Stress injury of the distal radial growth plate

Abnormal Wrist Sagittal Kinematics in Gymnasts With Dorsal Wrist Pain: A New Syndrome

BACKGROUND

The pathology of dorsal wrist pain in gymnasts without abnormal radiographic findings remains unclear.

PURPOSE/HYPOTHESIS

The purpose of this study was to identify abnormal wrist sagittal kinematics in gymnasts with dorsal wrist pain. It was hypothesized that gymnasts with dorsal wrist pain would show abnormal sagittal kinematics with reversible hypermobility of the intercarpal joint.

STUDY DESIGN

Controlled laboratory study.

METHODS

Participants included 19 wrists in male gymnasts with dorsal wrist pain, 18 wrist in male gymnasts without wrist pain, and 20 adult men without a history of wrist pain. Magnetic resonance imaging (T2-weighted sagittal images) findings at 0°, 30°, 60°, and 90° of wrist extension were used in kinematic analysis. The angles and translations of the radiolunate, capitolunate, and third carpometacarpal joint were measured and compared between the 3 groups.

RESULTS

At 90° of wrist extension, gymnasts with dorsal wrist pain had a significantly lower radiolunate joint angle (28.70°± 6.28° vs 36.19°± 7.81°; P = .020) and a significantly higher capitolunate joint angle (57.99°± 6.15° vs 50.50°± 6.98°; P = .004) and distal translation (1.17 ± 0.50 mm vs 0.46 ± 0.62 mm; P = .002) than gymnasts without dorsal wrist pain.

CONCLUSION

Gymnasts with dorsal wrist pain showed abnormal wrist sagittal kinematics. These novel findings may facilitate understanding of dorsal wrist pain, which can be recognized as a new syndrome termed "gymnast's lunate dyskinesia."

Inconsistencies and Imprecision in the Nomenclature Used to Describe Primary Periphyseal Stress Injuries: Towards a Better Understanding

Stress injuries involving the epiphyseal-physeal-metaphyseal complex affecting the extremities of child and adolescent athletes were first described in the early 1950s. Initially observed in Little League baseball players, these injuries are now known to affect skeletally immature athletes in a variety of sports that involve high-impact repetitive overuse activities. Collectively known as primary periphyseal stress injuries, they may affect the long bones around the shoulder, elbow, wrist, hand, hip, knee, ankle, and foot of young athletes. These injuries respond well to timely treatment and relative rest, while non-compliance with non-operative treatment can produce skeletal growth disruption and resultant limb deformity. A major concern raised from the existing literature on primary periphyseal stress injuries is the long history of inconsistent and imprecise terminology used to describe these injuries. A variety of terms have been used to describe primary periphyseal stress injuries, including those which potentially misinform regarding who may be affected by these injuries and the true nature and pathophysiologic mechanisms involved. These imprecisions and inconsistencies arise, at least in part, from a misunderstanding or incomplete understanding of the nature and mechanism of primary periphyseal stress injuries. In this article, we examine the inconsistent and imprecise nomenclature historically used to describe primary periphyseal stress injuries. We also offer a novel framework for understanding the pathophysiologic mechanisms behind these injuries, and provide suggestions for more standard use of terminology and further research moving forward.

Primary Periphyseal Stress Injuries in Young Athletes: A Systematic Review

BACKGROUND

Overuse injuries are common in sporting children and adolescents. These injuries are a particular concern when they involve the epiphyseal-physeal-metaphyseal (EPM) complex given their potential to disturb skeletal growth. Specifically, the limits of mechanical tolerance of the EPM complex to repetitive stress may be exceeded by the intense and continuous training characteristic of many youth sports today.

OBJECTIVE

This article describes the present status of knowledge on the occurrence and outcome of primary periphyseal stress injuries (PPSIs) affecting the EPM complex in the extremities of children and adolescents involved in youth sports.

METHODS

A comprehensive review of the sports medicine literature was conducted to determine the nature and extent of PPSIs affecting the EPM complex of the extremities among youth sports participants and the potential for consequent skeletal growth disturbance and resultant limb deformity associated with these injuries.

