strength in different muscle groups which predisposes the individual to injury. Lysens et al. (1989) developed accident-prone and overuse-prone profiles for young athletes and reported that a combination of muscle weakness, ligamentous laxity and muscle tightness predisposes to stress injuries. They also reported that these overuse effects are increased by large bodyweight and length, a high explosive strength, and malalignment of the lower limbs. While muscular strength increases with growth there are several factors which need to be taken into consideration. Firstly, there may be a relative reduction in strength as well as agility, endurance and coordination with rapid growth spurts (Stanitski 1989). Secondly, imbalances across joints can occur as a result of uneven flexibility and strength in different muscle groups, seen particularly in the young sports specialist such as the runner with

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strong quadriceps and triceps surae but relatively weak hamstrings. It is also seen in the swimmer with strong shoulder elevators and medial rotators but poor scapular retractors and shoulder external rotators, thereby increasing the risk of symptomatic instability and tendinitis about the shoulder. Thirdly, there may be an increase in the incidence of certain types of injuries seen as an individual's strength and speed increase, although they tend to be of the acute type (Davidson et al. 1979; Lysens et al. 1989).

5.1.2 Physiological Factors There is increasing evidence that the decreased bone density found in amenorrhoeic female athletes predisposes to the development of overuse injuries, particularly stress fractures (Lloyd et al. 1986; Nelson et al. 1987). Menarche may be delayed in young female athletes undertaking a vigorous training programme, thereby potentially increasing their risk of developing stress fractures, although this has been questioned (Malina 1983; Malina et al. 1979). This is of particular relevance to the young female ballet dancer, gymnast or endurance runner. Tanner's staging of genital development (Tanner 1962), the date of menarche or secondary sexual development (Shaffer 1980) can all be used to determine skeletal maturity, and this is important in the preparticipation evaluation of the young athlete if mismatching of individuals within sports programmes is to be avoided. Matching the individual with an appropriate sport is as important as matching one adolescent athlete against another in a competitive, especially contact, situation. Size alone may not be a true representation of the muscle bulk (as opposed to fat) of the individual. It is widely accepted that deconditioning and poor preparation of the athlete increases the risk of overuse injury, and a training and participation schedule appropriate to the child's degree of preparation is essential if injuries are to be kept to a minimum. Some studies have shown alarming increases in the prevalence of obesity in school-age children in the United States and this is perhaps a reflection of changes in twentieth century Western

Sports Medicine 13 (1) 1992

society, both in terms of recreational activities and diet (Gortmaker et al. 1987).

5.1.3 Psychological Factors During childhood, and particularly adolescence, emotional and psychological factors may playa role in the development of sporting injury. Various reports have alluded to the high risk-taking behaviour of adolescents and the effect that this has on the incidence of sporting accidents (Lysens et al. 1989; Padilla et al. 1976). In the case of overuse injuries the psychological characteristics of an individual will to some extent determine the degree of sporting involvement, commitment, carefulness, awareness of other risk factors, sociability and response to peer and parental pressure. Lysens et al. (1989) also comment on psychological traits such as psychosomatic lability and hypochondriasis, which are important in determining an individual's response to an overuse injury. It should be noted that in the adolescent, psychological disturbances may manifest as physical symptomatology. 5.2 Extrinsic Factors 5.2.1 Training Schedule

Probably the most important and perhaps the most correctable risk factor in the development of overuse injuries in all ages is training error. Any training schedule should be appropriate for the individual and take into account many of the other risk factors such as growth characteristics, skeletal maturity and anatomical malalignments. The intensive training schedules designed for adult athletes are not appropriate for the adolescent, who is not a 'little adult'. Unfortunately, community awareness is often poor, and excessive demands placed upon the adolescent athlete by a poorly designed pre- and in-season training programme often result in overuse injuries. Training programmes should be individualised according to skeletal maturity and degree of preparedness. Various reports have looked at the benefits of strength training in the prepubescent and adolescent, and it has been suggested that concentration on skills training and technique would be most ap-

