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Synchronized swimming is an aesthetic sport comparable to, in terms of its physical demands, those sports that require high metabolic conditioning. This article discusses injuries related to the demanding combination of strength, speed, and flexibility, including shoulder instability, lower back injuries, medial stress syndromes of the knee, and injury management treatment regimens.
A retrospective analysis of 200 patients requiring cervical disc surgery was performed to determine the frequency of coexistent lumbar disc or spine abnormalities. The duration of follow-up ranged from 5 to 25 years, averaging 14 years. Sixty percent were women and 40% were men, their ages ranging from 25-73 years. Antecedent motor vehicle injury had occurred in 49 cases and work injury to the spine in 23. Sixty-four percent had no history of prior back injury. It was found that over 31% had undergone lumbar disc surgery, and a high number of patients demonstrated abnormal lumbar radiographs or myelograms, including 78 with bulging discs, 100 with major root defects, 78 with minor root defects, 8 with spinal stenosis, and 7 with spondylolisthesis. Myelograms were normal in 22 cases. The sites of lumbar abnormalities included L4-5 (110), L5-S1 (90), and multilevel (8). There was a higher incidence of lumbar disc abnormalities associated with multilevel cervical spondylosis. There also was a relationship between residual symptoms and myelographic abnormalities. Two studies in the authors' institution suggest an autoimmune basis for the frequent coexistence of cervical and lumbar disc disease, namely the demonstration of antigenic properties in the nucleus pulposus and high serum immunoglobulins.
The basic principles of biomechanics are introduced and explained as they relate to the field of ergonomics, especially regarding the lumbar spine. The discussion is organized into the following sections: biomechanics--an overview, spinal structures and loading, biomechanical basis for low-back pain, compressive strength of the lumbar spinal column, biomechanical models, intra-abdominal pressure, lifting technique, and practical applications. The conclusion lists nine guidelines for understanding the internal stresses placed on the lower back by lifting and thereby for avoiding low-back injuries in the workplace.
The exercise and smoking habits of low back or leg pain sufferers vs. persons not having low back or leg pain are compared. The type, frequency and length of exercise is determined from a study of 576 low back or leg pain sufferers compared to 50 persons who state they are symptomatic. The same was done for smoking habits. Thirty-three percent of low back or leg pain sufferers smoked as compared to 14% of those without pain. Forty-seven percent of low back or leg pain sufferers as compared to 86% of non-sufferers exercised regularly. The level of physical activity and general exercise have been found to improve strength, mobility and endurance; this might prevent future back injury. Our study is to determine differences in the exercise habits of persons with low back and/or leg pain vs. those who do not have pain, with the intention being to see if pain sufferers exercise less.
The sport of rowing has gained considerable momentum in recent years. It appeals to many age groups and is an endurance activity with no sudden accelerations or ballistic impact forces. It is associated with several injuries that are so typical that they are easily recognized by the enthusiast and in many cases do not require imaging. These include wrist tenosynovitis, intersection syndrome, and rib fracture. Other injuries may be the result of strenuous training programs or faulty rowing technique and include low back injuries and patellar maltracking. The etiology, biomechanics, imaging, and treatment of rowing-related disorders are discussed.
OBJECTIVES: This article examines associations between selected work- and non-work-related factors and the incidence of chronic back problems over the next two years. DATA SOURCE: The data are from the longitudinal household component of the National Population Health Survey, conducted by Statistics Canada. The analysis is based on 3,234 male and 3,129 female respondents who, in 1994/95, were aged 16 or older, employed, rated their health as good, very good or excellent, and reported no diagnosed chronic back problems. ANALYTICAL TECHNIQUES: All analyses were weighted to represent the Canadian population in 1994/95. Unadjusted cross-tabulations and multiple logistic regression were used to examine the associations between respondents' characteristics in 1994/95 and newly diagnosed chronic back problems in 1996/97. MAIN RESULTS: More than 1 million (9%) Canadian workers aged 16 or older developed chronic back problems between 1994/95 and 1996/97. Back injury, chronic stress, depression, and being aged 40 to 49 were significantly associated with subsequent chronic back problems.