RESULTS

Our initial search uncovered 128 original published scientific articles reporting relevant data on PPSIs. There were 101 case reports/series, 19 cross-sectional, 1 case-control, and 7 cohort studies with relevant data. The case reports/series studies reported 448 patients with PPSIs involving the extremities. Children and adolescents representing a variety of high impact repetitive youth sports activities-including baseball, badminton, climbing, cricket, dance, gymnastics, rugby, soccer, swimming, tennis, and volleyball-may sustain PPSIs involving the shoulder, elbow, hand and wrist, knee, and ankle and foot. Although incidence data from prospective cohort studies are lacking, data arising from cross-sectional studies suggest that PPSIs may be common in select groups of youth athletes-including the shoulder in baseball players (0-36.6%), wrist in gymnasts (10-83%) and platform divers (52.6%), and fingers in rock climbers (5-58%). Notably, not all stress-related skeletal changes detected on imaging were symptomatic in these studies. When diagnosed and treated with an appropriate period of rest and rehabilitation, most patients studied were able to return to their sport activities. However, our data also show that 57/448 PPSIs (12.7%) produced growth disturbance, and that 28/448 patients (6.2%) underwent surgery for their injuries. Absence of treatment, delayed presentation and diagnosis, and non-compliance with a rest regimen were common in cases that produced growth disturbance.

CONCLUSIONS

PPSIs may affect the extremities of children and adolescents engaged in a variety of youth sports, especially at advanced levels of training and competition. Most skeletally immature patients with PPSIs respond well to timely treatment; however, in extreme cases, PPSIs can progress to produce skeletal growth disruption which may necessitate surgical intervention. Clearly, establishing the early diagnosis of PPSIs and providing timely treatment of these injuries are needed to ensure the skeletal health of youth sports participants. Rigorous prospective longitudinal epidemiological and imaging studies designed to provide incidence rates of PPSIs and to determine the effect of PPSIs on long-term skeletal health are also necessary.

The Effects of Endurance Sports on Children and Youth

In the United States, youth participation in sports continues to increase yearly. This increase in participation, in conjunction with the trend toward early sports specialization and year round training, has led to a similar increase in athletically developed injuries. These injuries vary in nature and acuity, with the type of injury often related to the athlete's age, sport, and level of training. Endurance athletes are at an elevated risk of injury as they frequently push their body to the limit during their arduous training. Pediatric endurance athletes can be particularly vulnerable, especially to overuse injuries, given their unique and ever-changing physiological state. It is important to understand the specific challenges facing not only the physical, but also the emotional well-being of these pediatric endurance athletes to maximize performance while minimizing injury and potential long-term sequelae.

Continued growth after limited physeal bridging

BACKGROUND

After any physeal injury, the primary concern is the possibility of some pattern of growth alteration, particularly transphyseal bridging that may cause lasting deformities and impact subsequent patient care. Small areas of physeal bridging, however, may be associated with continued growth, rather than impairment.

METHODS

Seven patients with small central physeal bridges of the distal femur were identified. Demographic data and imaging studies were reviewed.

RESULTS

Radiography identified small, relatively centrally located transphyseal osseous bridging that was associated with a linear (longitudinal) region of osseous density extending from the physeal bridge proximally into the metaphysis. This linear striation disappeared at the metaphyseal/diaphyseal gradation, an area of progression proximally from metaphysis to diaphysis. Only 1 patient had a significant leg length inequality. Magnetic resonance imaging confirmed the intrametaphyseal linear sclerotic bone and its disappearance with diaphyseal remodeling.

CONCLUSIONS

Small, central transphyseal osseous bridges may form after radiologically confirmed acute physeal injury. Normal physiological (hydrostatic) growth forces can be sufficient to overcome such limited central bridging and allow continued, essentially normal, longitudinal growth.

LEVEL OF EVIDENCE

Level IV (retrospective case series); anatomic study.

Lower extremity overuse injuries in pediatric athletes: clinical presentation, imaging findings, and treatment

Paralleling the growing popularity of organized sports among pediatric athletes, the stress and intensity of training regimens has escalated the frequency and severity of pediatric overuse injuries. It is essential that radiologists have a thorough knowledge of the pathogenesis of these injuries and of their characteristic patterns with different imaging techniques in order to appropriately diagnose overuse injuries in the pediatric skeleton. Knowledge of the classification, mechanism, clinical and imaging manifestations of acute and chronic overuse injuries of the lower extremities common among pediatric athletes can assist in imaging-based diagnosis and characterization of injury.

Physeal injuries in children's and youth sports: reasons for concern?

A systematic review of the literature on the frequency and characteristics of sports related growth plate injuries affecting children and youth in organised sport was carried out. Both acute and chronic physeal injuries related to participation in sports have been reported to occur, although injury incidence data are somewhat limited. Of particular concern is the growing number of stress related physeal injuries, including those affecting the lower extremities. Although most physeal injuries appeared to resolve with treatment and rest, there is also evidence of growth disturbance and deformity. Possible injury risk factors and countermeasures are discussed, and suggestions for directing future research provided.