Overuse Injuries In Adolescents

plicable during the growth spurt (Legwold 1982; NSCA 1985). Some sporting bodies have laid down guidelines for the training of these athletes, and adherence to these schedules may help to reduce the risk of injury. The American Academy of Pediatrics (1982) suggested that under no circumstances should a full marathon be attempted by immature youths, and in the United States the Little League Baseball Association has limited to 6 the number of innings that young players can pitch in a week. Adherence to these guidelines is largely the responsibility of the coach in the case of supervised or organised sport. However, these latter guidelines have been questioned by Francis et al. (1978) who, in their roentgenographic survey of 398 former Little League participants, concluded that participation in organised baseball as an adolescent had no enduring deleterious effect on the throwing elbow. Close attention to faulty technique and excessive loads applied to the growing skeleton is of paramount importance for all coaches and trainers involved in adolescent sports programmes. In racquet and throwing sports technique has a significant bearing on the development of overuse injury. For example, the pitcher in Little League baseball is subjecting the elbow and shoulder, and hence the humeral epiphyses, to considerable stresses and attention to throwing technique is important in the prevention of injury. Modification of an activity, such as the 2-handed backhand in tennis, may help to reduce the stresses applied to the upper limb. Coaching errors can contribute to the generation of sporting injury. This may be due to nonrecognition of appropriate sports techniques, especially in throwing or contact sports, an inability to recognise injuries, ignorance of rules appropriate to the adolescent, or unrealistic expectations. Parental influence can also contribute to excessive demands being placed on the adolescent. This often results from a strong wish for their child to succeed, partly due to the parents' own goals and ambitions, but also because of the increasing rewards associated with success from competition in sport such as tennis where young elite players can earn large sums of money. Sport should be a plea-

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surable pastime for the child or adolescent and the extent of their involvement should not compromise their enjoyment or physical health in the pursuit of other goals determined by supervising adults. 5.2.2 Sporting Equipment Appropriately fitting individual equipment is essential for all sports, both for adequate protection and also to prevent injury. Often junior teams have makeshift equipment which may be of poor quality and ill-fitting, and in the case of protective gear this can predispose to injury, usually acute. Footwear needs to be well-fitting with an appropriate sole, both in terms of shock-absorbtion and flexibility at the forefoot, a firm heel counter and the addition of orthotic support to correct malalignments such as excessive pronation. It should also be remembered that children are often encouraged to play in bare feet which may predispose to injury. The incidence of overuse injuries in the adolescent runner such as patellofemoral arthralgia, iliotibial band friction syndrome, shin splints, stress fractures, achilles tendinitis and Sever's disease, correlates to some extent with footwear appropriate to the individual and their chosen sport. Appropriately sized bats and racquets are important in upper limb sports, as are the size and weight of footballs in kicking sports. It is also interesting to note that often the poorer quality, ill-fitting equipment is given to the less skilled participant who may well be the poorly prepared, less conditioned player that needs greater protection. 5.2.3 Sporting Environment The association between playing surface and athletic injury is well accepted, either in the case of rigid surfaces such as concrete floors in aerobic gymnasiums, or in situations where athletes have switched surfaces from outdoors to an indoor artificial surface. Close attention to these changes and the shock-absorption qualities of particular surfaces will help to prevent injury. However, Garrick et al. (1986) found that the brand of shoe and the type of flooring did not influence injury rates in aerobic dancers. They did, however, suggest that

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Sports Medicine 13 (1) 1992

further investigation is required to properly assess these and other variables.

6. Diagnosis and Treatment Successful treatment of the injured adolescent requires a good understanding of the particular characteristics of the growing individual. During the assessment of the individual much information can be gained which will ultimately influence diagnosis and treatment. In the case of acute injuries, diagnosis is often self-evident, but overuse injuries frequently present with pain as the major symptom, often in the absence of obvious physical findings. The history should include details of the extent of sports participation, recent growth spurts, family history, previous injuries as well as any recent changes in equipment, training schedule or the level of competition. Clinical examination needs to encompass a detailed assessment of any underlying malalignments, joint laxity or musculotendinous inflexibility. Strength imbalances may exist, particularly after recent injury or with sport-specific training schedules, and this is often seen in the lower limb, particularly between flexor and extensor muscle groups. Whilst physical manifestation of microtrauma is often limited to paint, the individual must be closely examined for areas of point tenderness, especially over the epiphyses and apophyseal tendon attachments. Joint motion, both passive and active, needs to be assessed, and an examination of the hip joints in the adolescent or child should be mandatory when assessing lower limb pain. Any child with a limp or knee pain has a hip disorder until proven otherwise. A missed femoral epiphyseal injury or hip joint disorder can be potentially disastrous for the adolescent. Whilst most significant overuse injuries present with pain to the physician, many symptoms following repetitive submaximal sporting trauma remain unreported, as these conditions respond to rest and are therefore readily self-limited. Tendinitis, apophysitis and epiphyseal overuse injuries presenting to the physician are usually evident on clinical examination. However, some disorders such

