Showing papers in "Occupational Health and Industrial Medicine in 1998"

Harassment in the workplace and the victimization of men

Abstract: Harassment and victimization among male workers were studied in a sample of 460 industrial workers, supervisors and managers within a Norwegian marine engineering industry. The results indicated that aggression and harassment are significant problems in this organizational setting. On a weekly basis, 7% of the men reported being subjected to at least one of the following behaviors from coworkers or supervisors: ridicule and insulting teasing, verbal abuse, rumors and gossips spread about themselves, offending remarks, recurring reminders on blunders, hostility or silence when entering a conversation, or the devaluing of one's effort and work. As many as 22% reported being subjected to one or more of these acts at least monthly. Although such acts and conducts are common and experienced by most organization members now and then, they may significantly impair psychological health and well-being as well as overall job satisfaction when occurring consistently and systematically. Significant correlations were found between exposure to harassment and both job satisfaction and psychological health and well-being. Strong correlations were found between exposure to harassment and dissatisfaction with co-worker interaction.

Flexibility and its effects on sports injury and performance

Abstract: SummaryFlexibility measures can be static [end of ROM (range of motion)], dynamic-passive (stiffness/compliance) or dynamic-active (muscle contracted, stiffness/compliance). Dynamic measures of flexibility are less dependent on patient discomfort and are more objective. Acute and chronic changes in flexibility are likely to occur with stretching exercises, but it is difficult to distinguish between changes in stretch tolerance as opposed to changes in muscle stiffness. How flexibility is measured impacts these findings. There is no scientifically based prescription for flexibility training and no conclusive statements can be made about the relationship of flexibility to athletic injury.The literature reports opposing findings from different samples, frequently does not distinguish between strain, sprain and overuse injury, and rarely uses the proper denominator of exposure.There is basic scientific evidence to suggest that active warm-up may be protective against muscle strain injury but clinical research is equivocal on this point. Typically, specific flexibility patterns are associated with specific sports and even positions within sports. The relationship of flexibility to athletic performance is likely to be sport-dependent. Decreased flexibility has been associated with increased in-line running and walking economy. Increased stiffness may be associated with increased isometric and concentric force generation, and muscle energy storage may be best manifested by closely matching muscle stiffness to the frequency of movement in stretch-shorten type contractions.

Braced for impact: Reducing military paratroopers' ankle sprains using outside-the-boot braces

Abstract: Objective: To determine the presence of chronic traumatic brain injury in professional soccer players. Methods: Fifty-three active professional soccer players from several professional Dutch soccer clubs were compared with a control group of 27 elite noncontact sport athletes. All participants underwent neuropsychological examination. The main outcome measures were neuropsychological tests proven to be sensitive to cognitive changes incurred during contact and collision sports. Results: The professional soccer players exhibited impaired performances in memory, planning, and visuoperceptual processing when compared with control subjects. Among professional soccer players, performance on memory, planning, and visuoperceptual tasks were inversely related to the number of concussions incurred in soccer and the frequency of \"heading\" the ball. Performance on neuropsychological testing also varied according to field position, with forward and defensive players exhibiting more impairment. Conclusion: Participation in professional soccer may affect adversely some aspects of cognitive functioning (i.e., memory, planning, and visuoperceptual processing).

Economics of osteoarthritis: A global perspective

Abstract: Musculoskeletal disorders, of which osteoarthritis (OA) is the most common, incur significant economic, social and psychological costs. Costs of illness have risen over recent decades accounting for up to 1–2.5% of the gross national product for those countries studied so far, including the USA, Canada, the UK, France and Australia. Arthritis has a significant impact on psychosocial and physical function and is known to be the leading cause of disability in later life. There are also significant out-of-pocket costs and loss of earnings due to changes in occupation and roles in domestic duties. Current guidelines for the management of OA of hip and knee include the recommendation of inexpensive but effective interventions. Although the guidelines have not had a specific economic evaluation, cost reductions may be expected. OA is a very common disease and will become an increasing economic burden as the population ages.

