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Purpose 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.

Background Current evidence of metabolic health benefits of high-intensity interval training (HIIT) are limited to longer training periods or conducted in overweight youth. This study assessed 1) fasting and postprandial insulin and glucose before and after 2 weeks of HIIT in healthy adolescent boys, and 2) the relationship between pre intervention health outcomes and the effects of the HIIT intervention. Methods Seven healthy boys (age:14.3 ± 0.3 y, BMI: 21.6 ± 2.6, 3 participants classified as overweight) completed 6 sessions of HIIT over 2 weeks. Insulin resistance (IR) and blood glucose and insulin responses to a Mixed Meal Tolerance Test (MMTT) were assessed before (PRE), 20 h and 70 h after (POST) the final HIIT session. Results Two weeks of HIIT had no effect on fasting plasma glucose, insulin or IR at 20 h and 70 h POST HIIT, nor insulin and glucose response to MMTT (all P > 0.05). There was a strong negative correlation between PRE training IR and change in IR after HIIT (r = − 0.96, P Conclusion Two weeks of HIIT did not elicit improvements to fasting or postprandial glucose or insulin health outcomes in a group of adolescent boys. However the negative correlation between PRE IR and improvements after HIIT suggest that interventions of this type may be effective in adolescents with raised baseline IR.

Purpose: To investigate peak oxygen uptake (V˙O2) in relation to sex, age, body mass, fat-free mass (FFM), maturity, and overweight status. Methods: Multiplicative, allometric models of 10- to 18-y...

International audience; Purpose :The aims of the present study were to determine during childhood and adolescence (i) the effect of sex on non-oxidative energy production, quantified by the accumulated oxygen deficit (AOD), and (ii) the influence of AOD on high-intensity performance.Methods :Thirty-nine boys and 35 girls aged 10–17 years performed a 60 s all-out test on a rowing ergometer to determine AOD and mean power output (MPO). Multiplicative allometric modelling was used to assess the concurrent effects of lean body mass (LBM) and age on AOD.Results :AOD significantly increased with age in both sexes (p Conclusion :Non-oxidative energy production increased more extensively in boys than girls from the age of 14 years. Age and LBM accounted for the sexual differentiation of AOD during childhood and adolescence. In addition, AOD was found to be a determinant factor of high-intensity performance, more particularly in boys.

International audience; PurposeThe aim of the present study was to investigate (i) how glycolytic metabolism assessed by accumulated oxygen deficit (AODgly) and blood metabolic responses (lactate and pH) resulting from high-intensity exercise change during growth, and (ii) how lean body mass (LBM) influences AODgly and its relationship with blood markers.MethodsThirty-six 11- to 17-year olds performed a 60-s all-out test on a rowing ergometer. Allometric modelling was used to investigate the influence of LBM and LBM + maturity offset (MO) on AODgly and its relationship with the extreme post-exercise blood values of lactate ([La]max) and pH (pHmin) obtained during the recovery period.ResultsAODgly and [La]max increased while pHmin decreased linearly with LBM and MO (r2 = 0.46 to 0.72, p

This study examined the time course of adaptions in insulin sensitivity (IS) in adolescent boys after acute high-intensity interval exercise (HIIE) and moderate-intensity exercise (MIE). Eight boys (15.1±0.4 y) completed three 3-day experimental trials in a randomised order: 1) 8×1 min cycling at 90% peak power with 75 s recovery (HIIE); 2) cycling at 90% of gas exchange threshold for a duration to match work during HIIE (MIE); and 3) rest (CON). Plasma [glucose] and [insulin] were measured before (PRE-Ex), 24 and 48 h post (24 h-POST, 48 h-POST) in a fasted state, and 40 min (POST-Ex) and 24 h (24 h-POST) post in response to an oral glucose tolerance test (OGTT). IS was estimated using the Cederholm (OGTT) and HOMA (fasted) indices. There was no change to HOMA at 24 h or 48 h-POST (all P>0.05). IS from the OGTT was higher POST-EX for HIIE compared to CON (17.4%, P=0.010, ES=1.06), and a non-significant increase in IS after MIE compared to CON (9.0%, P=0.14, ES=0.59). At 24 h-POST, IS was higher following both HIIE and MIE compared to CON (HIIE: P=0.019, 13.2%, ES=0.88; MIE: 9.7%, P=0.024, ES=0.65). In conclusion, improvements to IS after a single bout of HIIE and MIE persist up to 24 h after exercise when assessed by OGTT.

Assessment of plasma insulin and glucose outcomes is important in paediatric studies aimed at reducing future risk of type 2 diabetes and cardiovascular disease. The aims of this study are to determine the between-method agreement and the day-to-day reliability of fasting and oral glucose tolerance test (OGTT)-derived estimates of insulin sensitivity and β-cell function in healthy boys. Fasting and OGTT assesments of insulin resistance and β-cell function were performed on 28 boys (12.3±2.9 years). Measurements were repeated after 1 week (fasting, n=28) and 1 day (OGTT, n=8). Agreement between estimates of insulin resistance and β-cell function was examined using Pearson’s correlation coefficient. Reliability was assessed using change in the mean, Pearson’s correlation coefficient, and typical error expressed as a coefficient of variation (CV). The Matsuda index was positively related with QUICKI (r=0.88, P0.05). For reliability, QUICKI had the lowest CV% for the fasting (4.7%) and the Cederholm index for the OGTT (6.4%) estimates. The largest CV% was observed in fasting insulin (30.8%) and insulinogenic index 30’ (62.5%). This study highlights differences in between-method agreement and day-to-day reliability for estimates of insulin resistance in youth. The low CV supports the use of the FGIR (fasting) and Cederholm (OGTT) indices in this population.

