|Minimising Injuries in Gymnastics Activities|
Injury is currently a cause of impaired performance for elite New Zealand gymnasts. Maintenance and improvement in gymnastics performance by reducing the risk of injury is desirable. This paper aims to a) outline the incidence and nature of gymnastics injury and the evidence in the literature for risk factors associated with gymnastics injury, and b) to outline a prospective study currently being conducted with elite New Zealand gymnasts to assess the relationship between injury risk during gymnastic competition and training, and physical and medical factors. Detailed gymnastics training and competing information, and injury report forms are collected. Musculoskeletal, psychological, medical and anthropometric screenings are conducted every three months. Preliminary results indicate that training and musculoskeletal variables are possible risk factors for gymnastics injury.
Keywords: Gymnastics, injury, risk factors.
Injury is currently a cause of impaired performance for elite New Zealand gymnasts. This paper aims to outline the incidence and nature of gymnastics injury and evidence in the literature for risk factors associated with gymnastics injury, and to outline a prospective study conducted with elite New Zealand gymnasts to assess the relationship between training, physical and medical factors and injury risk during gymnastic competition and training.
Injury Rate in Gymnastics: Table 1 compares injury rate data from studies that have included training/competition exposure time as the denominator. Differences in injury rates between the studies are most likely indicative of how an injury was defined within each study. If an injury is broadly defined as "any gymnastics-related incident that resulted in a gymnast missing any portion of a workout or competitive event" (Cain, Cochrane, Caine and Zemper, 1989, p.813) then the reported injury rate will tend to be higher than a study that narrowly defines an injury as a problem that was attended to by a physician (Snook, 1979).
For example, the study by Sands et. al. (1993) included very minor injuries, whilst Lindner and Caine (1990) carefully excluded injuries that gymnasts were able to 'work through' in training or competition. The problem with excluding less severe injuries is that many of the common gradual onset/overuse type injuries will not be reported. In order to reliably compare studies (both within and across sports), injury definitions must be standardised, and they must be sensitive enough to register the very common 'non-specific' overuse type injuries that gymnasts suffer regularly (McAuley, Hudash and Shields, 1987).
Reinjury: There is only one gymnastics epidemiological study describing the incidence rate of reinjury. The NCAA (1994) reported 2.2 reinjuries per 1000 athletic exposures for women, and 0.5 reinjuries for men. Caine et. al. (1989) expressed reinjury as a percentage of total injuries and found that 33% of all injuries were attributable to earlier occurrences of the same injury. The authors suggested that this figure indicates that gymnasts often return to training and competition before they are fully rehabilitated.
Practice vs. Competition: Data from studies investigating the proportion of injuries occurring in practice compared with competition have found that between 79% and 97% of injuries occur during practice (Pettrone and Ricciardelli, 1987; Kerr and Minden, 1988; Garrick and Requa, 1980; Lindner and Caine, 1990; Wadley and Albright, 1993; NCAA, 1994). However, when time spent competing compared with practising was accounted for, (i.e. exposure denominator data were included) it was found that the injury rate was three times greater in competition than in practice (NCAA, 1994). These data indicate that although most injuries occur during practice (due to spending more time practising than competing), the injury rate is greater in competition.
Injury Onset: The onset of sports injuries is typically categorised as being either gradual (overuse) or sudden (acute). Injury onset data from epidemiology studies, presented in Table 2, indicate that, with the exception of one study by Caine et. al. (1989), between 57% and 82% of injuries recorded in gymnastics were of a sudden nature. No explanation for this anomaly was cited by Caine et. al., however, the authors were uniquely thorough in ensuring all injuries were recorded. That is, injury data were gleaned from several sources including training diaries, coaches reports, onsite inspection by the primary investigator, and interviews with the athletes. This is in direct contrast with Sands et. al. (1993) who left the reporting of injuries completely to the athletes. Consequently, it is likely that the percentage of gradual onset injuries is reduced by negligent recording of 'non-specific' overuse injuries (McAuley et. al., 1987). In some cases, gymnasts perceive their overuse type injuries as being so common that they do not report them as injuries (Meeusen and Borms, 1992). The reporting of injuries is also influenced by how an injury is defined, and because, generally, no distinction is made for an acute injury that is superimposed on a chronic injury mechanism (Caine et. al., 1996).
