Development of peak oxygen uptake from 11-16 years determined using both treadmill and cycle ergometry.

This is the final version. Available from Springer Verlag via the DOI in this record.PURPOSES: To investigate the development of peak oxygen uptake ([Formula: see text]) assessed on both a treadmill and a cycle ergometer in relation with sex and concurrent changes in age, body mass, fat-free mass (FFM), and maturity status and to evaluate currently proposed 'clinical red flags' or health-related cut-points for peak [Formula: see text]. METHODS: Multiplicative multilevel modelling, which enables the effects of variables to be partitioned concurrently within an allometric framework, was used to analyze the peak [Formula: see text]s of 138 (72 boys) students initially aged 11-14 years and tested on three annual occasions. Models were founded on 640 (340 from boys) determinations of peak [Formula: see text], supported by anthropometric measures and maturity status. RESULTS: Mean peak [Formula: see text]s were 11-14% higher on a treadmill. The data did not meet the statistical assumptions underpinning ratio scaling of peak [Formula: see text] with body mass. With body mass appropriately controlled for boys' peak [Formula: see text]s were higher than girls' values and the difference increased with age. The development of peak [Formula: see text] was sex-specific, but within sex models were similar on both ergometers with FFM the dominant anthropometric factor. CONCLUSIONS: Data should not be pooled for analysis but data from either ergometer can be used independently to interpret the development of peak [Formula: see text] in youth. On both ergometers and in both sexes, FFM is the most powerful morphological influence on the development of peak [Formula: see text]. 'Clinical red flags' or health-related cut-points proposed without consideration of exercise mode and founded on peak [Formula: see text] in ratio with body mass are fallacious.Darlington TrustCommunity Fun

Sex-Specific Longitudinal Modeling of Youth Peak Oxygen Uptake.

This is the publisher formatted version. The final version is available from Human Kinetics via the DOI in this record.PURPOSE: To investigate peak oxygen uptake ([Formula: see text]) in relation to sex, age, body mass, fat-free mass (FFM), maturity, and overweight status. METHODS: Multiplicative, allometric models of 10- to 18-year-olds were founded on 1057 determinations of peak [Formula: see text] supported by anthropometry and estimates of maturity status. RESULTS: Baseline models with body mass controlled for showed age to exert a positive effect on peak [Formula: see text], with negative estimates for age2, sex, and a sex-by-age interaction. Sex-specific models showed maturity status to have a positive effect on peak [Formula: see text] in addition to the effects of age and body mass. Introducing skinfold thicknesses to provide, with body mass, a surrogate for FFM explained maturity effects and yielded a significantly (P < .05) better statistical fit in all models compared with those based on FFM estimated from youth-specific skinfold equations. With girls only, the introduction of overweight, defined by body mass index, resulted in a small but significant (P < .05) negative effect, with an age-by-overweight status interaction. CONCLUSIONS: FFM has a powerful influence on peak [Formula: see text] in both sexes. Interpretation of the development of youth aerobic fitness and its application to health should reflect the sex- and maturity-associated variation in FFM.British Heart FoundationCommunity FundDarlington Trus

Interpreting Aerobic Fitness in Youth: The Fallacy of Ratio Scaling.

This is the final version. Available on open access from Human Kinetics via the DOI in this recordIn this paper, we draw on cross-sectional, treadmill-determined, peak oxygen uptake data, collected in our laboratory over a 20-year period, to examine whether traditional per body mass (ratio) scaling appropriately controls for body size differences in youth. From an examination of the work of pioneering scientists and the earliest studies of peak oxygen uptake, we show how ratio scaling appears to have no sound scientific or statistical rationale. Using simple methods based on correlation and regression, we demonstrate that the statistical relationships, which are assumed in ratio scaling, are not met in groups of similar aged young people. We also demonstrate how sample size and composition can influence relationships between body mass and peak oxygen uptake and show that mass exponents derived from log-linear regression effectively remove the effect of body mass. Indiscriminate use of ratio scaling to interpret young people's fitness, to raise "Clinical Red Flags", and to assess clinical populations concerns us greatly, as recommendations and conclusions based upon this method are likely to be spurious. We urge those involved with investigating youth fitness to reconsider how data are routinely scaled for body size.Darlington Trus