Background: In health-related studies, the development of aerobic fitness in youth is seldom elucidated and often misinterpreted. The issue is confused further by the use of performance data to replace or predict physiological variables. Objectives: To address methodological issues in the determination of young people’s peak oxygen uptake (peak 2); to examine the change in peak 2 with chronological age; to challenge the conventional interpretation of peak 2 in relation to body mass; to investigate the contribution of biological maturation to peak 2; and to clarify young people’s current aerobic fitness in relation to previous generations. Major findings: There is a progressive increase in peak 2 with chronological age in both sexes independent of the influence of body mass. Biological maturation exerts an additional positive effect on peak 2 in both sexes independent of chronological age and body mass. There is no compelling evidence to support a secular decrease in young people’s peak 2 but ubiquitous da...

Three papers which between them raise controversial issues, apply laboratory measures to sport performance, and expose gaps in knowledge were selected for commentary. The first paper (Sports Med. 2016;46:1451–1460) reviews the literature on peak V̇O2 in relation to body size and recommends that peak V̇O2 in youth is best expressed via allometric scaling of lean body mass. The second paper (Pediatr Exerc Sci. 2016;28:456–465) reports that maturity status has no effect on peak V̇O2, respiratory compensation point, or ventilatory threshold in youth soccer players once data have been allometrically normalized by lower limb muscle volume. It concludes that in future this technique should be used to compare the aerobic fitness of youth soccer players. The third paper (Eur J Appl Physiol. 2016;116:1781–1794) demonstrates that V̇O2 kinetics determined in a laboratory is related to measures associated with soccer match play and might distinguish superior performance within a group of highly trained youth players. The commentary stresses the importance of experimental rigor, emphasizes the need for appropriate scaling of physiological variables, challenges spurious correlations with health-related variables, endorses the use of a range of aerobic fitness measures, welcomes the application of laboratory data to sport performance, and identifies areas for future research.

Peak oxygen uptake (V O_2) is internationally recognized as the criterion measure of youth aerobic fitness, but flawed laboratory assessments and fallacious interpretations of peak V O_2 in ratio with body mass have confused our understanding of the development of aerobic fitness. Moreover, the recent emergence of specious predictions of peak V O_2 from performance tests and the promotion of spurious ‘clinical red flags’ and cardiometabolic cut-points have confused our understanding of the relationship between youth aerobic fitness and health. Recent longitudinal studies of 10-18 year-olds using multilevel allometric modelling have empirically demonstrated that peak V O_2 increases in accord with sex-specific, concurrent changes in age- and maturity status-driven morphological covariates with the timing and tempo of changes specific to individuals. During both cycle ergometry and treadmill running age- and maturity-status- driven changes in fat free mass have been revealed as the most powerful morphological influences on the development of youth aerobic fitness. To bring some clarity to current confusion, this paper argues that future studies must be founded on rigorous assessment and interpretation of peak V O_2 and ensure that they address the development of youth aerobic fitness and its relationship with present and future health in relation to appropriate sex-specific morphological covariates governed by individual biological clocks.

NEW FINDINGS What is the central question of this study? Do the phase II parameters of pulmonary oxygen uptake ( VO2 ) kinetics display linear, first-order behaviour in association with alterations in skeletal muscle oxygenation during step cycling of different intensities or when exercise is initiated from an elevated work rate in youths. What is the main finding and its importance? Both linear and non-linear features of phase II VO2 kinetics may be determined by alterations in the dynamic balance between microvascular O2 delivery and utilization in 11-15 year olds. The recruitment of higher-order (i.e. type II) muscle fibres during 'work-to-work' cycling might be responsible for modulating VO2 kinetics with chronological age. ABSTRACT This study investigated in 19 male youths (mean age: 13.6 ± 1.1 years, range: 11.7-15.7 years) the relationship between pulmonary oxygen uptake ( VO2 ) and muscle deoxygenation kinetics during moderate- and very heavy-intensity 'step' cycling initiated from unloaded pedalling (i.e. U → M and U → VH) and moderate to very heavy-intensity step cycling (i.e. M → VH). Pulmonary VO2 was measured breath-by-breath along with the tissue oxygenation index (TOI) of the vastus lateralis using near-infrared spectroscopy. There were no significant differences in the phase II time constant ( τVO2p ) between U → M and U → VH (23 ± 6 vs. 25 ± 7 s; P = 0.36); however, the τVO2p was slower during M → VH (42 ± 16 s) compared to other conditions (P

This commentary highlights 23 noteworthy publications from 2018, selected by leading scientists in pediatric exercise science. These publications have been deemed as significant or exciting in the field as they (a) reveal a new mechanism, (b) highlight a new measurement tool, (c) discuss a new concept or interpretation/application of an existing concept, or (d) describe a new therapeutic approach or clinical tool in youth. In some cases, findings in adults are highlighted, as they may have important implications in youth. The selected publications span the field of pediatric exercise science, specifically focusing on: aerobic exercise and training; neuromuscular physiology, exercise, and training; endocrinology and exercise; resistance training; physical activity and bone strength; growth, maturation, and exercise; physical activity and cognition; childhood obesity, physical activity, and exercise; pulmonary physiology or diseases, exercise, and training; immunology and exercise; cardiovascular physiology and disease; and physical activity, inactivity, and health.

