Could women outrun men in ultramarathon races?

To test a hypothesis that the differences in running performances between men and women narrow with increasing race distance, recent best running speeds (m.s-1) of 28 female ultramarathon runners over racing distances from 5 to 90 km were compared with those of male runners matched for 56 km race time, age and training. These comparisons revealed that the men ran faster than the women over 5 to 42.2 km (P < 0.01-0.05), but not in a 90-km race (2.82 +/- 0.04 vs 2.90 +/- 0.09 m.s-1). Declines in the men's and women's running speeds with increasing race distances were best fitted by Y = 2.9.exp.(-0.01.X) + 1.7 and Y = 2.1.exp.(-0.01.X) + 2.0 equations (r = -0.99). Differences between the exponential declines in the men's and women's running speeds over longer race distances were best fitted by a linear Y = -0.006 (X-66) equation (r = -0.98, P < 0.001). The negative slope and the X-axis intercept of this equation at 66 km supports the hypothesis that women ultramarathon runners have greater fatigue resistance than do equally trained men whose performances are superior up to the marathon distance.

Seasonal variation of suicide in South Africa.

Seasonal trends in South African suicide incidence were investigated with a view to ascertaining whether they are consistent with those in the northern hemisphere regarding: (1) the existence of the expected pattern; (2) this pattern being more pronounced for less urbanized groups; and (3) the presence of a secondary fall peak for youth and females. Log-linear modelling was performed to investigate the effect of month and relevant demographic variables on the suicide counts. The 16,389 nationally registered suicide deaths during 1980-1989 were analysed. The expected pattern, with a peak in the spring (that is, in September/October) or summer and a trough in winter, was present. This pattern was more pronounced for a sub-group that is less urbanized and for another sub-group with a relatively low standard of living. The secondary peak in autumn was not present for youth or females. In the northern hemisphere, this secondary peak has been ascribed to sociodemographic factors associated with the commencement of the academic year and (for females) bioclimatic factors associated with gender-specific biological circannual rhythms. The fact that the academic year commences in summer in South Africa indicates that the present findings are consistent with the former explanation.

Thermal pants may reduce the risk of recurrent hamstring injuries in rugby players.

OBJECTIVE: To determine whether the use of thermal pants might reduce the risk of hamstring injury in rugby players. METHODS: 44 male rugby players from the Cape Province, South Africa, who had previously suffered a hamstring injury were given the choice of wearing thermal warming pants or not, and were then monitored for the development of hamstring injuries during the 1992 season. RESULTS: In the group who wore warmers some of the time, the injury rate was significantly lower when using the warmers (3 injuries/1000 playing hours) than when not (57/1000 playing hours). There was no difference in injury rates between groups who either wore warmers all the time or none of the time, probably because the number who wore the warmers all the time was small (n = 5). Eighteen percent of the injuries recurred at exactly the same site in the muscle and within 12 d of returning to rugby after the initial injury. The incidence of injury was high in the first three weeks of the season and again in the same period after the mid-season break. More than 80% of all match and practice time lost by these players during the study was a direct result of their hamstring injuries. CONCLUSIONS: Thermal pants may have a role in preventing recurrent hamstring injuries but other factors such as inadequate preseason training and incomplete rehabilitation after injury are likely to be more significant risk factors for injury.

Optimum experimental designs for properties of a compartmental model.

Three properties of interest in bioavailability studies using compartmental models are the area under the concentration curve, the maximum concentration, and the time to maximum concentration. Methods are described for finding designs that minimize the variance of the estimates of these quantities in such a model. These methods use prior information. Both prior estimates and prior distributions are used. The designs for an open one-compartment model are compared with the corresponding D theta-optimum design for all parameters and also with designs that minimize the sum of the scaled variances of the individual properties.

Androgenic anabolic steroid use in matric pupils. A survey of prevalence of use in the western Cape.

A survey was undertaken to determine the prevalence of use of androgenic anabolic steroids (AAS) by matric pupils in the western Cape. A cluster sample, stratified by language and a subjective assessment of sporting status, of 13 schools in the area was selected, and 1,361 pupils completed a questionnaire containing questions about sports participation and the use of AAS. The prevalence of use of AAS in the sample was 5.9/1,000 and prevalences in subgroups were 11.7/1,000 for males, 12.5/1,000 for male sports participants and 25.4/1,000 for Afrikaans-speaking male sports participants. A significant amount of under-reporting (AAS users denying their status as such) occurred. General knowledge about AAS was poor, particularly among females and non-sports participants. AAS users experienced more pressure to perform well at sport than did non-users; the drugs were obtained mostly from peers and no user indicated that they were legally obtained. Because there is much evidence regarding the detrimental effects of AAS on health, it is clear that a strategy must be adopted to decrease the prevalence of their use in the schoolgoing population.

Clustering of fungal allergen-specific IgE antibody responses in allergic subjects.

Statistical analysis of specific IgE immune responses to a panel of nine allergens from 2,094 patients demonstrated significant clustering between Aspergillus fumigatus, Alternaria alternata, and Cladosporium herbarum, not explained by crossreactive elements. This may represent a linked, high responder status to these fungal antigens in the allergic population.

Accuracy and reproducibility of cholesterol assay in the western Cape.

The accuracy and precision of cholesterol assay in the western Cape region is reported. The survey was carried out over 15 weeks utilising three human EDTA plasma pools with normal, borderline high and high cholesterol levels respectively. All 11 laboratories in the region providing a service to academic, provincial or military hospitals or to the private medical sector were included in the study. Ten of the 11 laboratories utilised automated enzymatic methods of cholesterol assay whereas 1 used a manual procedure based on the Liebermann-Burchard reaction. Methods were standardised by means of a variety of commercial calibrator material in all except 1 laboratory which used reference sera from the Centers for Disease Control, Atlanta. The performance of the 4 best laboratories met the standard of precision recommended for cholesterol assay, viz. total coefficient of variation of less than or equal to 2.5%. However, only 2 of the 11 laboratories achieved the optimum objective of an overall bias of less than 2.0% together with precision of less than or equal to 2.5%. Rational use of cholesterol assay for diagnosis and management will therefore require standardisation of cholesterol assay on a common reference material and greater attention to analytical factors influencing the reproducibility of results. Intrinsic biological variation also contributes uncertainty to the interpretation of a single value. Thus important clinical decisions must be based on two or more assays carried out using appropriate methodology.

Behavioural screening of 10- and 13-year-old pupils in selected schools in the Cape Peninsula.

The outcome of the behavioural screening of 10- and 13-year-old pupils in selected schools in the Cape Peninsula is reported and the implications discussed. According to parents' reports 21% of 10-year-old and 17.6% of 13-year-old children met the criteria for behaviour disorder. The rates according to teachers' reports were 9.5% and 10.5% respectively. Behaviour disorder occurred with significantly greater frequency among boys, pupils older than the expected age for their standard, pupils with an intelligence quotient below 100, and pupils who had a learning disability.