Imaging of upper extremity stress fractures in the athlete

Although it is much less common than injuries in the lower extremities, an upper extremity stress injury can have a significant impact on an athlete. If an accurate and timely diagnosis is to be made, the clinician must have a high index of suspicion of a stress fracture in any athlete who is involved in a throwing, weightlifting, or upper extremity weight-bearing sport and presents with chronic pain in the upper extremity. Imaging should play an integral role in the work-up of these patients; if initial radiographs are unrevealing, further cross-sectional imaging should be strongly considered. Although a three-phase bone scan is highly sensitive in this regard, MRI has become the study of choice at most centers.

Physeal Widening in the Knee Due to Stress Injury in Child Athletes

OBJECTIVE

The objective of our study was to describe the MRI appearance of and possible mechanism responsible for physeal widening in the knees of high-level child athletes.

CONCLUSION

Widened physes in the knees of skeletally immature child athletes have MR signal characteristics similar to the normal physis but likely are a sign of stress injury. These children should cease the offending sport and rest the knee to allow rapid healing.

Wrist pain, distal radial physeal injury, and ulnar variance in the young gymnast

In gymnastics, the wrist joint is subjected to repetitive loading in a weightbearing fashion. In this setting, chronic wrist pain is quite common. Because gymnasts ordinarily enter the sport at very young ages and train for several years before skeletal maturity is attained, the growth plates of the wrist are at risk for injury. In addition, imaging studies have identified evidence of injury to the distal radial physis and the development of positive ulnar variance. Recent studies provide more information on the relationships between these findings, as well as factors that may predispose some gymnasts to wrist pain. This article provides a comprehensive review of these issues and offers suggestions for management, preventive measures, and future research.

Upper Extremity Stress Fractures

Although less common than lower-extremity stress fractures, upper-extremity stress fractures are becoming recognized much more frequently. A majority of these fractures are caused by overuse and fatigue of the surrounding musculature and, as a result, may be prevented by appropriate training and conditioning. Diagnosis is made by history and physical examination with the aid of plain radiographs, bone scans, and MRI. Most of these fractures heal with a period of relative rest followed by a structured rehabilitation program. A small percentage of these fractures, however, may require surgical fixation. The present article reviews the different types of upper extremity and torso stress fractures seen in athletes, starting with the sternum and extending outward to the fingers. The presentation, diagnosis, mechanism of injury, treatment, prevention, and prognosis for each of these injuries will be discussed.

Stress-induced Salter-Harris I growth plate injury of the proximal tibia: first report

We describe a case of chronic Salter-Harris I injury of the proximal tibial epiphysis. To our knowledge such an injury has not been described in the English language literature. The radiological appearance can mimic chronic infection. The possibility of chronic athletic stress-related change should be considered in such scenarios to avoid a misdiagnosis.

Effect of a prophylactic brace on wrist and ulnocarpal joint biomechanics in a cadaveric model

BACKGROUND

Wrist pain from repetitive dorsiflexion and compression during pommel horse exercises is common among male gymnasts.

PURPOSE

To determine the biomechanical effects of a prophylactic wrist brace on the wrist and ulnocarpal joints during mechanical loading in a cadaveric model.

HYPOTHESIS

The lateral wedge of the palmar pad of the brace will compensate for positive ulnar variance, distributing contact forces more evenly across the radioulnar carpal joint.

STUDY DESIGN

Controlled laboratory study.

METHODS

Six male and six female fixed cadaveric forearm-wrist specimens were subjected to a 32.13-kg compressive load applied through the long axis of the pronated forearm with a dorsiflexed wrist in contact with a support surface. Wrist joint dorsiflexion angle and ulnocarpal joint intraarticular peak pressure were assessed under three brace conditions: Ezy ProBrace with and without palmar pad and a nonbraced control.

RESULTS

Wrist joint dorsiflexion angle was significantly reduced by the Ezy ProBrace with and without the palmar pad. However, ulnocarpal joint intraarticular peak pressure was reduced only by the brace with pad.

CONCLUSION

Prevention of pathologic wrist changes requires intervention in pressure attenuation, which was achieved with the Ezy ProBrace with palmar pad.

CLINICAL RELEVANCE

This brace may decrease the cumulative effects of repetitive stress of pommel horse exercise training.