Sex-Specific Longitudinal Modeling of Short-Term Power in 11-18 Year-Olds

This is the author accepted manuscript. Available from Lippincott, Williams & Wilkins via the DOI in this record.PURPOSE: To investigate, longitudinally, short-term power output in relation to sex and concurrent changes in age, body mass, fat free mass (FFM), and maturity status. METHODS: Multiplicative multilevel modeling which enables the effects of variables to be partitioned concurrently within an allometric framework was used to analyze the peak power (PP) and mean power (MP) of 388 11-18 year-olds. Multilevel models were founded on 763 (405 from boys; 358 from girls) determinations of PP and MP from Wingate anaerobic tests, supported by anthropometric measures and maturity status. RESULTS: In both sexes, PP and MP were significantly (p<0.001) correlated with age, body mass, and FFM. After controlling for body mass, initial models showed positive effects for age on PP and MP, with negative effects for sex and a sex by age interaction. Sex-specific models showed maturity status to have no additional effect on either PP or MP once age and body mass had been controlled for. Skinfold thicknesses in addition to body mass to provide a surrogate for FFM, yielded a significantly (p<0.05) better statistical fit in all models compared to those based on either body mass or FFM estimated from youth-specific skinfold equations. Models founded on estimated FFM provided a significantly (p<0.05) better fit than those based on body mass. ConclusionsWith body mass controlled for boys' PP and MP are higher than those of girls and sex differences increase with age from 11-18 years. A multilevel modeling approach has showed that in both sexes the most powerful influences on short-term power output are concurrent changes in age and FFM as reflected by the combination of body mass and skinfold thicknesses.Community FundDarlington TrustBritish Heart Foundatio

Recreating the Pulsilogium of Santorio: Outlines for a Historically-Engaged Endeavour

This is the final version of the article. Available on open access from the publisher via the link in this record.Credit: Scientific Instrument SocietyBetween 2015 and 2016 a series of seminars on the history of early modern technology and medicine were held at the Centres for Medical History and Biomedical Modelling and Analysis of the University of Exeter. As a result of that work we laid down the basis for the first historically accurate reconstruction of a seventeenth-century instrument, the pulsilogium of Sanctorius (1561-1636). Previous copies were in fact either simple models for display or lacked any commitment to historical accuracy. This short contribution explores some of the results we obtained from the recreation of this device and experiments we recreated which shed new light on the early application of the pendulum as a scientific instrument. A fuller and much more detailed account of these discoveries will be given in a forthcoming contribution edited by Filip Buyse for a special issue of the Journal of Social and Political Science.The archival research on Santorio’s instruments was originally supported by the SIS Grant awarded in 2014 to Dr Fabrizio Bigotti and has been supported thereafter by the Wellcome Trust as part of a major project on quantification in medicine aimed at classifying, understanding and recreating all of Santorio’s instruments for physiological and physical measurement (106580/Z/14/Z). The reconstruction of Santorio’s Pulsilogium (Type A2), however, is very much a team effort and was part of the engaged research project The Laboratory of Santorio held at the University of Exeter – Centres for Medical History and Biomedical Modelling and Analysis. Finally, we would like to express our gratitude to Prof. Jonathan Barry, Co-director of the Centre for Medical History, for his constant and unconditioned support throughout the project duration

Development of 11- to 16-year-olds' short-term power output determined using both treadmill running and cycle ergometry

This is the final version. Available on open access from Springer via the DOI in this recordPURPOSE: To investigate the development of peak power output (PP) and mean power output (MP) during two different modes of exercise in relation to sex and concurrent changes in age, body mass, fat-free mass (FFM), maturity status and, in the case of MP, peak oxygen uptake ([Formula: see text]). METHODS: PP and MP were determined cycling against a fixed braking force (Wingate anaerobic test) and running on a non-motorized treadmill. Peak [Formula: see text] was determined using cycle ergometry and treadmill running. 135 (63 girls) students initially aged 11-14 years were tested over 2 days on three annual occasions. The data were analysed using multiplicative allometric modelling which enables the effects of variables to be partitioned concurrently within an allometric framework. Multiplicative models were founded on 301 (138 from girls) determinations of PP and MP on each ergometer. RESULTS: With body mass controlled for, both PP and MP increased with age but maturity status did not independently contribute to any of the multiplicative allometric models. Boys' PP and MP were significantly (p < 0.05) higher than girls' values on both ergometers. On both ergometers in both sexes, the most powerful morphological influence on PP and MP was FFM. Ergometer-specific peak [Formula: see text] had a significant (p < 0.05), additional effect in explaining the development of MP. CONCLUSIONS: The development of short-term power output is sex specific but within sex multiplicative allometric models of running- and cycling-determined PP and MP were similar, suggesting that either mode of exercise can be used in future studies of short-term power output in youth.Community FundDarlington Trus