Type of Injury: A comparison of injury type from prospective studies of women's competitive gymnastics (see Table 3) indicates that sprains (19% - 47%) and strains (6.4% - 35%) are consistently the most common type of injury to female gymnasts. A study of male gymnasts has also reported that sprains and strains are most common (NCAA, 1994). The high proportion of these injuries is not surprising given the highly repetitive nature of impacts associated with landings from dismounts, and during floor routines (Caine, Lindner, Mandelbaum, and Sands, 1996). The data in Table 3 are also influenced by injury definition and data collection methods. The high proportion of non-specific overuse type injuries in the study by Caine et. al. (1989) is indicative of their thorough injury recording methods, whilst the lower percentage of mild injuries reported by Wadley and Albright (1993) and Snook (1979) reflects that injuries for these studies were defined as problems presented to medical staff.
Location of Injury: A comparison of injury location data from prospective studies of female competitive gymnasts (see Table 4) indicates that the lower extremity was injured most often (54.1% - 70.1%), followed by the upper extremity (15.1% - 25%), and the spine/trunk region (7.5% - 16.7%). Of the lower extremity injuries, ankle injuries were most common, followed by the knee and then foot/toes. In the upper extremity, the wrist, elbow and hand/fingers were most often injured as a percentage of total injuries, and for the spine/trunk region, injuries to the lower back were most frequent.
For male gymnasts, there is evidence to indicate that along with a higher proportion of lower extremity injuries (36.4% - 43.1%), there is a higher proportion of upper extremity injuries (36.4% - 53.8%) when compared with women (Bak et. al., 1994; Weiker, 1995; Lueken, Stone and Wallach, 1993). In terms of specific body parts for the men, there were a large proportion of lower back, ankle, knee, wrist and, in particular, shoulder injuries. The high frequency of shoulder injuries in male gymnasts is most likely the result of extra physical demands placed on the shoulder area in events such as rings, pommel horse, and horizontal bar.
Head/Spine/Trunk: There is little doubt that, although not as common as lower extremity injuries, the severity of lower back problems in gymnastics is of considerable concern. Case-studies indicate that gymnastics lower back injuries tend to have a gradual onset (which may reduce the reported incidence of back problems), involving primarily advanced level gymnasts (Caine et. al., 1996). This implicates experience and competitive level as risk factors for injury. Common sites of lower back injury include vertebral bodies and intervertebral discs. Severe injuries include vertebral endplate abnormalities, and pars interarticularis damage with resultant spondylolysis (stress fracture) and spondylolisthesis (slipping of one vertebra onto another) (Caine et. al., 1996). The movements most likely to result in lower back injury are chronic repetitive flexion, extension and rotation demanded of the spine and its associated structures during gymnastics (Hall, 1986). In addition, the extreme loading forces resulting from dismount and tumbling landings place the spine and lower extremities under enormous stress (Caine et. al., 1996). This stress has been implicated in pars interarticularis spondylolysis and spondylolisthesis, and in the genesis of vertebral growth plate disorders which may disrupt growth and/or lead to chronic degenerative changes in the spine (Brukner and Khan, 1993).
Lower extremity: In gymnastics, the lower extremity, like the spine, is involved in absorbing large repetitive forces over a long period of time. The magnitude of these forces is approximately four times body weight (BW) for takeoffs (Takei, 1991), and 12 times BW for landings (Panzer, Wood, Bates and Mason, 1988). Data gleaned from prospective studies indicates that lower extremity injuries typically occur suddenly from a 'missed move' (Linder and Caine, 1990), and are most often ankle sprains, lower leg strains (Caine et. al., 1989) and knee dislocations (Linder and Caine, 1990). Lower extremity injuries with a gradual onset typically include ankle impingements (from chronic pointing of the foot), lower leg stress fractures and compartment syndromes (from the repetitive stress associated with landing), and patellofemoral knee problems (from biomechanically dysfunctional tracking of the patella) (Meeusen and Borms, 1992).
