Determinations of performance and mechanical efficiency in nordic skiing.

Determinants of performance and mechanical efficiency of effort have been made on a group of ten male nordic skiers, all participants in the University of Toronto ski-team. The oxygen intake at the maximum attainable speed of skiing on a level course averaged 89.6 percent of the maximum oxygen intake observed during uphill treadmill running; the latter (average 63.9 ml.kg-1 min-1) may be compared with values greater than 80 ml.kg1 min-1 for international competitors. Maximum heart rates and respiratory gas exchange ratios were generally lower during skiing than running, and it is suggested that the maximum oxygen intake attained during skiing is limited by the individual's skill. In support of this the more experienced skiers were able to reach close to 100 percent of the treadmill maximum oxygen intake during level skiing. A multiple regression analysis indicated that the skiing speed sustained over a one-hour period was related to experience of skiing, maximum oxygen intake, and the percentage of body fat. Assuming a dynamic friction coefficient of 0.075, a drag area of 0.7 m2 and a drag coefficient of 1.0, the gross mechanical efficiency of the university-class skier averaged a little under 20 percent, with a net efficiency of 21.3 percent.     

Point-of-care testing of HbA1c and blood glucose in a remote Aboriginal Australian community

OBJECTIVES: To assess the accuracy of point-of-care (POC) measurements of capillary blood glucose and glycosylated haemoglobin (HbA(1c)) levels in a remote Aboriginal community with high diabetes prevalence. DESIGN: Cross-sectional study comparing POC capillary glucose and HbA(1c) results with those from corresponding venous samples measured in a reference laboratory. PARTICIPANTS AND SETTING: 152 residents aged 11-76 years (representing 76% of population aged over 11 years) had POC glucose measurement in November 2003; 88 with POC glucose level > or = 5.0 mmol/L, or self-reported diabetes, had POC HbA(1c) and laboratory glucose and HbA(1c) measurements. MAIN OUTCOME MEASURES: POC fasting capillary levels of glucose (HemoCue Glucose 201 analyser, Medipac Scientific, Sydney) and HbA(1c) (DCA 2000+ analyser, Bayer Australia, Melbourne); correlation and mean difference between capillary POC and venous blood laboratory measurements of glucose and HbA(1c). RESULTS: Mean and median POC capillary glucose levels were 7.99 mmol/L and 6.25 mmol/L, respectively, while mean and median laboratory venous plasma glucose concentrations were 7.63 mmol/L and 5.35 mmol/L. Values for POC capillary HbA(1c) and laboratory HbA(1c) were identical: mean, 7.06%; and median, 6.0%. The correlation coefficient r for POC and laboratory results was 0.98 for glucose and 0.99 for HbA(1c). The mean difference in results was 0.36 mmol/L for glucose (95% CI, 0.13-0.62; limits of agreement [LOA], - 2.07 to 2.79 mmol/L; P = 0.007) and < 0.01% for HbA(1c) (95% CI, - 0.07% to 0.07%; LOA, - 0.66% to 0.66%; P = 0.95), respectively. CONCLUSIONS: POC capillary HbA(1c) testing, in particular, offers an accurate, practical, community-friendly way of monitoring diabetes in rural and remote clinical settings. POC capillary glucose results should be confirmed by a laboratory test of venous plasma if the results are likely to significantly influence clinical decisions.