Double or nothing! Clever thinking, double-degree frustration, and returns to Science

Undergraduate double-degrees are ‘a necessary disaster for science’, in the experience of one Science Dean at a major university. Double-degrees bring timetabling and logistics problems, but ‘more so students who have to study for so long then want to leave and work’. This is especially so for degrees with Law. The Dean reported difficulties attracting top students to pursue Honours and Doctorate research. His frustrations were reinforced by heads of science schools across institutions. These interviews were conducted as part of a research series over 2005-2006 exploring issues in academic ways, course structures, teaching and learning at disciplinary interfaces, with a focus on Law:Science double-degrees. Among other findings, academic irritation was matched by frustration among some students with limited opportunity for integration during their double-degree study

Traditional and New Perspectives on Youth Cardiorespiratory Fitness

This is the final version. Available on open access from Lippincott, Williams & Wilkins via the DOI in this recordPurpose This study aimed to review traditional and new perspectives in the interpretation of the development of youth cardiorespiratory fitness (CRF). Methods We analyzed data from (i) the literature which for 80 yr has been traditionally based on interpretations of peak oxygen uptake (V˙O2) in ratio with body mass (BM) and (ii) recent multilevel allometric models founded on 994 (475 from girls) determinations of 10- to 16-yr-olds' peak V˙O2 with measures of age, maturity status, and morphological covariates (BM and fat-free mass), and from 10 to 13 yr, 110 peak V˙O2 determinations of maximum cardiovascular covariates (stroke volume, cardiac output, and arteriovenous oxygen difference). Results The application of ratio scaling of physiological variables requires satisfying specific statistical assumptions that are seldom met. In direct conflict with the ratio-scaled data interpretation of CRF, multilevel allometric modeling shows that with BM controlled, peak V˙O2 increases with age but the effect is smaller in girls than boys. Maturity status exerts a positive effect on peak V˙O2, in addition to those of age and BM. Changes in maximum cardiovascular covariates contribute to explaining the development of CRF, but fat-free mass (as a surrogate for active muscle mass) is the most powerful single influence. With age, maturity status, morphological covariates, and maximum cardiovascular covariates controlled, there remains an unexplained 4% to 9% sex difference in peak V˙O2. Conclusions The traditional interpretation of peak V˙O2 in ratio with BM is fallacious and leads to spurious correlations with other health-related variables. Studies of the development of CRF require analyses of sex-specific, concurrent changes in age- and maturation-driven morphological and maximum cardiovascular covariates. Multilevel allometric modeling provides a rigorous, flexible, and sensitive method of data analysis

The development of aerobic and anaerobic fitness with reference to youth athletes

This is the final version. Available from the publisher via the DOI in this record.Purpose To challenge current conventions in paediatric sport science and use data from recent longitudinal studies to elucidate the development of aerobic and anaerobic ftness, with reference to youth athletes. Methods (1) To critically review the traditional practice of ratio scaling physiological variables with body mass and, (2) to use multiplicative allometric models of longitudinal data, founded on 1053 (550 from boys) determinations of 10–17-yearolds’ peak oxygen uptake (VO2) and 763 (405 from boys) determinations of 11–17-year-olds’ peak power output (PP) and mean power output (MP), to investigate the development of aerobic and anaerobic ftness in youth. Results The statistical assumptions underpinning ratio scaling of physiological variables in youth are seldom met. Multiplicative allometric modelling of longitudinal data has demonstrated that fat free mass (FFM) acting as a surrogate for active muscle mass, is the most powerful morphological infuence on PP, MP, and peak VO2. With FFM appropriately controlled for, age efects remain signifcant but additional, independent efects of maturity status on anaerobic and aerobic ftness are negated. Conclusions Ratio scaling of physiological variables with body mass is fallacious, confounds interpretation of the development of anaerobic and aerobic ftness, and misleads ftness comparisons within and across youth sports. Rigorous evaluation of the development of anaerobic and aerobic ftness in youth requires longitudinal analyses of sex-specifc, concurrent changes in age- and maturation-driven morphological covariates. Age and maturation-driven changes in FFM are essential considerations when evaluating the physiological development of youth athlete

Scientific rigour in the assessment and interpretation of youth cardiopulmo-nary fitness: A response to the paper ‘normative reference values and international comparisons for the 20-metre shuttle run test: Analysis of 69,960 test results among chinese children and youth’

This is the final version. Available from the Journal of Sports Science and Medicine via the link in this recor