The energy expenditure and hence energy requirements of 12 young Chinese gymnasts attending a specialized school in Beijing were assessed. Total energy expenditure was measured using the doubly labeled water technique and this, in conjunction with measures of basal metabolic rate (BMR), allows the calculation of a physical activity level (PAL). Mean PAL value for the gymnasts was 1.98, which is significantly different from published mean values found in nongymnast children of a similar age. This mean value is equivalent to very heavy levels of physical activity during the periods of training being undertaken. This is the first time that energy expenditure has been noninvasively measured in free-living young gymnasts. The data will be of use to sports scientists and nutritionists alike.

In infants, sleeping metabolic rate (SMR) is used as a proxy for basal metabolic rate (BMR). BMR can be predicted from anthropometry using published equations. Our study was intended to evaluate the ability of these equations to predict measured SMR in infants aged 6 weeks to 12 months. SMR was measured in a mixed longitudinal study using the Douglas bag technique (n = 105). Measured SMR values were compared with BMR predicted from weight (BMR-1) or weight and length (BMR-2). These equations were not successful in predicting SMR in this age group. Percentage error of predicted BMR was related to infant weight (BMR-1: r = 0.26; p < 0.005; BMR-2: r = 0.18; p < 0.06). Alternative logarithmic equations were derived from this study (R = 0.84-0.87; SEE = 0.159-0.168). We conclude that the new equations, relating to contemporary infants, are more suitable but actual measurements remain preferred.

An investigation was made of long-term variation in oxygen consumption rate (VO₂) in preterm infants. Four subjects (gestational age 27–34 weeks, postnatal age 17–38 days, weight at study 1.1–2.6 kg) were studied for 5 days each using open-circuit, indirect calorimetry. The mean VO₂ for each subject (11.0–11.5 litres/kg/day) was within the reported range. However, the between-subject coefficient of variation during the study (2.1 %) was smaller than the mean between-measurement coefficient of variation for daily VO₂ (3.8%, range 1.7–6.3%). In addition, the between-measurement coefficient of variation was increased further for measurement intervals of less than 24 h (reaching a mean of 8.3% for 1-hour periods), and a relationship between measurement duration and the precision of estimating VO₂ over 3 or 5 days is described. Thus, even 24-hour measurements of VO₂ in these preterm infants were less representative of the individual’s VO₂ over 3 days than the group mean estimate. This finding is of relevance to future studies in this area, particularly those in which short-term measurements of energy expenditure are combined with a nutrient balance study to determine the composition of weight gain, because even small errors in the estimate of total energy expenditure can lead to unacceptably large errors in calculated energy deposition.

In an investigation of the growth patterns of 76 children attending an orthodontic clinic, measurements of standing height were used to study the adolescent growth spurt. Growth curves were fitted to the data by a graphical method, and also by fitting a Preece-Baines model. Both methods produced similar values for age at peak height velocity (PHV), but the graphical method produced higher values for peak velocity. Compared to the results obtained by fitting Preece-Baines curves to a sample from the Harpenden data, the South-east Essex children appear to be attaining significantly higher peak velocities. There was, however, no real difference in the values for age at PHV.