Recent publications in the British Journal of Sports Medicine ( BJSM) (mis)represent and (mis)interpret young people’s cardiorespiratory fitness (CRF) and potentially (mis)inform health promotion and clinical practice. 1 2 The papers recognise peak VO2as the criterion measure of CRF but base their estimations of peak VO2 on performances in 20 m shuttle runs (20mSRT). Moreover, and of serious concern to us, estimated peak VO2 is (mis)represented and (mis)interpreted in ratio with body mass (ie, in mL/kg/min). The papers identify a few of the limitations of shuttle running but a recent meta-analysis succinctly summarised the issues. It demonstrated that with children, over half of correlation coefficients between 20mSRT scores and peak VO2 explain less than 50% of the variance in peak VO2. The meta-analysis reported that the criterion-related validity of the 20mSRT with children was only ‘ moderate ’ and concluded, ‘testers must be aware that the performance score of the 20MSR test is simply estimation and not a direct measure of cardiorespiratory fitness’.3 An example of specious interpretation of 20mSRT scores is the assertion that …

This study aimed to characterize changes in deoxyhemoglobin ([HHb]) response dynamics in boys and girls during ramp incremental exercise to investigate whether the reduced peak oxygen uptake (peak V˙O2) in girls is associated with poorer matching of muscle O2 delivery to muscle O2 utilization, as evidenced by a more rapid increase in [HHb].Fifty-two children (31 boys, 9.9 ± 0.6 yr, 1.38 ± 0.07 m, 31.70 ± 5.78 kg) completed ramp incremental exercise on a cycle ergometer during which pulmonary gas exchange and muscle oxygenation parameters were measured.When muscle [HHb] was expressed against absolute work rate and V˙O2, girls had an earlier change in [HHb], as evidenced by the lower c/d parameter (girls, 54 ± 20 W, vs boys, 67 ± 19 W, P = 0.023; girls, 0.82 ± 0.28 L·min(-1), vs boys, 0.95 ± 0.19 L·min(-1), P = 0.055) and plateau (girls, 85 ± 12 W, vs boys, 99 ± 18 W, P = 0.031; girls, 1.02 ± 0.25 L·min(-1), vs boys, 1.22 ± 0.28 L·min(-1), P = 0.014). However, when expressed against relative work rate or V˙O2, there were no sex differences in ([HHb]) response dynamics (all P0.20). Significant correlations were observed between absolute and fat-free mass normalized peak V˙O2 and the HHb c/d and plateau parameters when expressed against absolute work rate or V˙O2. Furthermore, when entered into a multiple regression model, the [HHb] plateau against absolute V˙O2 contributed 12% of the variance in peak V˙O2 after adjusting for fat-free mass, gas exchange threshold, and body fatness (model R2 = 0.81, P0.001).The sex difference in peak V˙O2 in 9- to 10-yr-old children is, in part, related to sex-specific changes in muscle O2 extraction dynamics during incremental exercise.

Purpose To examine the influence of exercise intensity on postprandial health outcomes in adolescents when exercise is accumulated throughout the day. Methods 19 adolescents (9 male, 13.7 ± 0.4 years old) completed three 1-day trials in a randomised order: (1) rest (CON); or four bouts of (2) 2 × 1 min cycling at 90% peak power with 75 s recovery (high-intensity interval exercise; HIIE); or (3) cycling at 90% of the gas exchange threshold (moderate-intensity exercise; MIE), which was work-matched to HIIE. Each bout was separated by 2 hours. Participants consumed a high fat milkshake for breakfast and lunch. Postprandial triacylglycerol (TAG), glucose, systolic blood pressure (SBP) and fat oxidation were assessed throughout the day. Results There was no effect of trial on total area under the curve (TAUC) for TAG ( P = 0.87). TAUC-glucose was lower in HIIE compared to CON ( P = 0.03, ES = 0.42) and MIE ( P = 0.04, ES = 0.41), with no difference between MIE and CON ( P = 0.89, ES = 0.04). Postprandial SBP was lower in HIIE compared to CON ( P = 0.04, ES = 0.50) and MIE ( P = 0.04, ES = 0.40), but not different between MIE and CON ( P = 0.52, ES = 0.11). Resting fat oxidation was increased in HIIE compared to CON ( P = 0.01, ES = 0.74) and MIE ( P = 0.05, ES = 0.51), with no difference between MIE and CON ( P = 0.37, ES = 0.24). Conclusion Neither exercise trial attenuated postprandial lipaemia. However, accumulating brief bouts of HIIE, but not MIE, reduced postprandial plasma glucose and SBP, and increased resting fat oxidation in adolescent boys and girls. The intensity of accumulated exercise may therefore have important implications for health outcomes in youth.

Recruiting patients to participate in health research is challenging, and most studies struggle. Failure to recruit can jeopardise the quality of research, and threatens efforts to improve healthcare. Despite this, recruitment materials tend to be conservatively designed and unimaginative. One reason for this is ethical concerns regarding the risk of coercion and offence posed by recruitment materials. The OXTEXT research programme gave patients a leading role in the design of new recruitment materials, in an area (mental health) where stigma and discrimination make ethical risks particularly acute. We discovered that our patient-designed recruitment materials were much bolder than usual, and they put the existing ethical boundaries to the test. The materials were effective and well liked – patients regarded them as neither unacceptable nor coercive. This suggests we may need to rethink the ethics of recruitment to research such that we permit more creative recruitment materials. In addition, it suggests a new role for patient input into research as designers of recruitment materials.