Upper extremity: Upper extremity forces have magnitudes of 1.5 times BW for vault, 3.9 times BW for horizontal bar, 9.2 times BW for rings, 2.0 times BW for pommel horse and 3.1 times BW for uneven bars (Caine et. al., 1996). Case and cross-sectional studies indicate a large number of gradual onset injuries involving the distal radius, and distal humerus, and include distal radial growth plate disorders, and, primarily in females, osteochondritis dissecans of the humeral capitellum (loose bodies in the elbow) (Caine et. al., 1996). Both of these problems are severe, and are the result of shear and compressive forces to stressed and immature joints (Singer and Roy, 1984). Shoulder injuries are especially common amongst male gymnasts and are most frequently muscle strains (acute), or shoulder joint impingements (chronic) (Meeusen and Borms, 1992).
Injury Severity/Time Loss: The quantity of time lost in training or competition as a result of injury is influenced by many factors including injury definition, personal motivation, peer pressure, coaching ethos, and the fact that for most injuries, gymnasts are able to keep training on a different apparatus. In research where injury and recovery time are clearly defined and recorded, some useful data are obtained. Caine et. al. (1989), reported that 41% of injuries required less than 8 days of recovery (defined as returning to previous training level), 33% required between 8 and 21 days, and 26% required more than 21 days recovery. In contrast, Lindner and Caine (1990) reported that only 3% of injuries required less than 8 days recovery, 34% between 8 and 21 days, and 67% more than 21 days. This large difference is due to the fact that Caine et. al. were careful to register all injuries including minor strains, whilst the injury definition used by Lindner and Caine was designed to exclude minor injuries. This highlights the need to standardise injury definitions in order to compare different studies within and between sports.
Injury Severity/Catastrophic Injuries: Catastrophic injuries include fatalities and serious injuries such as quadriplegia. In gymnastics, the very few reported case-studies of catastrophic injuries occurred on the trampoline, mini-tramp, and to a lesser extent, the springboard. Most of these injuries occurred whilst performing back or forward somersaults on the trampoline. The case-studies also reported that catastrophic injuries were most often sustained by highly experienced gymnasts (and/or trampolinists), which may indicate these gymnasts are more at risk of catastrophic injuries due to the complexity of the manoeuvres they are performing (Caine et. al., 1996).
Drop-Out and Long-Term Impact of Injuries: It has been reported that injury acts as a potential source of motivation for drop-out in gymnastics (Caine et. al., 1996). Dixon and Fricker (1993) retrospectively examined injuries to 42 male and 74 female elite artistic gymnasts at the Australian Institute of Sport between 1982 and 1991. They reported that 7% of the gymnasts retired from gymnastics due to injuries requiring surgical intervention, including meniscus lesions, a cruciate ligament rupture, and a stress fracture of the foot. In Caine et al's study (1989), 42% of the elite club gymnasts dropped out of gymnastics during the year long study. This difference reflects the fact that retrospective examinations of medical reports (as in the study by Dixon and Fricker) preclude the possibility that a gymnast leaves as a result of numerous chronic injuries.
An investigation into the long term effects of injury by Wadley and Albright (1993) reported that 45% of previously injured gymnasts still were bothered by the injury approximately three years later. Furthermore, 46% of the gymnasts reported that their injury was not fully recovered after three years, but that they were still "capable of strenuous physical activity" (Wadley and Albright, 1993 p.314). These studies tend to suggest that, although injuries to gymnasts may be chronically long term, they are not catastrophic in nature, and nor do they prevent retired gymnasts from leading a physically active existence.