1. Back belts are thought to act by decreasing spinal loading, decreasing vertebral compression, and increasing intra-abdominal pressure by limiting twisting and upper body gross motions. 2. They appear to have little effect on most back injury risk factors, but may have a limited effect on improving muscle strength and supporting the back during lifting and twisting activities. 3. The use of back belts as a psychological support requires further investigation. 4. Based on insufficient objective scientific data, NIOSH recommended against back belt use by healthy people.
The purpose of this study was to examine the effects of two different alignments of the pelvis and three different loads on electromyographic (EMG) activity of the erector spinae and oblique abdominal muscles during squat lifting and lowering. Each of 15 healthy subjects lifted and lowered loads with the pelvis aligned both in an anterior tilt and in a posterior tilt. Based on total duration, both the lift and the lower were divided into two equal phases. The EMG activity of each muscle was quantified for each half of both the lift and the lower and was normalized to the total EMG produced by the muscle during a maximal voluntary isometric contraction. The results indicate (1) that the EMG activity of the erector spinae muscles was greater when subjects maintained an anterior tilt than when they maintained a posterior tilt; (2) that the EMG activity of the oblique abdominal muscles was greater in the first half of the lift than in the second half for both lifting styles, although the opposite was true for both lowering styles; and (3) that the EMG activity increased with increasing loads. The results suggest that the greater trunk muscle activity occurring with the anterior tilt position may ensure optimal muscular support for the spine while handling loads, thereby reducing the risk for low back injury.
A random sample including 2342 cases representative of all occupational back injuries in Quebec (1981) was followed up prospectively over three years to assess the recurrence rate of back problems (lumbar, thoracic, and cervical). Each medical and accident report was reviewed to obtain the site of symptoms and occupation. Age, sex, industrial sector, and number of episodes of absence from work were abstracted from the computerised Quebec Compensation Board files. The recurrence rate was 20.0% at one year follow up and 36.3% at three years. A multivariate analysis using a Poisson regression, was performed to model the risk of recurrence over time. Men had a higher chance of recurrence (risk ratio = 1.85, 95% CI = 1.50-2.27) but among recurrent cases, the average total number of episodes was comparable between men and women. Age showed a protective effect on the probability of recurrence (10 years: RR = 0.93, 95% CI = 0.88-0.98) due to the lower recurrence rate in the 45-64 year old group (31.8%). Cervical and lumbar symptoms had identical recurrence profiles whereas thoracic symptoms had a significantly lower recurrence rate. Drivers had the highest recurrence rate (42.1%) and nurses had the highest average number of recurrences (2.03) among recurrent cases. Both occupations had statistically significant excesses after controlling for the other variables.
BACKGROUND: Plasminogen activator inhibitor-1 (PAI-1), an important regulator of fibrinolysis and extracellular matrix turnover, has been implicated in a number of vascular diseases. Studies demonstrating angiotensin II (Ang II) to be a potent stimulator of PAI-1 expression in cultured vascular cells suggests that the renin-angiotensin system may modulate vascular PAI-1 expression. METHODS AND RESULTS: We examined the effects of the ACE inhibitor captopril on PAI-1 expression in control and balloon-injured rat aorta. Northern blot analysis demonstrated that aortic PAI-1 mRNA expression was 7.6-fold elevated 3 hours (P<.05) after balloon injury, back to baseline at 2 days, increased again at 4 days, and by 7 days after balloon injury was 3.2-fold elevated (P<.05) when compared with control. In captopril-treated rats, the induction of PAI-1 expression by balloon injury was significantly suppressed by 44% (P<.05) in the 7 day group but was not altered in the 3-hour group. Captopril also reduced baseline aortic PAI-1 mRNA. In situ hybridization and immunohistochemistry revealed dense PAI-1 staining of 7-day neointima in untreated rats and a dramatic decrease in PAI-1 in neointima of captopril-treated rats. CONCLUSIONS: This report demonstrates that balloon injury results in both a rapid ACE inhibitor-independent induction of aortic PAI-1 expression and a later increase in PAI-1 in the neointima that is significantly suppressed by captopril. This provides the first evidence that the renin-angiotensin system regulates neointimal PAI-1 expression and that ACE inhibitors can reduce PAI-1 in the vessel wall in vivo.