The purpose of this study was to assess the acute effect of high-intensity interval exercise (HIIE) and moderate-intensity exercise (MIE) on glucose tolerance, insulin sensitivity and fat oxidation in young boys. Eleven boys (8.8 ± 0.8 y) completed three conditions: 1) HIIE; 2) work-matched MIE; and 3) rest (CON) followed by an oral glucose tolerance test (OGTT) to determine glucose tolerance and insulin sensitivity (Cederholm index). Fat oxidation was measured following the OGTT using indirect calorimetry. There was no effect for condition on plasma [glucose] and [insulin] area under the curve (AUC) responses following the OGTT (P 0.09). However, there was a "trend" for a condition effect for insulin sensitivity with a small increase after HIIE (P = 0.04, ES = 0.28, 9.7%) and MIE (P = 0.07, ES = 0.21, 6.5%) compared to CON. There was an increase in fat oxidation AUC following HIIE (P = 0.008, ES = 0.79, 38.9%) compared to CON, but with no differences between MIE and CON and HIIE and MIE (P 0.13). In conclusion, 7- to 10-year-old boys may have limited scope to improve insulin sensitivity and glucose tolerance after a single bout of HIIE and MIE. However, fat oxidation is augmented after HIIE but not MIE.

This study used priming exercise in young boys to investigate (i) how muscle oxygen delivery and oxygen utilization, and muscle activity modulate oxygen uptake kinetics during exercise; and (ii) whether the accelerated oxygen uptake kinetics following priming exercise can improve exercise tolerance. Seven boys that were aged 11.3 ± 1.6 years completed either a single bout (bout 1) or repeated bouts with 6 min of recovery (bout 2) of very heavy-intensity cycling exercise. During the tests oxygen uptake, muscle oxygenation, muscle electrical activity and exercise tolerance were measured. Priming exercise most likely shortened the oxygen uptake mean response time (change, ±90% confidence limits; –8.0 s, ±3.0), possibly increased the phase II oxygen uptake amplitude (0.11 L·min−1, ±0.09) and very likely reduced the oxygen uptake slow component amplitude (–0.08 L·min−1, ±0.07). Priming resulted in a likely reduction in integrated electromyography (–24% baseline, ±21% and –25% baseline, ±19) and a very likely reduction in Δ deoxyhaemoglobin/Δoxygen uptake (–0.16, ±0.11 and –0.09, ±0.05) over the phase II and slow component portions of the oxygen uptake response, respectively. A correlation was present between the change in tissue oxygenation index during bout 2 and the change in the phase II (r = –0.72, likely negative) and slow component (r = 0.72, likely positive) oxygen uptake amplitudes following priming exercise, but not for muscle activity. Exercise tolerance was likely reduced (change –177 s, ±180) following priming exercise. The altered phase II and slow component oxygen uptake amplitudes in boys following priming exercise are linked to an improved localised matching of muscle oxygen delivery to oxygen uptake and not muscle electrical activity. Despite more rapid oxygen uptake kinetics following priming exercise, exercise tolerance was not enhanced.

Short stature and later maturation of youth artistic gymnasts are often attributed to the effects of intensive training from a young age. Given limitations of available data, inadequate specification of training, failure to consider other factors affecting growth and maturation, and failure to address epidemiological criteria for causality, it has not been possible thus far to establish cause–effect relationships between training and the growth and maturation of young artistic gymnasts. In response to this ongoing debate, the Scientific Commission of the International Gymnastics Federation (FIG) convened a committee to review the current literature and address four questions: (1) Is there a negative effect of training on attained adult stature? (2) Is there a negative effect of training on growth of body segments? (3) Does training attenuate pubertal growth and maturation, specifically, the rate of growth and/or the timing and tempo of maturation? (4) Does training negatively influence the endocrine system, specifically hormones related to growth and pubertal maturation? The basic information for the review was derived from the active involvement of committee members in research on normal variation and clinical aspects of growth and maturation, and on the growth and maturation of artistic gymnasts and other youth athletes. The committee was thus thoroughly familiar with the literature on growth and maturation in general and of gymnasts and young athletes. Relevant data were more available for females than males. Youth who persisted in the sport were a highly select sample, who tended to be shorter for chronological age but who had appropriate weight-for-height. Data for secondary sex characteristics, skeletal age and age at peak height velocity indicated later maturation, but the maturity status of gymnasts overlapped the normal range of variability observed in the general population. Gymnasts as a group demonstrated a pattern of growth and maturation similar to that observed among short-, normal-, late-maturing individuals who were not athletes. Evidence for endocrine changes in gymnasts was inadequate for inferences relative to potential training effects. Allowing for noted limitations, the following conclusions were deemed acceptable: (1) Adult height or near adult height of female and male artistic gymnasts is not compromised by intensive gymnastics training. (2) Gymnastics training does not appear to attenuate growth of upper (sitting height) or lower (legs) body segment lengths. (3) Gymnastics training does not appear to attenuate pubertal growth and maturation, neither rate of growth nor the timing and tempo of the growth spurt. (4) Available data are inadequate to address the issue of intensive gymnastics training and alterations within the endocrine system. Electronic supplementary material The online version of this article (doi:10.1007/s40279-013-0058-5) contains supplementary material, which is available to authorized users.