Injury Risk Factors for Gymnastics: Epidemiological risk factors are categorised as being either extrinsic or intrinsic. There are no studies that indicate with any degree of certainty that a particular risk factor causes an injury. This is mostly because injuries very rarely occur as a result of one single risk factor (Caine et. al., 1996). The results of studies attempting to investigate analytical epidemiology should be viewed with caution given the design limitations present in nearly all such studies. In most cases, these studies are able to link a risk factor with injury - but this in no way suggests that the risk factor causes the injury. For example, Steele and White (1986) reported that taller gymnasts are more at risk of injury. This does not suggest that a particular gymnast's height caused an injury, but rather that height may be one of several contributing factors in the occurrence of an injury.
Intrinsic risk factors: Intrinsic risk factors are athlete based characteristics that predispose an individual to injury. These include physical characteristics, motor/functional characteristics, and psychological influences.
Physical characteristics: Biomechanical efficiencies may be gained with particular physiques: decreased height and weight elicit a greater ratio of strength to weight, greater stability and a decreased moment of inertia. Body fat adds to mass without adding to power producing capability therefore fat mass is detrimental to the gymnast. In addition there is an emphasis on leanness for aesthetics by coaches and judges. There may be an increased risk of injury during periods of rapid body growth (Caine, Cochrane, Caine, and Zemper, 1989) due to "increased moments of inertia, increased muscle-tendon tightness, and decreased epiphyseal strength" (Caine et. al., 1996, p.233).
Extrinsic risk factors: Extrinsic risk factors are those that impact on an athlete externally, including exposure (time and event), training methods, environmental conditions (e.g. time of season), and equipment.
Exposure to activity: As gymnasts become more skilled, the amount of time spent training increases (exposure time), and consequently the number of injuries increases. Also, research generally supports an increase in injury rate as competition level increases (Caine, 1989; NCAA, 1994; Mackie and Taunton, 1994; Weiker, 1995). This is possibly because, as gymnasts reach a higher level of competition, they perform more complex (and risky) manoeuvres. Caine et. al. (1989) reported that the most injury prone gymnasts (based on time loss due to injury) were elite level competitors.
Equipment: Improved gymnastics safety equipment, in the form of sprung floors, sprung beams, thicker landing mats and fibre glass rails has offset the expected decrease in injury incidence by enabling the performance of increasingly complicated and risky performance routines (Caine et. al., 1996). The high rate of injury during competition has led to some suggestions of increasing the thickness of landing mats used in competitions. Poorly attended safety equipment is implicated in the occurrence of some injuries such as the numerous reported cases of gymnasts spraining an ankle by landing between badly aligned mats.
Further research is required on the effect of the intensity of activity, the types of equipment and the types of activity (e.g. warm-up and stretching) on injury risk.
The New Zealand Gymnastics Science and Medicine Advisory Committee considered options for the reduction and prevention of gymnastics injury including improved design of training sessions, increased monitoring of gymnastics safety equipment, and comprehensive monitoring of gymnasts by medical professionals. The "New Zealand Elite Gymnastics Injury Study" was developed and aimed to develop a computerised data base of gymnastic injuries and their possible risk factors (training, musculoskeletal, anthropometric, medical and psychological variables); to provide timely and appropriate medical and scientific advice upon identification of injury risk factors or injuries; and to provide educational material on risk factors for gymnastics.
The aim of the screening and prospective study was to investigate the ease of collecting injury, training, and musculoskeletal data with the aim of identifying risk factors for gymnastics injury in a selected cohort of 19 elite gymnasts. Ethics was gained from the University of Auckland ethics committee, and funding was obtained from Sports Science New Zealand. An introductory seminar was run for the gymnasts, their coaches and parents to explain the aims of the study and the possible benefits to the gymnasts. Gymnasts were asked to fill in a sample training and injury form to ensure understanding of what was required for the data collection period. Gymnast demographics, detailed training and competing information, and injury report forms have been collected prospectively for six months. Musculoskeletal, psychological, medical and anthropometric screenings have been conducted every three months. Weekly feedback on training and injury information was given to gymnasts. This paper outlines the preliminary results from the initial screening session, and two months of training & injury data collection.