as patellofemoral arthralgia present with minimal physical findings other than the malalignments and muscle-tendon imbalances that have contributed to their development. Osteochondritis dissecans, especially of the knee, frequently exists with little evidence of joint tenderness or swelling, and radiological investigation is required to confirm the diagnosis. It is therefore the close understanding of the growth characteristics of the athlete coupled with an appropriate index of suspicion which uncovers many of these clinical conditions. The concept of relative rest and activity modification is an important one and is particularly relevant in the treatment of these injuries. Many can be treated symptomatically whilst attention is paid to prevention of recurrent injury. Injuries such as stress fractures and the tendonitides frequently require enforced periods of rest from aggravating activity, often for set periods in order to allow adequate time for healing and resolution of inflammation. However, many growth-related disorders such as Osgood-Schlatter'S can be reasonably managed whilst allowing resumption of activities that do not aggravate symptoms. In the elite or high-level athlete, prevention of deconditioning is important and aerobic fitness can be maintained using nonweightbearing activities such as swimming and cycling during the treatment and recovery phase of lower limb injuries. Also muscle stretching and strengthening programmes can be continued. The duration and extent of rest required varies from individual to individual, and these treatment programmes need to be tailored to each athlete. One study looking at 68 athletes presenting with Osgood-Schlatter's disease found that the pain caused complete cessation of training for an average of 3.2 months and the disease interfered with fully effective training for an average of 7.3 months (Kujala et al. 1985). The mainstay of treatment is relative rest whilst all attempts are made to maintain some level of aerobic conditioning. During the treatment and rehabilitation phase attention should be paid to correction of muscle imbalances in strength and flexibility. Correction of muscle imbalance about the shoulder is important in the treatment of glenohumeral instability and

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Overuse Injuries In Adolescents

more particularly rotator cuff disorders in the swimmer or racquet-sport player. Overuse back problems seen in adolescents include stress fractures of the pars interarticularis, osteochondritis of the vertebral body end-plates, and the more commonly posterior element mechanical low back pain aggravated by a hyperlordotic posture. Correction of inadequate pelvic tilt control, poor posture and hamstring and hip flexor instability, coupled with abdominal strengthening, are an integral part of an effective treatment programme for these conditions. Immobilisation has sometimes been used in the treatment of specific conditions such as lower limb stress fractures, and whilst this is still occasionally required it is no longer considered appropriate treatment for Osgood-Schlatter's disease where it results in weak and tight musculature about the knee. Antilordotic bracing should be considered for pars interarticularis stress fractures remaining symptomatic despite rest from sporting activity (Micheli 1980). Ice in the initial stages and antiinflammatory medication given later can be used in the reduction of pain and inflammation. Corticosteroid injections are rarely indicated in adolescence. Anterior knee pain presenting in the adolescent athlete is a symptomatic condition often given the misleading label 'chondromalacia patellae', suggesting that definite pathology exists at the patellofemoral joint. Various names have been given to this condition where pain appears to be originating from the patellofemoral articulation: these include the terms patellofemoral arthralgia, patellofemoral stress syndrome and 'headache of the knee' (Ficat & Hungerford 1977; Goodfellow 1984; Sandow & Goodfellow 1985). Exclusion of other causes of knee pain is important before the institution of a multifaceted treatment programme designed for each individual. Conservative treatment includes restoration of hamstring and quadriceps flexibility, balanced training of the knee extensor mechanism, particularly with regard to vastus medialis function, orthotic correction of excessive pronation at the foot and ankle, and the use of proprioceptive

taping to assist in correction of tracking anomalies of the patella at the knee. Surgery is not usually required in the treatment of the overuse injury. However, arthroscopic intervention needs to be considered in the treatment of osteochondritis dissecans lesions of the knee and elbow; the age, size and looseness of the lesion often determining whether or not it is removed or internally fixed.

7. Rehabilitation An adequate rehabilitation programme for each injured athlete is an essential part of their treatment, and in the case of overuse injuries where rest has been the major treatment approach this has particular relevance in returning the individual to sport. During the rest phase of treatment a degree of deconditioning takes place and muscles frequently become weaker and tighter. Restoration of muscle balance, flexibility, aerobic and anaerobic conditioning is needed. Ankle injuries are common in the child, adolescent and adult, and rehabilitation is often neglected. It is important for the athlete and coach to realise that proprioceptive retraining may be needed about the ankle when there has been a period of immobilisation. Many children and adolescents pay scant attention to the need for adequate restoration of biomechanics and conditioning before a return to sport. Their impatience may be compounded by peer or parental pressure to return to their normal training schedule. A supervised rehabilitation programme is essential in order to prevent a recurrence of injury, and such a programme becomes the responsibility of the coach as much as the treating physician and physiotherapist. Normal joint motion in the presence of normal strength and flexibility is required before resumption of training and normal endurance should be the goal before a return to competition.