Use of the Surgical Safety Checklist (SSC) has blossomed since a landmark publication showed improved morbidity and mortality with its implementation. Parallel to increasing use of the SSC is a growing body of research investigating the effect of the SSC on the safety of care delivered. Nevertheless, at least one study shows an inconsistent degree of effect on outcomes. Others have investigated the impact of modifications of the SSC tailored to different clinical settings, as Morgan et al. show in their study, ‘‘Surgical safety checklist: implementation in an ambulatory surgical facility’’, in this issue of the Journal. The purpose of this study was ‘‘to add ambulatory carespecific items to the checklist, to assess adherence to safety checklist items, and to examine the impact of the SSC on safety attitudes and important patient outcomes’’ – all in an ambulatory surgical centre. On first thought, this is a logical concept, given that more and more procedures are being carried out on an ambulatory basis. What distinguishes this study from others that have investigated the impact of a SSC on various outcomes is the ambulatory scope and application of a modified SSC to this unique clinical environment. The primary outcome of the study consisted of two end points obtained through telephone interviews with patients on postoperative day one: (1) severity of pain (assessed on a scale of 1-10) and (2) incidence of postdischarge nausea/vomiting (PDNV). Secondary outcomes included the ‘‘incidence of perioperative antibiotic timing, use of regional anesthesia/ analgesia, length of stay, and the number of hospital admissions’’. Despite engaging a multidisciplinary team (consisting of nurses, surgeons, and anesthesiologists) to identify ambulatory-specific factors for inclusion on a modified SSC, clinically relevant differences in the primary and secondary outcomes were not achieved. Why did this occur? The authors identify several possible reasons for lack of effect with their well-intentioned ambulatory SSC: too many additions creating an unwieldy tool, issues with perceived importance of the new items by perioperative staff using the modified SSC, and low rates of overall checklist completion. Though many possible explanations exist, one must ultimately question if the SSC — with its recognized effect on mortality — can be expected to influence ambulatory outcomes like pain scores and PDNV. In their recent review of how and why checklists work, Weiser and Berry detail two main types of checklists. ‘‘Read-do’’ checklists are also known as ‘‘call-doresponse’’ or ‘‘verbal action and confirmation’’. These checklists are used by one person to identify ‘‘items to consider or tasks to accomplish’’, much like a grocery list or a ‘‘cook book’’. ‘‘Challenge-confirm’’ — also known as ‘‘verbal challenge and response’’ — checklists are generally more formalized and are used by two or more individuals, for example, a flight captain and co-pilot completing pre-takeoff checks. With this type of checklist, the reader of the checklist ‘‘challenges’’ another team member to ‘‘confirm’’ completion of each task in a communication format that is scripted to minimize confusion and maximize efficiency. Many checklists in industry and healthcare are a combination of ‘‘read-do’’ and ‘‘challenge-confirm’’, but use of a checklist (like the SSC) should be much more than simply ‘‘double checking’’, which has been described as the use of ‘‘one fallible person (to) monitor the work of another imperfect C. L. Pysyk, MD (&) Department of Anesthesiology, General Campus, The Ottawa Hospital, 501 Smyth Rd., Critical Care Wing 1401, Ottawa, ON K1H 8L6, Canada e-mail: cpysyk@toh.on.ca

SummaryService user memoirs are frequently reviewed in The Psychiatrist and other related journals. Some academic publications include first-hand accounts of mental ill health, and there is a lively market for autobiographical books and articles about mental illness. But clinicians already have extensive contact with service users and it might seem unlikely that they have much to gain from reading memoirs. In this article I suggest that the greater depth of reflection in published memoirs means clinicians do in fact have something to learn. I illustrate my argument by showing how memoirs cast a light on the world of information and conclude by suggesting reasons why memoirs raise issues that are of increasing clinical importance.

For ‘The Year that Was—2015’, I have selected 2 papers which review aspects of aerobic training. Studies of pediatric aerobic training generally focus on the effects of constant intensity exercise training (CIET) programs on peak oxygen uptake (VO2). The first paper has been chosen because it provides, for the first time, both a systematic review and a meta-analysis of the efficacy of high-intensity interval training (HIIT) in improving health-related fitness in adolescents. The second paper has been selected because it not only reviews both generic and sport-specific aerobic training studies of young team sport athletes, but also applies the analysis to the design of an evidence-based model of young athlete development. However, the primary reasons for highlighting these reviews is that they expose gaps in our knowledge of youth aerobic trainability, particularly between ‘pure’ and ‘applied’ pediatric sport science. They also identify areas where further research and appropriate data interpretation in relation to chronological age and biological maturation are required.

Research in paediatric exercise metabolism has been constrained by being unable to interrogate muscle in vivo . Conventionally, research has been limited to the estimation of muscle metabolism from observations of blood and respiratory gases during maximal or steady state exercise and the analysis of a few muscle biopsies taken at rest or post-exercise. The purpose of this paper is to review how the introduction of 31 P-magnetic resonance spectroscopy and breath-by-breath oxygen uptake kinetics studies has contributed to current understanding of exercise metabolism during growth and maturation. Methodologically robust studies using 31 P-magnetic resonance spectroscopy and oxygen uptake kinetics with children are sparse and some data are in conflict. However, it can be concluded that children respond to exercise with enhanced oxygen utilization within the myocyte compared with adults and that their responses are consistent with a greater recruitment of type I muscle fibres. Changes in muscle metabolism are age, maturation- and sex-related and dependent on the intensity of the exercise challenge. The introduction of experimental models such as “priming exercise” and “work-to-work” transitions provide intriguing avenues of research into the mechanisms underpinning exercise metabolism during growth and maturation.