Stress fractures of the upper extremity

Stress fractures are common injuries in the athletic population. Although much of the published literature has focused on lower extremity stress injuries, these injuries also occur in the upper extremities. Stress injuries of bone result from repetitive loads smaller than would be required to cause an acute fracture. As bone is repetitively stressed, it behaves like any solid substance. If deformity occurs within its elastic range, it returns to its original configuration. If stressed into its plastic range, permanent deformity occurs, and microfractures propagate, causing structural failure and complete fracture of the involved bone. High clinical suspicion is required for diagnosis because of historical and physical features can be vague. Plain radiographs are often inconclusive, but bone scans and MR imaging usually help elucidate the diagnosis. Most upper extremity stress injuries will heal with nonoperative management. In rare situations these injuries can progress to nonunion, which requires surgical correction.

Deformation and vascular occlusion of the growing rat femoral head induced by mechanical stress

To investigate the effects of mechanical stress on the extent of deformation and decrease of the blood supply to the femoral head in the growing rat, we conducted a histological and microangiographic study, using a custom-made hip-joint loading device. Application of a 1-kg to 3-kg load to the hip joint caused compression not only of the articular cartilage but also of the growth plate of the femoral head. These changes were particularly prominent in the lateral portion of the femoral head. The compression also caused complete occlusion of the lateral epiphyseal arteries, representing the blood supply to the femoral head, at the point of penetration into the epiphyseal cartilage. Our results indicate that the sum of forces during mechanical load application to the hip joint in growing rats acts to deform the cartilage of the lateral side of the femoral head. Our results also indicate the presence of a mechanically weak point in the femoral head which may lead to occlusion of the lateral epiphyseal arteries.

Salter-Harris III stress fracture of the proximal first metatarsal: a case report

An intraarticular, dorsal, proximal epiphyseal stress fracture (Salter-Harris III) of the first metatarsal was identified in a 14-year-old boy. Successful fracture healing was achieved with a rocker sole shoe modification and activity limitation.

Pressure mapping of the radioulnar carpal joint: effects of ulnar lengthening and wrist position

The purpose of this study was to investigate the effects of ulnar lengthening and wrist position on force transmission through the radioulnar carpal joint in a forced dorsiflexed wrist position. Eight cadaveric arms were subjected to a 30 kg compressive load directed down the forearm towards the wrist. A pressure sensor recorded forces across the wrist joint with the triangular fibrocartilage complex intact and excised. The biomechanics of the distal radioulnar joint were altered by changes in ulnar length and wrist position. Pressures at the ulnolunate articulation increased as the ulna was lengthened and were significantly lower when the triangular fibrocartilage complex was excised. An inverse relationship between triangular fibrocartilage complex thickness and ulnar variance was shown. Greater increases in ulnolunate pressure were observed in more positive ulnar variant wrists.

Distal radial growth plate injury and positive ulnar variance in nonelite gymnasts

To assess the prevalence of stress injury to the distal radial growth plate and of positive ulnar variance in a nonelite gymnast population, we administered a radiographic survey and questionnaire to 44 skeletally immature nonelite gymnasts (27 girls and 17 boys). The subjects trained an average of 11.9 hours per week. Radiographic findings consistent with stress injury of the distal radial physis were found in 25% (11 of 44) of participants. Ulnar variance was found to be more positive in the gymnasts when compared with age-predicted norms. An average side-to-side difference in ulnar variance of 0.9 mm was observed. Radiographic findings of stress injury to the growth plate and the amount of ulnar variance were not associated with age, sex, training intensity, wrist pain, height, or weight. There was also no significant relationship between ulnar variance and radiographic findings. The mean ulnar variance in nonelite gymnasts was between that measured for elite gymnasts and nongymnasts. These results indicate that stress injury of the distal radial growth plate occurs in a significant percentage of nonelite gymnasts. It also appears that ulnar variance is more positive than would otherwise be predicted, suggesting growth inhibition of the distal radius, a growth stimulation of the ulna, or a combination of both.

Stress fracture of the scaphoid combined with the distal radial epiphysiolysis

A stress fracture of the scaphoid combined with distal radial epiphysiolysis occurred in a 16 year old badminton player. Repeated shearing and torsional forces by excessive wrist movement from hitting a shuttle probably cause stress injuries in both the scaphoid and the distal radius.