Low back injury is one of the most common conditions in the workplace. The causes are multifactorial and must be sought during the physician's examination. Failure to perform a comprehensive history and physical examination ultimately can lead to treatment failure and injury recurrence. A comprehensive history and physical may help clinicians to differentiate organic and nonorganic causes of low back pain. Different diagnoses need specific rather than generalized treatment programs. Teaching clinicians the nuances of the history and physical examination in a setting with an injured worker is the goal of this article.
Nursing aides (18 women and six men) at one traditional and one modern geriatric ward, and warehouse workers (16 men) at two different types of warehouse departments were studied during occupational work. The vertical load during manual handling was measured using strain gauges built into wooden shoes. The warehouse workers performed four times as many lifts as the nursing aides and transferred five times as great a mass per unit time. Less than 25% of the lifts were carried out with the load evenly distributed on both feet during both the upward lift and lowering. In the warehouses the lifts were short, while the nursing aides were exposed both to lifts of longer duration and to carrying, as well as a greater frequency of unexpected, sudden and high peak load. The heart rate and oxygen uptake values recorded were relatively low, and both groups utilized approximately 25% of their maximum aerobic power. According to official occupational injury statistics, both warehouse workers and nursing aides belong to risk groups with a high frequency of reported back injuries. However, more injuries are reported by nursing aides than by warehouse workers. Greater muscle strength in male workers may partly explain this difference. Qualitative differences in the design of the lifting work, with more lifts of long duration in awkward work postures, more carrying, more exertion of horizontal forces and a greater frequency of unexpected rapid lifts in the nursing aides may also contribute to the differences in risk of injury between these occupational groups. Considerable differences were found between the two hospital wards as regards lifting frequency, force, duration and the proportion of lifts with an even distribution of load on both feet during upward lift. The lifting work was approximately 50% less in the modern ward, which has easily maneuvered electric overhead hoists, spacious premises and better work organization than in the traditional ward, even though the patient handling needs were equivalent. In the warehouse department at which the wares were stored with easy access, the frequency of lifts with an even distribution of load on both feet was approximately 25%, compared to 7% in the other warehouse department. In conclusion, evaluations of occupational lifting work should include a quantitative assessment of the duration and load distribution of lifting, as well as of postures. Workstation design, technical aids and work organization have a profound effect on the lifting work load even in jobs with equal manual handling demands.
OBJECTIVE: To identify injuries and profile the characteristics of injured skiers and snowboarders younger than 18 years of age in Southern Alberta, Canada. DESIGN: Case-series over one year. PARTICIPANTS: Injured skiers and snowboarders younger than 18 years of age presenting to the ski patrol members at each of seven ski areas in Southern Alberta. MAIN OUTCOME MEASURES: Information on injured individuals reporting to the ski patrol at the involved areas was documented on a standardized injury reporting form. Anonymous information was then copied and sent to the University of Calgary Sport Medicine Centre, where the data were analyzed. Proportions of injured skiers and snowboarders with specific characteristics or participating in specific environmental conditions are presented. RESULTS: There were a total of 832 (60.0%) injury reports filed for skiers and 557 (40.1%) for snowboarders, reflecting 1,635 separate injuries. Head injuries were the most frequently reported (19.1% of all regional injuries). The most commonly injured region was the knee among skiers (n = 213; 22.8%) and the wrist among snowboarders (n = 173; 27.8%). Lower extremity injuries in skiers and upper extremity injuries in snowboarders were most common. Younger male skiers and snowboarders reported high proportions of head, neck, and back injuries. CONCLUSION: The lower extremity in skiers and the upper extremity in snowboarders were most susceptible to injury. A cause for concern is the high proportion of head injuries reported for both male skiers and snowboarders of younger age groups. Further study into protective equipment design and function is required.
