The functional fitness capacity of adults with Down syndrome in South Africa.

BACKGROUND: It is well established that there is a relationship between physical inactivity and increased risk for diseases of lifestyle. Persons with Down syndrome (DS) are especially at risk because of physical and health impairments, as well as perceived and real barriers to participation in exercise. The purpose of the study was to establish the functional fitness capacity and predictors of performance of DS adults. METHODS: Data were collected at various intellectual disability centres and private homes in seven provinces of South Africa. Three hundred and seventy-one DS individuals (199 men and 172 women) from 18 to 66 years were tested for balance, flexibility, coordination, muscular strength and endurance, aerobic capacity and functional ability. Data were categorised according to gender and age groups (18-25, 26-35, 36-45, and >45 years). Multiple regression analysis was performed to determine the relationship between the functional task and physical test items. RESULTS: Down syndrome men performed significantly better on all but two tests compared with the women (P < 0.05). DS women performed better on the sit-and-reach flexibility item and the chair stand test; however, differences were not statistically significant from the men. Significant differences across age groups were observed for nine of the 13 functional fitness tests (P < 0.05). Muscular strength items, especially leg strength, significantly predicted functional performance in DS men and women. Aerobic capacity only predicted functional performance in DS men and sit-and-reach flexibility and dynamic balance only in DS women. CONCLUSIONS: Findings of this study provide important information on the functional capacity of DS adults and show which physical attributes contribute to functional performance. Consequently appropriate training programmes can be tailored for this population whom is known to have poor functional fitness.

The effect of backward locomotion training on the body composition and cardiorespiratory fitness of young women.

This study investigated the effect of a backward training program on the physical and fitness condition of young women. Twenty-six healthy female university students (aged 18 - 23 years) took part in three different baseline tests: body composition, a submaximal treadmill test, and a 20-m shuttle run test. Subjects were divided into a training group (n = 13) and a control group (n = 13). The training group completed a six-week backward run/walk training program. The control group was restricted to their daily activities similar to the four weeks prior to the onset of the baseline tests. The training group showed a significant (p = 0.01) decrease in O(2) consumption during both submaximal forward and backward exercise on the treadmill (32 % decrease during backward and 30 % decrease during forward exercise). A significant (p = 0.01) decrease in percentage body fat (2.4 %), a 19.7 % decrease in the sum of skinfolds (p = 0.001) and significantly (p = 0.013) improved predicted VO(2max) values from the forward 20-m shuttle run test (5.2 %) were also found in the case of the training group. The findings suggest that backward walk/run training improves cardiorespiratory fitness for both forward and backward exercise and causes significant changes in body composition in young women.

A computer simulation of free-range exercise in the laboratory.

We present a technique for simulating dynamic field (free-range) exercise, using a novel computer-controlled cycle ergometer. This modified cycle ergometer takes into account the effect of friction and aerodynamic drag forces on a 70-kg cyclist in a racing position. It also affords the ability to select different gear ratios. We have used this technique to simulate a known competition cycle route in Cape Town, South Africa. In an attempt to analyze the input stimulus, in this case the generated power output of each cyclist, eight subjects cycled for 40 min at a self-selected, comfortable pace on the first part of the simulated route. Our results indicate that this exercise input excites the musculocardiorespiratory system over a wide range of power outputs, both in terms of amplitude and frequency. This stimulus profile thereby complies with the fundamental requirement for nonlinear (physiological) systems analysis and identification. Through a computer simulation, we have devised a laboratory exercise protocol that not only is physiologically real but also overcomes the artificiality of most traditional laboratory exercise protocols.

Assessment of a peak flow whistle in nonasthmatic children.

We tested the agreement of peak expiratory flow (PEF) measurements between an electronic spirometer and a peak flow whistle (Whistle Watch, HarMed, Capetown, South Africa). One hundred and three healthy children between ages 6-13 years and with no previous experience in lung function tests participated in the study. Sequential PEF-readings were obtained from the spirometer and the peak flow whistle; all children had an equal number of attempts using both devices. In the case of the spirometer, the highest PEF reading of three acceptable and reproducible efforts was noted as the best PEF (PEF(SPIRO)). Whistle Watch readings were taken as the highest value when the child could activate the whistle. Despite a strong correlation (r = 0.91; R2 = 83%) between the readings of the spirometer and Whistle Watch, there was a lack of agreement between the two devices. For any individual subject, the 95% probability interval ranged between +30.4 to -47 L.min(-1); 64% of the children obtained higher PEF-values on Whistle Watch, compared to the spirometer. These findings suggest that the whistle sound of the peak flow whistle was a significant incentive, which resulted in greater maximal expiratory efforts.

Three-dimensional finite element model of a human mandible incorporating six osseointegrated implants for stress analysis of mandibular cantilever prostheses.

The three-dimensional finite element stress analysis method was used to determine the distribution of stresses in and around a model of six implants which supported a typical fixed complete-arch prosthesis in a simulated human mandible. A load of 100 N was applied at different intervals along the cantilever segment. There was a decrease of stress that reached a minimal level at 15 mm along the cantilever segment. Thereafter, a progressive increase of stresses in the lingual and buccal plates was demonstrated.

[The influence of exercise-induced bronchoconstriction on participation in organized sport]. / Die invloed van oefening-geïnduseerde brongokonstriksie op georganiseerde sportdeelname.

Approximately 70-80% of all asthma sufferers develop acute airway obstruction with exercise, while at least 7% of children in the general population develop exercise-induced bronchoconstriction. The purpose of this study was: (i) to determine whether children in the Cape Peninsula who suffer from asthma and/or exercise-induced bronchoconstriction are as inactive and uninvolved in sport as asthmatic children in the USA; and (ii) whether this uninvolvement is a direct result of their susceptibility to exercise-induced bronchoconstriction. An in-depth study was done on the intensity, frequency and level of participation in sport by children with asthma and/or exercise-induced bronchoconstriction compared with a control group of healthy children without a history of asthma or exercise-induced bronchoconstriction. Children with asthma and/or exercise-induced bronchoconstriction generally maintained a similar level of sport participation as healthy children, and only children with serious asthma or exercise-induced bronchoconstriction experienced limitations with regard to physical activity. It was found that, in contrast to children in the USA, non-participation in sport could not be explained by asthma and/or exercise-induced bronchoconstriction.

The prevalence of exercise-induced bronchoconstriction in Cape Town schoolchildren.

An attempt was made to determine: (i) the prevalence of exercise-induced bronchoconstriction among white and coloured schoolchildren in Cape Town; and (ii) the validity of an exercise test for the diagnosis of asthma in the general population. Children (698 white and 494 coloured) were randomly drawn from schools in the northern suburbs of Cape Town. Each child participated in a standard 6-minute exercise test and spirometric measurements were taken before and 10 minutes after exercise with a portable spirometer. The diagnosis of asthma was based on a questionnaire and personal questioning and included those children who, in the past or at present, suffered episodic or continuous airflow obstruction, which was responsive to a bronchodilator. The criterion for the diagnosis of exercise-induced bronchoconstriction was a 10% decline in forced expiratory volume in 1 second after exercise. The prevalence of exercise-induced bronchoconstriction was significantly higher among white children (5.87%) than coloured children (4.05%). The sensitivity of the exercise test was 0.31 and the specificity 0.97. In contrast to the results of hospital-based studies, the negative predictive value of an exercise test (95%) was found to be greater than the positive predictive value (46%). It is therefore concluded that exercise testing is not a useful screening test for epidemiological use; it is probably useful as a challenge test for detecting asthma in the individual patient when the likelihood of the disease is high.