Intertester and intratester reliability of a dynamic balance protocol using the Biodex Stability System

Abstract: Evaluating balance can be an important part of the rehabilitation protocol of an athletic injury. One purpose of this study was to determine the intertester and intratester reliability scores of single-leg stability on a platform of gradually decreasing stability using the Biodex Stability System (BSS). The second purpose was to determine intertester and intratester reliability scores of subject foot placement on the BSS. Subjects (N = 19) underwent a familiarization session on Day 1 that included five 30-s balance tests on the BSS. In each of the five tests, platform stability gradually decreased over the 30 s. Subjects were tested without footwear at all times. On the second day, each subject was tested twice by the same investigator and once by a second investigator using the same 30-s test. Investigator tests were counterbalanced to eliminate order effects. Intertester intraclass correlations (ICCs) ranged from .70 to .42 for stability index and from .93 to .54 for foot placement. Intratester ICCs ran...

Relationship between limb movement speed and associated contraction of the trunk muscles

Abstract: Rapid shoulder movement is preceded by contraction of the abdominal muscles to prepare the body for the expected disturbance to postural equilibrium and spinal stability provoked by the reactive forces resulting from the movement. The magnitude of the reactive forces is proportional to the inertia of the limb. The aim of the study was to investigate if changes in the reaction time latency of the abdominal muscles was associated with variation in the magnitude of the reactive forces resulting from variation in limb speed. Fifteen participants performed shoulder flexion at three different speeds (fast, natural and slow). The onset of EMG of the abdominal muscles, erector spinae and anterior deltoid (AD) was recorded using a combination of fine-wire and surface electrodes. Mean and peak velocity was recorded for each limb movement speed for five participants. The onset of transversus abdominis (TrA) EMG preceded the onset of AD in only the fast movement condition. No significant difference in reaction time latency was recorded between the fast and natural speed conditions for all muscles. The reaction time of each of the abdominal muscles relative to AD was significantly delayed with the slow movement compared to the other two speeds. The results indicate that the reaction time latency of the trunk muscles is influenced by limb inertia only with limb movement below a threshold velocity.

Second-impact syndrome

Abstract: Second impact syndrome (SIS) occurs when an athlete who has sustained an initial head injury, most often a concussion, sustains a second head injury before symptoms associated with the first have fully cleared. While most commonly reported in football, the SIS can occur during any sport that can produce head blows. Any athlete still complaining of post-concussion symptoms after a head injury must not be allowed to return to play.

Musculoskeletal complaints in the Netherlands in relation to age, gender and physically demanding work

Abstract: Objectives: This cross-sectional study was performed in order to elucidate the relationship of musculoskeletal complaints with age, gender and physically demanding work in the Netherlands.

Fat metabolism during exercise: A review. Part I: Fatty acid mobilization and muscle metabolism

Abstract: This is the first part in a series of three articles about fat metabolism during exercise. In this part the mobilization of fatty acids and their metabolism will be discussed as well as the possible limiting steps of fat oxidation. It is known for a long time that fatty acids are an important fuel for contracting muscle. After lipolysis, fatty acids from adipose tissue have to be transported through the blood to the muscle. Fatty acids derived from circulating TG may also be used as a fuel but are believed to be less important during exercise. In the muscle the IMTG stores may also provide fatty acids for oxidation after stimulation of hormone sensitive lipase. In the muscle cell, fatty acids will be transported by carrier proteins (FABP), and after activation, fatty acyl CoA have to cross the mitochondrial membrane through the carnitine palmytoyl transferase system, after which the acyl CoA will be degraded to acetyl CoA for oxidation. The two steps that are most likely to limit fat oxidation are fatty acid mobilization from adipose tissue and transport of fatty acids into the mitochondria along with mitochondrial density and the muscles capacity to oxidize fatty acids.