Miklowitz DJ, Price J, Holmes EA, Rendell J, Bell S, Budge K, Christensen J, Wallace J, Simon J, Armstrong NM, McPeake L, Goodwin GM, Geddes JR. Facilitated Integrated Mood Management for adults with bipolar disorder. Bipolar Disord 2012: 14: 185–197. © 2012 The Authors. Journal compilation © 2012 John Wiley & Sons A/S. Objectives: We describe the development of a five-session psychoeducational treatment, Facilitated Integrated Mood Management (FIMM), which contains many of the core elements of longer evidence-based psychosocial treatments for bipolar disorder. FIMM incorporated a novel mood monitoring program based on mobile phone technology. Methods: Adult patients with bipolar I and II disorders (N = 19) received six sessions (Pilot I: n = 14) or five sessions (Pilot II: n = 5) of FIMM with pharmacotherapy. Treatment facilitators were novice counselors who were trained in a three-day workshop and supervised for six months. FIMM sessions focused on identifying early signs of recurrence, maintaining regular daily and nightly routines, rehearsing mood management strategies, maintaining adherence to medications, and education about substance abuse. Patients sent daily text messages or e-mails containing ratings of their mood and sleep, and weekly messages containing self-ratings on the Quick Inventory of Depressive Symptomatology (QIDS) and the Altman Self Rating Mania Scale (ASRM). Patients also completed a weekly mood management strategies questionnaire. Results: Of the 19 patients, 17 (89.5%) completed FIMM in an average of 9.2 ± 3.4 weeks (Pilot I) and 7.6 ± 0.9 weeks (Pilot II). Patients reported stable moods on the QIDS and ASRM over a 120-day period, and on average responded to 81% of the daily message prompts and 88% of the weekly QIDS and ASRM prompts. Facilitators maintained high levels of fidelity to the FIMM manual. Patients’ knowledge of mood management strategies increased significantly between the first and last weeks of treatment. Conclusions: Patients with bipolar disorder can be engaged in a short program of facilitated mood management. The effects of FIMM on the course of bipolar disorder await evaluation in randomized trials. The program may be a useful adjunct to pharmacotherapy in community centers that cannot routinely administer full courses of psychosocial treatment.

This study tested the hypothesis that pulmonary VO₂ kinetics would be slowed during 'work-to-work' exercise in adults but not in children. Eight boys (mean age=12.5 ± 0.5 years) and nine men completed very heavy step transitions initiated from either 'unloaded' pedalling (U→VH) or unloaded-to-moderate cycling (i.e. U→M to M→VH). The phase II τ was significantly (p

This study tested the hypothesis that the VO2 kinetic response would be slowed in untrained (UT) but not trained (T) teenage participants whilst cycling at 115 rev min(-1) compared to 50 rev min(-1). Eight UT and seven T boys completed two square-wave transitions to very heavy-intensity exercise pedalling at 50 rev min(-1) and 115 rev min(-1). In UT at the higher pedal rate, the phase II VO2 was significantly (P0.01) slower (50 rev min(-1): 32 ± 5 vs. 115 rev min(-1): 42 ± 11 s) and the relative VO2 slow component was significantly (P0.01) elevated (50 rev min(-1): 10 ± 3 vs. 115 rev min(-1): 16 ± 5%). The phase II VO2 (50 rev min(-1): 26 ± 4 vs. 115 rev min(-1): 22 ± 6s) and relative VO2 slow component (50 rev min(-1): 14 ± 5 vs. 115 rev min(-1): 17 ± 3%) were unaltered by pedal rate in T (P0.05). These data are consistent with the notion that VO2 kinetics are influenced by muscle fibre recruitment in youth but this effect is attenuated in endurance trained teenage boys.

The present study examined the effect of priming exercise on O2 uptake (V̇o2) kinetics during subsequent very heavy exercise in eight 9- to 13-yr-old boys. We hypothesised that priming exercise would 1) elevate muscle O2 delivery prior to the subsequent bout of very heavy exercise, 2) have no effect on the phase II V̇o2 τ, 3) elevate the phase II V̇o2 total amplitude, and 4) reduce the magnitude of the V̇o2 slow component. Each participant completed repeat 6-min bouts of very heavy-intensity cycling exercise separated by 6 min of light pedaling. During the tests V̇o2, muscle oxygenation (near infrared spectroscopy), and cardiac output (Q̇) (thoracic impedance) were determined. Priming exercise increased baseline muscle oxygenation and elevated Q̇ at baseline and throughout the second exercise bout. The phase II V̇o2 τ was not altered by priming exercise ( bout 1: 22 ± 7 s vs. bout 2: 20 ± 4 s; P = 0.30). However, the time constant describing the entire V̇o2 response from start to end of exercise was accelerated ( bout 1: 43 ± 8 s vs. bout 2: 36 ± 5 s; P = 0.002) due to an increased total phase II V̇o2 amplitude ( bout 1: 1.73 ± 0.33 l/min vs. bout 2: 1.80 ± 0.59 l/min; P = 0.002) and a reduced V̇o2 slow component amplitude ( bout 1: 0.18 ± 0.08 l/min vs. bout 2: 0.12 ± 0.09 l/min; P = 0.048). These results suggest that phase II V̇o2 kinetics in young boys is principally limited by intrinsic muscle metabolic factors, whereas the V̇o2 total phase II and slow component amplitudes may be O2 delivery sensitive.