Physique as a risk factor for ulnar variance in elite female gymnasts

The aims of this study were: 1) to determine ulnar variance variability of elite, female gymnasts; 2) to evaluate the relationship between ulnar variance and physique, maturity status, and training characteristics of these gymnasts. All 156 skeletally immature female gymnasts were participants at the World Championships Artistic Gymnastics, Rotterdam, The Netherlands, in 1987. Chronological ages varied between 13.1 and 20.6 yr (mean = 15.9 +/- 1.3 yr). A large set of anthropometric dimensions was taken and somatotype was determined by the Heath-Carter technique. Skeletal age was assessed by the Tanner-Whitehouse II method. Menarcheal status and training data were collected by questionnaire. Ulnar variance was determined according to Hafner et al. Gymnasts differ significantly from reference girls with respect to physique and maturational status: gymnasts were smaller and delayed in skeletal maturity with about 1.5 yr. For those who had attained menarche, mean age at menarche was 15.1 +/- 1.3 yr. Ulnar variance shows a normal distribution in the gymnasts, ranging from -10.5 mm to +5.9 mm, which is somewhat more positive, i.e., an ulnar overgrowth, than reference wrists. The relationship between ulnar variance and somatic and maturational features suggests that female gymnasts who are more mature and have a physique characterized as relatively tall with a high lean body mass are at greater risk for developing a positive ulnar variance. No relationship between ulnar variance and training characteristics was evident. It is concluded that the observed positive ulnar variance in this sample of elite female gymnasts is less pronounced than originally stated in most "case reports."

Radiology of sports-related injuries

Participation in organized sports and fitness activity continues to increase in the United States. As a result, more acute bone and soft-tissue injuries are occurring in this patient population. Chronic overuse syndromes are also more common today. It is important for radiologists to understand the mechanism of injury so that they can properly approach the imaging of these patients. Although magnetic resonance imaging (MRI) is frequently the technique of choice, other imaging methods are also important and may, in certain cases, be preferred to MRI. In this review, we discuss extremity injuries by anatomic region. The spine is not included. A tailored imaging approach to each anatomic region and type of injury is discussed.

Factors associated with wrist pain in the young gymnast

We conducted a cross-sectional survey of 52 nonelite gymnasts (32 girls, 20 boys; average age, 11.8 years) to assess their history of training and wrist pain within the last 6 months. An intensity index was created using the number of training hours per week and the athletes' skill levels. Wrist pain was prevalent in 38 (73%) of the gymnasts. Gymnasts with wrist pain were older (12.6 years versus 9.7 years; P = 0.0002), trained more hours per week (13.5 versus 7.7; P = 0.0002), trained at a higher skill level (P = 0.01), and began training at an older age (7.0 years versus 5.1 years; P = 0.006). Analysis of intensity versus age suggested that a threshold of training intensity may be important in the development of wrist pain. Logistical regression found these factors to be independently associated with wrist pain: intensity (P = 0.036), age > 10 years (P = 0.018), age < 14 years (P = 0.016), and the age of initiation of training (P = 0.020). This study demonstrates that wrist pain is a common problem among nonelite young gymnasts. Training intensity, relative to the age of the participant and the age when training was initiated, appears to be an important determinant of the development of wrist pain in this population.

Physical activity and bone mass: exercises in futility?

Growing bone responds to low or moderate exercise through significant additions of new bone in both cortical and trabecular moieties and results in adaptation through periosteal expansion and endocortical contraction. Intracortical activation frequency declines in growing bone in response to exercise, reducing porosity and the remodelling space. These adaptations can be maintained into and throughout adulthood. Young bones have a greater potential for periosteal expansion than aging bone, allowing them to adapt more rapidly and efficiently to an acute need for increased strength, but a threshold level of activity exists above which some bones respond negatively by suppressing normal growth and modelling activity, reducing geometric, mechanical and material properties in cortical and trabecular bone. From cross-sectional studies, differences in bone mass between exercising and non-exercising adults are generally less than 10%, but do not account for exercise history which may be very important, and often fail to consider important confounding variables. There is sufficient longitudinal data to demonstrate that moderate to intensive training can bring about modest increases of about 1-3% in bone mineral content (BMC) of men and premenopausal women. In young adults very strenuous training may increase BMC of the tibia up to 11% and its bone density (BD) by 7%, but may represent periosteal woven bone formation in response to excessive strain. Some evidence shows that exercise can also add bone mass to the post-menopausal skeleton, although the amounts are site-specific and relatively modest. Increases as high as 5-8% can be found after 1-2 years of intensive exercise, but additions of bone to the femur and radius are generally less than 2%, well within the range of the remodelling space and measurement precision. Although increases in bone mass of the post-menopausal skeleton may be extremely modest, physical activity is important to preserve bone mass and muscle function. Detraining reduces any bone mass increase to pre-existing values so that long-term benefits are only retained with continuing exercise. Most importantly, the amount of bone gain that can be achieved appears dependent primarily on the initial bone mass suggesting that individuals with extremely low initial bone mass may have more to gain from exercise than those with moderately reduced bone mass.