The relationship of running to osteoarthritis of the knee and hip and bone mineral density of the lumbar spine: A 9 year longitudinal study

Abstract: Objective. To determine the associations between running and radiographic hip osteoarthritis (OA), the progression of radiographic knee OA, and changes in bone mineral density (BMD) after 9 year followup in 28 members of a running club now aged 60-77 years and 27 nonrunner controls. Methods. Running subjects and non running controls were matched for age (± 2 years), years of education, and occupation. All subjects underwent rheumatologic examination, completed annual questionnaires, and had radiographs taken of the knees in 1984, 1986, 1989, and 1993 and of the hips in 1993. BMD of the first lumbar spine vertebrae was obtained in 36 subjects by quantitative computed tomography (QCT) in 1984, 1986, 1989. and 1993. In 1993, knee radiographs were assessed in pairs (1984 and 1993), and hip radiographs were scored by 2 readers individually without knowledge of running status. Results. Nine year radiographic results for both runners and nonrunners for the knees showed significant within-group progression of both osteophytes and total knee radiographic scores (p = 0.01 for runners and p = 0.05 for nonrunners) and joint space narrowing in nonrunners (p = 0.01). Runners tended to have higher radiographic scores, but no significant differences in between-group differences were seen in 1984 or 1993. Radiographic OA of the hip was not different between the groups. QCT of the first lumbar vertebrae for BMD in 1984, 1986, 1989, and 1993 was greater in runners than nonrunners (p = 0.01 ), but rates of change in QCT values were similar between the 2 groups (p < 0.001). Conclusion. The presence of radiographic hip OA and the progression of radiographic knee OA was similar for older runners and nonrunners. Lumbar spine BMD remained higher in runners, but changes in lumbar BMD were similar for runners and nonrunners over a 9 year period.

Impact of resistance training on endurance performance. A new form of cross-training?

Abstract: In accordance with the principles of training specificity, resistance and endurance training induce distinct muscular adaptations. Endurance training, for example, decreases the activity of the glycolytic enzymes, but increases intramuscular substrate stores, oxidative enzyme activities, and capillary, as well as mitochondrial, density. In contrast, resistance or strength training reduces mitochondrial density, while marginally impacting capillary density, metabolic enzyme activities and intramuscular substrate stores (except muscle glycogen). The training modalities do induce one common muscular adaptation: they transform type IIb myofibres into IIa myofibres. This transformation is coupled with opposite changes in fibre size (resistance training increases, and endurance training decreases, fibre size), and, in general, myofibre contractile properties. As a result of these distinct muscular adaptations, endurance training facilitates aerobic processes, whereas resistance training increases muscular strength and anaerobic power. Exercise performance data do not fit this paradigm, however, as they indicate that resistance training or the addition of resistance training to an ongoing endurance exercise regimen, including running or cycling, increases both short and long term endurance capacity in sedentary and trained individuals. Resistance training also appears to improve lactate threshold in untrained individuals during cycling. These improvements may be linked to the capacity of resistance training to alter myofibre size and contractile properties, adaptations that may increase muscular force production. In contrast to running and cycling, traditional dry land resistance training or combined swim and resistance training does not appear to enhance swimming performance in untrained individuals or competitive swimmers, despite substantially increasing upper body strength. Combined swim and swim-specific ‘in-water’ resistance training programmes, however, increase a competitive swimmer’s velocity over distances up to 200m. Traditional resistance training may be a valuable adjunct to the exercise programmes followed by endurance runners or cyclists, but not swimmers; these latter athletes need more specific forms of resistance training to realise performance improvement.

Reduction of sick leave for lumbar back and posterior pelvic pain in pregnancy

Abstract: STUDY DESIGN In this prospective, consecutive, controlled cohort study, the authors analyzed the impact of a differentiated, individual-based treatment program on sick leave during pregnancy for women experiencing lumbar back or posterior pelvic pain during pregnancy. OBJECTIVE To identify patients with pain early in pregnancy and, by means of individual information and differentiated physiotherapy, reduce sick leave during pregnancy. SUMMARY OF BACKGROUND DATA Sick leave for back pain during pregnancy is common, and treatment programs have been aimed at reducing pain, for that reason. In Sweden, the average sick leave due to back pain during pregnancy is 7 weeks. METHODS All pregnant women who attended a specific antenatal clinic and experienced lumbar back or posterior pelvic pain were included in an intervention group, and results were compared with women in a control group from another antenatal clinic. RESULTS The intervention group comprised 54 women, compared with 81 women in the control group. Thirty-three women were on sick leave for an average of 30 days in the intervention group versus 45 women for an average of 54 days in the control group (P < 0.001). The reduction in sick leave reduced insurance costs by approximately $53,000 U.S. CONCLUSIONS Sick leave for lumbar back and posterior pelvic pain in the intervention group was significantly reduced with the program, and the program was cost effective.

