Liesl Grobler

Skeletal muscle pathology in endurance athletes with acquired training intolerance

Background: It is well established that prolonged, exhaustive endurance exercise is capable of inducing skeletal muscle damage and temporary impairment of muscle function. Although skeletal muscle has a remarkable capacity for repair and adaptation, this may be limited, ultimately resulting in an accumulation of chronic skeletal muscle pathology. Case studies have alluded to an association between long term, high volume endurance training and racing, acquired training intolerance, and chronic skeletal muscle pathology. Objective: To systematically compare the skeletal muscle structural and ultrastructural status of endurance athletes with acquired training intolerance (ATI group) with asymptomatic endurance athletes matched for age and years of endurance training (CON group). Methods: Histological and electron microscopic analyses were carried out on a biopsy sample of the vastus lateralis from 18 ATI and 17 CON endurance athletes. The presence of structural and ultrastructural disruptions was compared between the two groups of athletes. Results: Significantly more athletes in the ATI group than in the CON group presented with fibre size variation (15 v 6; p  =  0.006), internal nuclei (9 v 2; p  =  0.03), and z disc streaming (6 v 0; p  =  0.02). Conclusions: There is an association between increased skeletal muscle disruptions and acquired training intolerance in endurance athletes. Further studies are required to determine the nature of this association and the possible mechanisms involved.

National and multinational prospective trial registers

Clinical trials are an essential source of scientifi c evidence on the safety and eff ectiveness of health interventions. Prospectively registering information about a trial before enrolling participants, tracking changes to that information via a publicly accessible audit trail, and reporting results on completion of the trial helps protect against reporting biases and over-optimistic conclusions about treatment benefi ts. Open-access registries should decrease wasteful duplication of research, promote more effi cient allocation of research funds, and ensure trial information is disseminated and incorporated into the appropriate body of evidence for clinical, funding, and ethical decision-making. The increased commitment to prospective trial registration and the establishment of trial registers has the potential to increase the number of duplicate registrations (panel). It has been argued that if duplicate trial registration is left unchecked, the integrity of trial registries may be compromised, which would falsely over-infl ate the number of trials and confuse users. Limiting the number of registries has been proposed as a possible mechanism to prevent duplicate trial registration. Despite these concerns, there are several compelling reasons why both national and multinational registers are important. National registers are ideally placed to promote, identify, and track clinical trials in a specifi c country. Such registers can fully integrate into local ethics and regulatory processes, which thus ensures complete and comprehensive registration of all trials in their region of infl uence. Such decentralised trial registration is essential to achieve a comprehensive global register of all clinical trials. A philosophical reason underpinning the need for national registers is that most national registers have been developed within specifi c political frameworks and policy makers value them as a source of national pride. It may therefore not be politically expedient to dismiss these registers or undermine their legitimacy. Multinational registers can be especially important in resource-poor settings where individual countries do not have the necessary resources to establish national registers. Such registers serve the needs of several neighbouring countries, usually with similar disease burdens. By sharing technical and operational resources, costs to individual countries can be reduced and promotion of registration can be streamlined across countries (eg, by working with established regulatory or inter-government organ isations, such as WHO/AFRO in Africa or the Pan American Health Organisation in Latin America). There is an urgent need, particularly in resource-poor countries, to improve the ability of researchers to do high-quality clinical trials. National and multi national registers are able to identify and meet the needs of these researchers, by ensuring that information on various aspects of study design is collected and checked on registration. At an operational level, national and multinational registers can customise the registration process to suit the needs of their particular users (eg, displaying information in the local language). It is essential that WHO’s International Clinical Trial Registry Platform continues to work closely with governments and multinational bodies that have the necessary

Comparative effects of zopiclone and loprazolam on psychomotor and physical performance in active individuals.