Gastric emptying rate during exercise has been documented in adult athletes, but not in younger athletes because of the utilization of invasive techniques. However, magnetic resonance imaging (MRI) is a noninvasive alternative. The aim of this study was to pilot the sequencing of MRI to a typical fluid intake strategy, in order to assess the viability of the procedure. Therefore, we compared the gastric emptying rate of water and a carbohydrate drink in three well-trained 17-year-old cyclists using MRI. Each participant cycled 4 bouts of 15 minutes each at moderate intensity followed by a ∼15-minute time trial. Water or carbohydrate drinks were distributed in amounts of 200–250 mL. After an initial baseline MRI scan, cyclists ingested the first drink, cycled 15 minutes, followed by an MRI scan to assess remaining gastric volume. This feeding-exercise-scanning protocol was repeated thereafter. Relative to the initial volume at the start of the time trial, 69% and 72% of water and carbohydrate emptied during the time trial. MRI appears to be a feasible technique to assess gastric emptying rates in youth cyclists.

Prepubertal boys' greater aerobic fitness (peak V O(2)) has been attributed to their larger lean body mass (LBM); this bestowing a greater heart size and consequent larger maximum cardiac output. No difference in peak arterio-venous (A-VO(2)) difference is thought to exist. However other work indicates that boys' aerobic fitness remains 5% higher even after controlling for differences in LBM. Consequently the purpose of this study was to investigate whether peak V O(2), heart size, peak cardiac output and peak A-VO(2) difference would be comparable between a group of boys and girls with a similar LBM. A group of 9 prepubertal boys and 9 prepubertal girls with a similar mean LBM (27.0+/-1.4 boys vs. 27.0+/-2.0 kg girls) were selected. Left ventricular mass (LVM) and end diastolic volume (LVEDV) were measured using cardiac magnetic resonance imaging. Peak V O(2) was determined on a cycle ergometer following an incremental exercise protocol to exhaustion, and cardiac output was recorded using thoracic bioimpedance. Boys' peak V O(2) (1.41+/-0.18 L min(-1) vs. 1.23+/-0.08 L min(-1)) and A-VO(2) difference (14.8+/-2.1 mL 100mL(-1) vs. 12.6+/-1.6 mL 100mL(-1)) were significantly (p

Twelve 11-year-old girls (six lean, six overweight) were given meals in the laboratory and at school for 5 days, with exercise imposed for 2 days and sedentary activities on another 2 days in counterbalanced sequences. During a preliminary visit, the FLEX heart rate method was used to predict individual exercise durations eliciting 1.5 MJ energy expenditure. Morning and afternoon cycling exercise was subsequently imposed in the laboratory on 2 consecutive days as part of the 5-day intervention. Energy intake was measured via observation with meals being standardised between conditions, prepared and weighed by the research team. Hunger, fullness and desire to eat were rated by subjects immediately before and after meals and exercise. Energy expenditure was significantly elevated in the exercise condition, compared to sedentary. No exercise-induced differences in total daily or 5-day total energy intake were observed between groups or treatments. Overweight girls, however, rated their appetite immediately after exercise as being stronger than they rated it before exercise. In response to exercise-induced energy expenditure, 11-year old overweight and lean girls did not elevate their energy intake over a 5-day period.

Oded Bar-Or’s hypothesis that children may be “metabolic non-specialists”, even when engaging in specialized sports, has stimulated the study of paediatric exercise metabolism since the publication of his classic text Pediatric sports medicine for the practitioner in 1983. Evidence drawn from several methodologies indicates an interplay of anaerobic and aerobic exercise metabolism in which children have a relatively higher metabolic contribution from oxidative energy pathways than adolescents or adults, whereas there is a progressive increase in glycolytic support of exercise with age, at least into adolescence and possibly into young adulthood. The picture is generally consistent but incomplete, as research with young people has been limited by both ethical and methodological constraints. The recent rigorous introduction of non-invasive techniques such as breath-by-breath respiratory gas analysis and magnetic resonance spectroscopy into paediatric exercise physiology promises to open up new avenues of research and generate unique insights into the metabolism of the exercising muscle during growth and maturation. It therefore appears that we might have available the tools necessary to answer some of the elegant questions raised by Professor Bar-Or over 25 years ago.

The jump performance of ten youth soccer players (mean age 15.8 years, s= 0.4) was assessed before and after 42 min of soccer-specific exercise performed on a non-motorized treadmill. A squat, countermovement, and drop jump were performed on a force platform and simultaneously surface EMG activity of four lower limb muscles was collected. Jump height deteriorated across all conditions with mean reductions of - 1.4 cm (s = 1.6; P0.05), - 3.0 cm (s = 2.9; P0.05), and -2.3 cm (s = 1.7; P0.01) in the squat, countermovement, and drop jump respectively. The impact force in the drop jump was the only force variable to show a significant change with fatigue (P0.05). Following the prolonged exercise, reductions in total muscle activity were non-significant for the squat jump, approached significance for the counter-ovement jump (P = 0.07), and achieved significance for the drop jump (P0.05). The results showed that completing soccer-specific exercise reduced performance in all jump tasks. Reductions in muscle activity were greatest for the drop jump, suggesting an influence of muscle stretch and loading on reduced muscle activity when fatigued.