Gymnastics Population Studied: For practical reasons the number of gymnasts in the study was limited to the 19 New Zealand elite/developmental squad gymnasts (6 male artistic 18.4±3.6 years old; 9 female artistic 14.6±1.2 years old, and 4 rhythmic 17.6±2.1 years old) based in Auckland. The average gymnastics experience at the start of the study for the women artistic gymnasts was 7.7 +/- 1.7 years, for the men was 9.1 +/- 4.3 years and for the rhythmic women was 7.8 +/- 1.0 years.
Training and Competition Information: Training information was collected in an attempt to correlate injury to training factors such as time spent on individual apparatus, or total amount or intensity of training. Competition information was collected to allow a comparison between injury rates in competition and training and the factors associated with gymnastic performance under competition. Gymnastics activity forms were filled in by the gymnasts at the end of each session and were collected weekly.
Injury Data Collection/Injury Definition: The definition of injury was agreed upon by the coaches, gymnasts and researchers at the information seminar and was a compromise between vigorous research definitions and a definition that was practical for data collection in the gymnasium: An injury occurring in gymnastics that requires medical attention OR a gymnastics injury that is an ankle sprain, a knee sprain, a shoulder sprain, or a back sprain/strain that prevents or restricts the gymnast from training or competing in any activity/apparatus in any way and/or for any length of time.
Musculoskeletal Screening: Musculoskeletal screening was conducted by two sports physiotherapists using standard clinical tests (see Table 5). The tests chosen from a bank of possible procedures were those considered to target the anatomical regions that appear to be most clinically affected. Some tests were directed to reveal muscle weakness in core trunk stabilisers and the associated hypermobility of compensating structures, especially the thoraco-lumbar spine and hip joints, i.e. detecting overuse injuries to the lower limb and lower back. Proprioceptive (balance) skills critical to stability, but often impaired post-injury without the athletes/coaches knowledge, were also examined. Muscle balance details were then summarised along with low to high risk areas, to enable medical and coaching management to focus on key issues for each gymnast.
Medical Screening: The objective of the medical screening was to identify any problem areas that would need attention such as low blood iron levels or asthma. Standard medical procedures and tests were conducted by two sports medicine doctors. Blood and urine samples were taken by a clinical laboratory.
Anthropometric Screening: The objective of the anthropometry screening was to provide gymnasts with information on their levels of body fat and muscularity. Bone lengths and widths were also measured so that follow-up sessions could identify whether growth was occurring. Full anthropometry profiles were developed using ISAK criteria (Norton and Olds, 1997) and were conducted by two certified anthropometrists.
All of the gymnasts reported that the activity and injury forms were easy to complete, and only required approximately 2-5 minutes to complete (unless an injury occurred). It is noted that when feedback is provided to the coaches and athletes it usually results in a change in training, nutrition, psychological support etc. in an attempt to improve performance. Given the ethical considerations involved in not giving medical and scientific feedback to the gymnasts when required, the study was designed to be descriptive, i.e. to document the changes in training with the incidence of injury. The study is on-going, hence a summary of the first two months of data is presented.
Screening: Gymnasts had somatotypes consistent with international gymnasts, although three gymnasts were referred to the nutritionist given low sums of skinfolds and one gymnast was also referred given large sums of skinfolds. Medical screening indicated that 32% of the (6/19) gymnasts had asthma but this was under medical control. A variety of medical conditions were present in the gymnasts including low back pain, Servers disease, patellofemoral pain, Osgood-Schlatters disease, elbow dislocation, shoulder subluxation/tendonitis, anterior ankle impingement, and L5/S1 spondylolisthesis.