ObjectiveSedative hypnotics are used by athletes to alleviate precompetition anxiety and insomnia. The effects of these agents on exercise tolerance have not been extensively researched. DesignTo determine the effects of sedative hypnotics on psychomotor and physical performance, a double-blind, placebo- (P) controlled, cross-over designed trial investigated the effects of zopiclone (Z) and loprazolam (L) on performance in 12 athletes. InterventionSubjects ingested either P, Z (7.5 mg), or L (2 mg) on three different occasions separated by a 1-week washout period. Eye–hand coordination tests, a 30-m sprint test, an agility test, and a graded treadmill run to exhaustion for determination of VO2max were performed 10 hours after drug administration. ResultsSubjects reported a significantly greater hangover effect following ingestion of L (8/11 subjects) compared with ingestion of Z (3/11 subjects; p < 0.01). A greater number of subjects felt alert after ingestion of P (9/11 subjects) and Z (9/11 subjects) compared with L (4/11 subjects; p < 0.01). The results of the eye–hand coordination tests, the 30-m sprint, the T-test, the VO2max, and the time to exhaustion during the treadmill run were not significantly altered following the ingestion of P, Z, and L. There was a significant difference between the delta values for Z and L for the number of missed responses in the eye–hand coordination tests (p < 0.02). Therefore, following the ingestion of L, subjects experienced a significant hangover effect and altered reaction time, whereas the ingestion of Z did not significantly impair either psychomotor or physical performance in the administered tests. Clinical RelevanceInvestigate the extent of the effects of sedative hypnotics on exercise performances, enabling team physicians to prescribe such drugs to the athlete more effectively.

The epidemiology of tuberculosis in health care workers in South Africa: a systematic review

BackgroundIn South Africa, workplace acquired tuberculosis (TB) is a significant occupational problem among health care workers. In order to manage the problem effectively it is important to know the burden of TB in health care workers. This systematic review describes the epidemiology of TB in South African health care workers.MethodsA comprehensive search of electronic databases [MEDLINE, EMBASE, Web of Science (Social Sciences Citation Index/Science Citation Index), Cochrane Library (including CENTRAL register of Controlled Trials), CINAHL and WHO International Clinical Trials Registry Platform (ICTRP)] was conducted up to April 2015 for studies reporting on any aspect of TB epidemiology in health care workers in South Africa.ResultsOf the 16 studies included in the review, ten studies reported on incidence of active TB disease in health care workers, two report on the prevalence of active TB disease, two report on the incidence of latent TB infection, three report on the prevalence of latent TB infection and four studies report on the number of TB cases in health care workers in various health care facilities in South Africa. Five studies provide information on risk factors for TB in health care workers. All of the included studies were conducted in publicly funded health care facilities; predominately located in KwaZulu-Natal and Western Cape provinces. The majority of the studies reflect a higher incidence and prevalence of active TB disease in health care workers, including drug-resistant TB, compared to the surrounding community or general population.ConclusionsThere is relatively little research on the epidemiology of TB in health care workers in South Africa, despite the importance of the issue. To determine the true extent of the TB epidemic in health care workers, regular screening for TB disease should be conducted on all health care workers in all health care facilities, but future research is required to investigate the optimal approach to TB screening in health care workers in South Africa. The evidence base shows a high burden of both active and latent TB in health care workers in South Africa necessitating an urgent need to improve existing TB infection, prevention and control measures in South African health care facilities.

Evaluation of maximal exercise performance, fatigue, and depression in athletes with acquired chronic training intolerance.

Objective:This study compared differences in maximal strength and aerobic capacity and symptoms of fatigue and depression in athletes with acquired training intolerance (ATI) and control athletes (CON) matched for age and current training volume who did not have symptoms of excessive or chronic fatigue associated with their sporting activity. Setting:University of Cape Town, Sports Science Institute of South Africa. Participants:Twenty ATI and 10 CON athletes participated in the trial. Although the ATI athletes reported symptoms of excessive fatigue during exercise, or symptoms of fatigue that occurred at rest and during activities of daily living, they did not fulfill the criteria for a diagnosis of chronic fatigue syndrome. Main Outcome Measures:A training and comprehensive medical history was recorded from all subjects. The Beck Depression Inventory Short Form (BDI-SF) was used to assess levels of depression in both ATI and control subjects. Maximal force output during a 5-second isometric voluntary knee extensor muscle contraction, and maximal aerobic capacity (VO2max), maximal heart rate (HRmax), and maximal blood lactate concentrations during a treadmill running test were measured in all subjects. Results:There were no differences in maximal isometric force output, peak treadmill running speed, VO2max, HRmax, or blood lactate concentration at rest or after maximal exercise testing between the ATI and CON athletes. However, the BDI-SF scores were higher in the ATI (7.7 ± 6.6 arbitrary units) than in the CON athletes (1.7 ± 1.5 arbitrary units; (P = 0.0052). Conclusions:These findings suggest that the symptoms of excessive fatigue and acquired training intolerance described by these ATI athletes do not affect their maximal isometric and maximal aerobic capacity, and may be associated with psychologic depression in these athletes.