Stress changes of the distal radial growth plate. A radiographic survey and review of the literature

We conducted a radiographic survey to determine skeletal age and the nature and prevalence of stress-related changes affecting the distal radial growth plate in 60 young competitive gymnasts (39 females, 21 males). Comparison of results for chronological and skeletal age revealed a significant delay in maturation for girls (P less than 0.001). Radiographic evaluation revealed 5 gymnasts (4 girls and 1 boy) with stress-related changes of the left wrist, and four of these were considered to be minimal. These results, in conjunction with our previous findings and the review of related literature, reveal three important observations. First, the widening and irregularities of the distal radial physis that we described previously appear to be the first in a spectrum of abnormal changes secondary to overuse and probably represent a stress fracture of the distal radial growth plate. The radiographic changes associated with this injury are not the normal adaptive changes seen in young, competitive gymnasts. Secondly, more serious long-term abnormality may result even though the injury may initially resemble a Salter-Harris type I or II stress fracture. Long-term complications may include symmetrical or asymmetrical retardation or halted growth at the affected site, positive ulnar variance, and associated pathoanatomic sequelae. Thirdly, the incidence of distal radial growth plate stress injury remains unclear; we recommend a further, large-scale prospective epidemiologic study involving both male and female gymnasts. We urge that physicians and other health professionals associated with gymnastics clubs educate coaches about the possibility of significant injury to the distal radial physis, risk factors, and suggested preventive measures.

Gymnastic injuries

In the past 15 to 20 years gymnastics has become very popular. The increased participation exposes a greater number of athletes to potential injury. The risk of gymnastic injuries seems to be proportional to the level of the athletes; the higher the level of gymnastics, the more hours are spent in practice, with a greater exposure time. With the increased risk in gymnastics, the incidence of acute injuries will also increase, and as the skill level increases, the load during the workout will also increase, providing more opportunity for chronic injuries. As in many sports, the ankle is the most injured body part. Some injuries, however, seem to be specific to gymnastics. In gymnastics the upper extremities are used as weightbearing limbs, so high impact loads are distributed through the elbow and wrist joint. Back problems appear to result not only from single episodes of macrotrauma, but also from repeated microtrauma caused by specific impact loads during vaults and hyperextension. Early detection is the key to treating elbow, wrist and back pain in the gymnast. Reinjury following an acute injury may be reduced by allowing for complete rehabilitation before returning to full practice. Some studies indicate that maturation rate could play a potential role in injury predisposition. The combination of periods of rapid growth and intense training could provide for conditions where the gymnast is more injury prone.

Wrist loading patterns during pommel horse exercises

Gymnastics is a sport which involves substantial periods of upper extremity support as well as frequent impacts to the wrist. Not surprisingly, wrist pain is a common finding in gymnasts. Of all events, the pommel horse is the most painful. In order to study the forces of wrist impact, a standard pommel horse was instrumented with a specially designed load cell to record the resultant force of the hand on the pommel during a series of basic skills performed by a group of seventeen elite male gymnasts. The highest mean peak forces were recorded during the front scissors and flair exercises (1.5 BW) with peaks of up to 2.0 BW for some gymnasts. The mean peak force for hip circles at the center or end of the horse was 1.1 BW. The mean overall loading rate (initial contact to first loading peak) ranged from 5.2 BWs-1 (hip circles) to 10.6 BW s-1 (flairs). However, many recordings displayed localized initial loading spikes which occurred during 'hard' landings on the pommel. When front scissors were performed in an aggressive manner, the initial loading spikes averaged 1.0 BW in magnitude (maximum 1.8 BW) with an average rise time of 8.2 ms; calculated localized loading rates averaged 129 BW s-1 (maximum 219 BW s-1). These loading parameters are comparable to those encountered at heel strike during running. These impact forces and loading rates are remarkably high for an upper extremity joint not normally exposed to weight-bearing loads, and may contribute to the pathogenesis of wrist injuries in gymnastics.