Musculoskeletal screening (see Table 5) indicated that all gymnasts exhibited lower abdominal strength below the physiotherapists stated required levels for core stability; All gymnasts exhibited patterns of lumbar dysfunction due to muscle imbalance factors; Both artistic groups were tight in their iliotibial band and rectus femoris thigh muscles; The rhythmic gymnasts exhibited hypermobility in both their thoracolumbar spines and hip joints. The range of motion tests showed similar results on both left and right sides. The hip quadrant test also produced some problems in all three groups. The balance test results were poor, which was suprising given that gymnastics requires a high level of balancing ability.
Gymnastics Activity: Time spent on activities within a gymnastics training session was fairly evenly distributed except for men's vault which received less time than the other events. Time was fairly evenly distributed for competition activities except for rhythmic gymnasts who spent a large proportion of the time (44%) in warm-up.
There is limited gymnastics injury information that includes event specific exposure time as the injury rate denominator. Therefore, it is uncertain as to whether the number of injuries on the floor is due to the nature of floor exercises themselves or simply because more time is spent on the floor, or a combination of the two. The current study collects event specific training times and records what apparatus was being used at the time of injury, therefore should lead to a clearer picture regarding any relationship between injury and apparatus.
Perceived intensity of activities was higher in competition than in training for all events except for conditioning. This supports a relationship between intensity and injury risk as the injury rate was generally higher in competition than in training (see Table 6). Overall levels of perceived intensity were moderate. The differences in intensity between competition and training indicate that intensity levels during training should be higher to replicate the competition environment.
Perceived concentration levels were higher in competition than in training, and perceived fatigue was lower in competition than in training, yet the injury rate was higher in competition. Overall levels of concentration were subjectively rated lower than expected by the researchers. This highlights the need for concentration to be improved. The relationship between injury and levels of concentration and fatigue need to be further examined.
Injury Characteristics: Table 6 gives the injury rates for males, females and rhythmic gymnasts in the New Zealand study. The injury competition rates were higher than injury training rates for men's artistic and women's artistic. The injury rates for the New Zealand study are consistent with international injury data for gymnastics. Table 7 shows the injury characteristics for the 19 gymnasts in the two month period. The onset of sudden injuries was 67% for the male artistic gymnasts, 67% for the women artistic gymnasts, and 50% for the rhythmic gymnasts. The percentages of injuries in training were 67% for male artistic gymnasts, 56% for women artistic gymnasts and 100% for the rhythmic gymnasts. Injury localisation was noticeably different for all three groups (see Table 7). Rhythmic gymnasts suffered most injuries to the hip region of the body. Artistic women suffered most of their injuries to the lower extremities (ankle and knee) while artistic men suffered the majority of their injuries to the upper extremity (elbow and wrist).
The estimated time missed due to a physical gymnastics problem was 240 minutes of competition for one artistic female gymnast, 3945 minutes of training for eight artistic female gymnasts, 450 minutes of training for two rhythmic gymnasts, and 570 minutes of training for two artistic male gymnasts.
The following recommendations were based upon the evaluation of the initial two months results by medical, scientific and gymnastics personnel.
The initial aims of the study have been met in that a computerised data base of gymnastic injuries and their possible risk factors has been developed (and continues to be added to), and timely and appropriate medical and scientific advice upon identification of injury risk factors or injuries has been provided. Preliminary results indicate that training and musculoskeletal variables are possible risk factors for gymnastics injury. Statistical regression procedures will be used after 1 year of the study to assess any relationships between the proposed risk factors and injury occurrence and severity.
It is suggested that injury data and training data continue to be collected, that risk factors be assessed and interventions developed to reduce the impact of the risk factors, that the effectiveness of the interventions be evaluated, and that clear and frequent communication with all parties is essential. Although data collection can be somewhat laborious and time consuming, the results do provide coaches and athletes with subjective data to assess the training program and the impact on the gymnasts' musculoskeletal growth and general health.