Low back injuries account for the greatest loss of playing time for professional fast bowlers in cricket. Previous radiological studies have shown a high prevalence of degeneration of the lumbar discs and stress injuries of the pars interarticularis in elite junior fast bowlers. We have examined MRI appearance of the lumbar spines of 36 asymptomatic professional fast bowlers and 17 active control subjects. The fast bowlers had a relatively high prevalence of multi-level degeneration of the lumbar discs and a unique pattern of stress lesions of the pars interarticularis on the non-dominant side. The systems which have been used to classify the MR appearance of the lumbar discs and pars were found to be reliable. However, the relationship between the radiological findings, pain and dysfunction remains unclear.
Several studies have been published on disc degeneration among young athletes in sports with great demands on the back, but few on competitive divers; however, there are no long-term follow-up studies. Twenty elite divers between 10 and 21 years of age, with the highest possible national ranking, were selected at random without knowledge of previous or present back injuries or symptoms for an MRI study of the thoraco-lumbar spine in a 5-year longitudinal study. The occurrence of MRI abnormalities and their correlation with back pain were evaluated. Eighty-nine percent of the divers had a history of back pain and the median age at the first episode of back pain was 15 years. Sixty-five percent of the divers had MRI abnormalities in the thoraco-lumbar spine already at baseline. Only one diver without abnormalities at baseline had developed abnormalities at follow-up. Deterioration of any type of abnormality was found in 9 of 17 (53%) divers. Including all disc levels in all divers, the total number of abnormalities increased by 29% at follow-up, as compared to baseline. The most common abnormalities were reduced disc signal, Schmorl's nodes, and disc height reduction. Since almost all divers had previous or present back pain, a differentiated analysis of the relationship between pain and MRI findings was not possible. However, the high frequency of both back pain and MRI changes suggests a causal relationship. In conclusion, elite divers had high frequency of back pain at young ages and they run a high risk of developing degenerative abnormalities of the thoraco-lumbar spine, probably due to injuries to the spine during the growth spurt.
This article reports the findings of a questionnaire survey of work-injured nurses. Thirty nurses reported back injury caused by lifting and nine causative factors were identified in significantly more than 20 per cent of accidents. The threshold of reported weight at which accidents began to happen was 50.9kg. Nurses were found to be particularly at risk when mobilising patients because walking accidents are not preventable by using non-lifting techniques. The findings suggest that nurses should be equipped with the appropriate levels of expertise in assisting patients with mobilising.
OBJECTIVE: We identified predictive factors of long-term disability in new workers' compensation claims to guide secondary prevention research and target interventions for high-risk claims. METHODS: Workers with 4 or more days of work disability resulting from workplace injuries were followed for approximately 6 years in a population-based retrospective inception cohort study of 81,077 workers. RESULTS: Predictors of long-term disability included delay between injury and first medical treatment, older age, construction industry, logging occupation, longer time from medical treatment to claim filing, back injury, smaller firm size, female gender, higher unemployment rate, and having dependents. We used logistic and quantile regression to investigate predictors of disability. These models produced consistent information regarding predictors. CONCLUSION: These factors can be used to identify jobs or workers at increased risk for long-term disability that warrant prevention intervention.
This study investigated the level of resistance and the level of muscle activation of the prone back exercise. Fifteen male subjects with no previous history of low back injury performed two repetitions of seven exercises. These consisted of four maximal isometric voluntary contractions (MVC) and three prone back extension (PBE) exercises. The subject was lying prone on a table, the upper body was suspended off the end of the table and the legs and thighs were secured to the table with straps. Three starting positions from the horizontal were investigated, 0 degree, 30 degrees and 60 degrees, and were compared with MVC to quantify the level of effort needed to perform the task. The results showed that the three PBE exercises require a level of resistance and a level of muscle activation generally under 40% of the maximum capacity of healthy subjects. Muscle activity of the erector spinae (ES) was slightly greater when the exercise started at 60 degrees, compared to 0 degree and 30 degrees. During the static phase of the PBE exercises, the level of resistance remained at 40% relative to the peak reaction moment of the MVC, but muscular activity of ES tended to work at a lower activity level. In conclusion, since for healthy subjects PBE exercises are low resistance exercises, they seem to be more specifically designed to develop muscular endurance of the back muscles.