Fat metabolism during exercise: A review - Part II: Regulation of metabolism and the effects of training

Abstract: This part discusses the complex regulation of fat metabolism. Catecholamines as a stimulator of lipolysis and insulin as a suppressor play very important roles in the regulation of fat oxidation. The interaction of carbohydrate and fat metabolism has been extensively studied in the past decennia but the understanding of this multifactorial regulation is complex and still incompletely understood. In 1963, Randle et al. proposed the glucose-fatty acid cycle as a possible mechanism, and more recently, regulation through malonyl-CoA has been put forward as a possible way to explain shifts in carbohydrate and fat metabolism at rest and during exercise. The exercise intensity affects fat oxidation mainly by increasing lipolysis and fatty acid availability during exercise of low to moderate intensity. At high exercise intensities, both a reduction in fatty acid availability (decreased RaFa) and intramuscular factors reduce fat oxidation. These intramuscular factors are largely unknown. The increased mitochondrial density after training and increased oxidative enzymes may partly explain the increased fatty acid oxidation during exercise as observed after training. However, also supply of fatty acids to the mitochondria may be important. The available evidence suggests that the additional fatty acids oxidized after training are primarily derived from intramuscular triacylglycerols and not from adipose tissue derived fatty acids or circulating triacylglycerols.

Virtual environments and ergonomics: Needs and opportunities

Abstract: Although based on a still immature technology, virtual environments appear to have potential for applications in industry, commerce, medicine and education. The role of ergonomics will be in development of improved virtual environment interfaces and in enabling better utilization of the technology through specifying user needs and requirements and developing evaluation methodologies. By extension, ergonomists will also be involved in building virtual environments for use in areas of ergonomics activity such as workplace layout, interface design, procedures testing, education and training. This paper overviews virtual environment attributes and capabilities and proposes a framework for their specification, development and evaluation, before summarizing current ergonomics research issues. Current work on participant side effects is summarized. A strong case is made for the potential value of ergonomics for virtual environments and vice versa.

Does prolonged high-impact activity contribute to later urinary incontinence? A retrospective cohort study of female olympians

Abstract: Objective To determine whether women engaged in strenuous, provocative exercise are more likely to be incontinent in future life than similarly fit women who participated in less provocative exercise. Methods In this retrospective cohort study, female American Olympians who competed in swimming (low-impact group) and in gymnastics and track and field (high-impact group) between 1960 and 1976 completed a structured questionnaire. Primary outcome measures included the prevalence of the symptoms of stress and urge incontinence. Statistical analyses of results included χ 2 , Fisher exact test, two-tailed t tests, Wilcoxon rank sum test, and stepwise multiple logistic regression. P Results One hundred four women responded (response rate 51.2%). High-impact athletes were older (46.2 compared with 42.4 years) and were more likely to report incontinence when they were doing their sport as Olympians (35.8% compared with 4.5%) than low-impact athletes; low-impact athletes were more likely to be parous (83.3% compared with 60.7%). There was no difference in the prevalence of the symptom of stress incontinence between the highversus low-impact groups: any incontinence, 41.1% compared with 50%; daily or weekly incontinence, 10.7% compared with 8.3%; and incontinence that bothered them moderately or greatly, 10.7% compared with 4.2%. With our sample size, this study had 80% power to detect a fourfold difference in daily or weekly incontinence between groups, but only a 30% power to detect a twofold difference, given a baseline prevalence of 10%. When age, body mass index (BMI), parity, Olympic sport group, and incontinence during Olympic sport were entered into stepwise logistic regression analyses, only BMI was significantly associated with regular stress or urge incontinence symptoms. Conclusion Participation in regular, strenuous, highimpact activity when younger did not predispose women to a markedly higher rate of clinically significant urinary incontinence in later life.