8. Prevention of Injury Prevention of recurrent injury in the adolescent should be addressed in the rehabilitation phase of -their treatment programme. However, it should be

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the aim of those sections of the medical, paramedical and coaching community involved in youth sports to try to prevent these injuries from developing. Preparticipation evaluation has a major role to play in this regard, and early identification of those risk factors apparently involved in the aetiology of overuse injury can help. Many of the extrinsic factors become the responsibility of the coach or trainer or even parent who directly determines equipment, footwear, playing surface, but more importantly training schedules. Intrinsic factors such as growth disorders and anatomical malalignments require clinical assessment for their identification. In the United States mandatory medical examination prior to sports participation exists in many States although the appropriateness of this generalised assessment has been questioned (Stanitski 1989). Where a particular sport or coaching body insists on preparticipation evaluation, early identification of those individuals at risk through poor preparation, underlying skeletal immaturity, growth disorders and musculotendinous imbalances can take place. However, in most schoolbased sports such evaluation programmes do not exist and it becomes the responsibility of the athlete's parents or coach to seek such an assessment of the child or adolescent. Identification of sport-specific risk factors is also possible in preseason evaluation. Steele and White (1986) attempted to identify injury proneness in gymnasts, concluding that girls with poor musculature, short stature and a hyperlordosis are particularly prone to injury. Bond et al. (1988) investigated the relationship between psychological profiles and injury rate in elite swimmers and, surprisingly, found a trend for swimmers with more effective attentional profiles to sustain more injuries. Structuring of suitable intervention programmes has obvious implications for possible injury prevention. Education programmes directed at the community provide a means of alerting coaches and parents to the hazards of inappropriate sporting participation by the adolescent and help them in the early identification of athletes at risk (McKeag 1985). It is important for coaches and athletes alike

Sports Medicine 13 (J) 1992

to understand the need for a specialised approach to training in the adolescent. Flexibility trainingshould be the basis of most training and treatment protocols for the growing athlete, and care needs to be taken with strength training (Brady 1982; Ryan & Salciccioli 1976). It may be appropriate to reduce the training intensity during periods of rapid growth in order to prevent injury, and plenty of warm-up and cool-down stretching is important, Various recommendations have been made regarding strength training and the increase in intensity in aerobic training. An increase in duration and intensity of training of 10% per week is reasonable, and in strength training, adult supervision is important and the emphasis should be on high-repetition, low-resistance with no maximal lifts allowed (Legwold 1982; Rooks & Micheli 1988).

9. Conclusion For generations children have enjoyed the freedom of play and sporting pursuit, but recent years have seen sport become more organised and competitive for all ages. Much has been written about the physiological and anatomical development of the adolescent, and our understanding of growth disorders and possible injurIes to the immature skeleton has increased. However epidemiological data on the prevalence of overuse injury in the adolescent population is limited and until this becomes more available community awareness of the risks of intensive training during rapid growth periods may remain unstaisfactory. A different problem arises within the medical profession where a better understanding of the biomechanics and factors involved in the aetiology of overuse injury in the adolescent would improve not only detection of the injuries but also treatment and prevention. All too often a young athlete is told that nothing can be done for his or her condition until growth has all but ceased. Hopefully, some of the information now available will allow these individuals to return to sport sooner whilst also preventing these injuries occurring. Coaches and parents aJike have an important role to play in the prevention of injury, and education programmes coupled with

Overuse Injuries In Adolescents

suitable guidelines for children in sport are becoming increasingly desirable. In general, sports in which adolescents are involved are safe and many overuse injuries are minor. The majority of epiphyseal and apophyseal disorders do not give rise to long term disability and rarely result in growth deformities. The question of whether or not early stresses to joints predisposes to the development of secondary degenerative change remains unanswered, but it seems unlikely in the absence of actual pathological damage to the joint surface occurring during the growth period. So whilst prevention oflong term disability may only be a small part of our treatment goals, certainly restoration of function and a return to enjoyable activity is a priority.

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