Fat metabolism during exercise: A review. Part III: Effects of nutritional interventions

Abstract: By changes in nutrition it is possible to manipulate fat oxidation. It is often theorized that increasing fat oxidation may reduce glycogen breakdown and thus enhance performance. Therefore, the effects of acute, short-term and long-term fat feeding have been subjects of investigation for many years. Ingestion of long-chain triacylglycerols (LCT) during exercise may reduce the gastric emptying rate and LCT will appear in the plasma only slowly. Medium-chain triacylglycerols (MCT) do not have these disadvantages and they are rapidly oxidized. However, the contribution of MCT to energy expenditure is only small because they can only be ingested in small amounts without causing gastrointestinal distress. So at present, fat supplementation in the hours preceding to or during exercise (either long chain or medium chain triacylglycerols) cannot be recommended. High-fat diets and fasting have been suggested to increase fatty acid availability and spare muscle glycogen resulting in improved performance. Both fasting and short term high-fat diets will decrease muscle glycogen content and reduce fatigue resistance. Chronic high-fat diets may provoke adaptive responses preventing the decremental effects on exercise performance. However, at present, there is little evidence to support this hypothesis. Also from a health perspective, caution should be exercised when recommending high-fat diets to athletes.

The benefits of exercise in individuals with traumatic brain injury: A retrospective study

Abstract: Objective:This study examined the benefits of exercise Design:A retrospective study Setting:A community- based sample Participants:A sample of 240 individuals with traumatic brain injury (TBI) (64 exercisers and 176 nonexercisers) and 139 individuals without a disability (66 exercisers and 73 nonexercisers) Main Outcome Measures:Scales measuring disability and handicap. Results: It was found that the TBI exercisers were less depressed than nonexercising individuals with TBI, TBI exercisers reported fewer symptoms, and their self-reported health status was better than the nonexercising individuals with TBI. There were no differences between the two groups of individuals with TBI on measures of disability and handicap Conclusions:The findings suggest that exercise improves mood and aspects of health status but does affect aspects of disability and handicap

Claim rates of compensable back injuries by age, gender, occupation, and industry: Do they relate to return-to-work experience?

Abstract: Study Design. A retrospective cohort study of Michigan workers' compensation cases involving back injuries in 1986 and 1987 with incidence and outcome data. Objective. To determine claim rates by age, gender, and industry or occupation for compensable back injuries and to investigate the relation between occupation and return to work. Summary of Background Data. The cohort of 24,094 Michigan workers' compensation cases from 1986 and 1987 in which claimants were compensated for back injuries was reviewed. Compensation eligibility requires more than 7 days' disability after injury. Methods. Claim rates for back injuries by age, gender, and industry or occupation using employment data interpolated from 1980 and 1990 Census 1% Public Use Microdata Samples. Cox proportional hazards analysis was performed for return to work in the first 8 weeks after injury, with occupation coded at the three‐digit level. Results. All‐age claim rates for Michigan compensable back injuries by occupation ranged between 0.03% and 1.7% annually (0.39% for all cases) and were generally higher in women in white collar occupations and in men in blue collar occupations. The claim rate peaked in men in the 25‐34 year range, with the highest rates in manual labor occupations. The peak claim rates by age were less marked in women, tending to occur broadly throughout the 25‐44‐year range. Similar all‐age values were recorded by industry. The male‐to‐female risk ratio over all occupations does not vary by age and is approximately 1.4:1. As the classification of occupation became more detailed, large differences in risk were documented within major occupation groups. The highest risk in this study was approximately 6% annually for 25‐44 year old men in driver‐sales (beverage truck drivers and delivery workers). Only 7 of 40 occupation categories showed a significant relative hazard for return to work in the first 8 weeks after injury, and these were blue collar occupations with earlier return than the reference sales category. For Michigan compensable back injuries, a rough estimate of the true annual incidence of new claims is 94% of the reported claim rate. Conclusions. The relative risk of compensable back injury is generally higher for females in white collar occupations, higher for males in blue collar occupations and approximately equal in service occupations. Although the risk of back injury is related to occupation, the same occupational factors do not operate as a barrier to return to work.

Determinants of oxygen uptake: Implications for exercise testing

Abstract: For exercise modalities such as cycling which recruit a substantial muscle mass, muscle oxygen uptake (VO2) is the primary determinant of pulmonary VO2. Indeed, the kinetic complexities of pulmonary VO2 associated with exercise onset and the non-steady states of heavy (>lactate threshold) and severe [>asymptote of power-time relationship for high intensity exercise (Ẇ)] exercise reproduce with close temporal and quantitative fidelity those occurring across the exercising muscles. For moderate (

Implications of potential cure in acute myelogenous leukemia: Development of subsequent cancer and return to work

Abstract: Chemotherapy produces extended remissions, and potential cures, in a small minority of patients with acute myeloid leukemia (AML). We explored whether potentially cured patients were at increased risk of subsequent invasive cancer and were able to return to work. Potentially cured patients were defined as those in first or second complete remission (CR) for at least 3 years based on hazard rates for recurrence or death in CR, which declined sharply after this time. Patients who received allogeneic marrow transplant were excluded. We used questionnaires, phone contact, and chart review to obtain information about subsequent cancer and work status. The number of patients who developed invasive cancer was compared with the number expected based on age, gender, and years of follow-up using the Connecticut Tumor Registry. A total of 215 patients met our criteria for potential cure: 203 in first CR and 12 in second CR (of 1,663 treated between 1965 and December, 1992). At a median of 9.2 years from first or second CR, 163 (76%) remain alive in CR. Fifteen patients developed 18 invasive cancers (expected number of patients, 8.8; observed/expected, 1.70; 95% CI, 0.96 to 2.84; P = . 06). Patients initially treated between 1973 to 1979, patients above the potentially cured cohort's median age of 40 years, and those who presented with abnormalities of chromosomes 5 and/or 7 were more likely to develop subsequent cancer, whereas the observed/expected ratio for younger patients was 1.05 (95% CI, 0.13 to 3.80; P = .56). Seventy-four percent of the patients who were working full-time and who were under age 50 at time of treatment for AML have been working full-time in the last 6 months. Only 17 of 56 patients who are currently not working cited physical limitation as the reason. Patients with potentially cured AML are likely to be able to return to work, and at least if younger do not, on average, have an increased risk of invasive cancer.

Mouse versus keyboard use: A comparison of shoulder muscle load

Abstract: Use of the computer mouse as an input device at visual display units is increasing, yet few studies could be found that directly addressed related musculoskeletal problems. Tasks similar to mousing, such as keyboarding, have been shown to result in static muscle loading of the shoulder, therefore the potential may also exist for increased neck and upper limb disorder with mouse use. The major aim of this pilot study was to compare the dominant shoulder muscle load from upper trapezius and anterior deltoid, gross postures and discomfort during mousing and keyboarding. This was performed in an effort to investigate whether use of the computer mouse is likely to be a risk factor for neck and upper limb disorders and the extent of this risk compared to keyboarding. Eight subjects performed a 10 min computer task with both mouse and keyboard input. Electromyographs of anterior deltoid and upper trapezius muscles, observations of posture and ratings of discomfort were collected. Group differences suggested increased anterior deltoid loads with mouse use and decreased trapezius loads. Also evident was the considerable inter-individual variation in muscle loads. This may help explain the pattern of work-related neck and upper limb disorders. Relevance to industry Investigation of shoulder muscle loading during mousing may help identify risk factors contributing to the development of potentially associated neck and upper limb disorders. Costly negative effects of these disorders to industry can include workers compensation claims, decreased productivity and reduced user satisfaction and well being. Once possible risk factors such as shoulder load are identified, approaches to their minimisation in industry may then be addressed.

Relationship between scores on anger measures and PTSD symptomatology, employment, and compensation-seeking status in combat veterans

Abstract: The interrelationship between the theoretically related constructs of anger and posttraumatic stress disorder (PTSD) symptoms was examined in a group of 42 combat veterans with PTSD using a multimeasure assessment strategy. Scores on several anger measures were found to be quite high in this sample and were significantly correlated with PTSD symptomatology. Furthermore, anger measures were found to be related to employment status independent of PTSD severity, but were not related to disability compensation-seeking status. Clinicians are advised to be aware of the potential implications for physical health and interpersonal functioning, and to incorporate anger management strategies into treatment plans for this population.

Altitude and hypoxia training - A short review

Abstract: The importance of oxygen transport and consumption in the body for endurance performance is the reason why altitude training as preparation for competitions at sea level has become popular. In hypoxia maximal O2 uptake decreases. Thus for equal work load training at altitude is harder and stimulates adaptation processes more than sea level training. A specific altitude training effect, however, can only be proven if a relative equal load (in % of VO2max) is more effective than during sea level training. In only three of 10 investigations with this design has a significant improvement of either maximal performance, VO2max or endurance been found, in two there was a nonsignificant tendency. When training in hypoxia combined with living in normoxia was investigated two of four groups improved. Living in hypoxia with training in normoxia is probably more effective but only preliminary publications are available. Summarizing, a small specific altitude effect on performance capacity seems to exist, which may be counteracted by negative influences like reduced stimulation of muscular metabolism. A series of single physiological changes at altitude might have positive or negative implications on training success: training of respiratory muscles, increase of hypoxic ventilatory stimulation, reduced heart training by vegetative "braking", increase of red cell and plasma volume (the latter after descent), right shift of the oxygen dissociation curve, increase of oxidative muscle enzymes (only after hypoxia training), shift from fat and muscle glycogen to blood glucose combustion, reduced lactic acid and ammonia production, increase in buffer capacity.

The epidemiology of sports-related traumatic brain injuries in the United States: Recent developments

Abstract: We examined recent population-based data from the National Health Interview Survey, Consumer Product Safety Commission, and state-based traumatic brain injury (TBI) surveillance programs that provide estimates of the overall incidence of sports-related TBI in the United States. Available data indicate that sports-related TBI is an important public health problem because of the large number of people who incur these injuries each year (approximately 300,000), the generally young age of patients at the time of injury (with possible long-term disability), and the potential cumulative effects of repeated injuries. The importance of this problem indicates the need for more effective prevention measures. The public health approach can guide efforts in injury prevention and control. The steps in this approach are (1) identifying the problem, (2) identifying risk factors, (3) developing and testing interventions, and (4) implementing programs and evaluating outcomes. Each of these steps requires adequate data. This article examines the limitations of current sports-related TBI data and suggests ways to improve data in order to develop more effective injury prevention strategies. The impact of sports-related TBI on the public indicates that this task deserves a high priority.

Thirst at work - an occupational hazard?

Abstract: Of 1492 teachers 791 (53%) responded to a survey addressing whether voiding habits at work or behavioral factors influenced by this occupation predisposed women to urinary tract infection. The mean number of voids during the work day was 2.7±1.4; 24.5% voided infrequently (never or only once) and 26.5% voided four or more times during the work day; 15.8% had had a urinary tract infection in the preceding year. Half of the respondents made a conscious effort to drink less while working, to avoid needing to use the toilet. There was no association between the prevalence of urinary tract infection and the number of voids or infrequent voiding at work. Compared to women who drank the volume they desired at work, those who drank less had a 2.21-fold higher risk (95% CI 1.45–3.38) of urinary tract infection after controlling for being parous, voiding infrequently at work, and urge incontinence. Further study is warranted to determine whether modification of behavioral factors at work can reduce the incidence of urinary tract infections. If this association holds, public policy must be changed to allow workers more adequate access to toilet facilities.