To further understand the mechanism(s) explaining the faster pulmonary oxygen uptake $$(p{\dot{V}}\hbox{O}_{2})$$ kinetics found in children compared to adults, this study examined whether the phase II $$p{\dot{V}}\hbox{O}_{2}$$ kinetics in children are mechanistically linked to the dynamics of intramuscular PCr, which is known to play a principal role in controlling mitochondrial oxidative phosphorylation during metabolic transitions. On separate days, 18 children completed repeated bouts of moderate intensity constant work-rate exercise for determination of (1) PCr changes every 6 s during prone quadriceps exercise using 31P-magnetic resonance spectroscopy, and (2) breath by breath changes in $$p{\dot{V}}\hbox{O}_{2}$$ during upright cycle ergometry. Only subjects (n = 12) with 95% confidence intervals ≤±7 s for all estimated time constants were considered for analysis. No differences were found between the PCr and phase II $$p{\dot{V}}\hbox{O}_{2}$$ time constants at the onset (PCr 23 ± 5 vs. $$p{\dot{V}}\hbox{O}_{2}\ 23 \pm 4\,\hbox{s}, P=1.000)$$ or offset (PCr 28 ± 5 vs. $$p{\dot{V}}\hbox{O}_{2}\ 29 \pm 5\,\hbox{s},\, P=1.000)$$ of exercise. The average difference between the PCr and phase II $$p{\dot{V}}\hbox{O}_{2}$$ time constants was 4 ± 4 s for the onset and offset responses. Pooling of the exercise onset and offset responses revealed a significant correlation between the PCr and $$p{\dot{V}}\hbox{O}_{2}$$ time constants (r = 0.459, P = 0.024). The close kinetic coupling between the $$p{\dot{V}}\hbox{O}_{2}$$ and PCr responses at the onset and offset of exercise in children is consistent with our current understanding of metabolic control and suggests that an age-related modulation of the putative phosphate linked controller(s) of mitochondrial oxidative phosphorylation may explain the faster $$p{\dot{V}}\hbox{O}_{2}$$ kinetics found in children compared to adults.

The purpose of this study was to examine the age and sex associated differences in the eccentric/concentric functional ratio for the knee. Isokinetic concentric and eccentric knee extension and flexion was measured at 0.52 rad x s (-1) and 3.14 rad x s (-1) in 121 subjects. Other than mass there were no significant age-by-sex interaction effects for all variables examined. A significant velocity-by-age group effect was demonstrated for ECC (KF)/CON (KE) with higher ratios at 3.14 compared to 0.52 rad x s (-1). Females' CON (KF)/ECC (KE) was significantly lower than males at both velocities. Adults demonstrated significantly lower CON (KF)/ECC (KE) than the teenagers at 0.52 rad x s (-1) and lower than the prepubertal and teenager groups at 3.14 rad x s (-1). However, for ECC (KF)/CON (KE) at 3.14 rad x s (-1), prepubertal ratios were significantly lower than teenagers and adults. The results of the current study suggest that functional rather than conventional ratio should be used when examining knee stability. During fast velocity movements, prepubertal children have a lower capacity for generating eccentric compared to concentric torque. The lower CON (KF)/ECC (KE) ratio in adults appears to be due to a greater ability to generate large eccentric torques at all slow and fast movement velocities. The lower CON (KF)/ECC (KE) ratio in females is a product of lower concentric torque as opposed to high eccentric torque producing capability as previously thought.

Purpose:The purpose of the study was to assess the reliability and validity of a newly developed laboratory protocol to measure prolonged repeated-sprint ability (RSA) during soccer-specific exercise.Methods:To assess reliability, 12 youth soccer players age 15.2 ± 0.3 y performed 2 trials of a soccer-specific intermittent-exercise test (SSIET) separated by 3 months. The test was performed on a nonmotorized treadmill. A separate sample of 12 youth soccer players (15.2 ± 0.3 y) completed the SSIET while simultaneously HR, VO2, and blood lactate (BLa) were monitored. The SSIET was designed to replicate the demands of competing in one half of a soccer match while sprint performance was monitored. The test included a 5-s sprint every 2 min.Results:The mean coefficient of variation was 2.5% for the total distance covered during the SSIET and 3.8% for the total distance sprinted; measures of power output were less reliable (>5.9%). Participants covered 4851 ± 251 m during the SSIET, working at an average intensity of 87.5% ± 3.2% HRpeak and 70.2% ± 3.1% VO2peak, with ~7mmol/L BLa accumulation. A significant reduction (P < .05) in sprint performance was ob served over the course of the SSIET.Conclusion:The SSIET provided a reliable method of assessing prolonged RSA in the laboratory. The distance covered and the physiological responses during the SSIET successfully recreated the demands of competing in a soccer match.

UNLABELLED: The influence of age, sex, maturity, body size and body fatness on cardiac output (Q) and stroke volume (SV) during treadmill running at 2.22 m x s(-1) was examined longitudinally. Mass, stature, triceps and subscapular skinfold thickness, and oxygen uptake (VO2) were recorded and Q was estimated using the CO2 rebreathing technique on each of three annual measurement occasions. Maturity was assessed using the indices for pubic hair described by Tanner. At the onset, subjects were 11.3 (0.4) y of age and data were available from a total of 274 Q determinations with equal numbers from boys and girls. Age-, sex- and maturity-associated changes in Q and SV adjusted for differences in body size and fatness were examined using multilevel regression modelling within an allometric framework. Changes in Q in both sexes were essentially in direct proportion to body surface area but, even with anthropometric variables controlled for, girls demonstrated a lower SV than boys, which was compensated for by a higher heart rate (HR) at each observation. CONCLUSION: At a given level of submaximal exercise over the age range 11-13 y Q is directly related to body size in both sexes. With body size and fatness controlled for, boys have greater SVs than girls when exercising at the same absolute VO2, Q and treadmill running speed. Age and maturation do not exert independent effects on either Q or SV.

The health, fitness and other advantages of youth sports participation are well recognised. However, there are considerable challenges for all stakeholders involved— especially youth athletes—in trying to maintain inclusive, sustainable and enjoyable participation and success for all levels of individual athletic achievement. In an effort to advance a more unified, evidence-informed approach to youth athlete development, the IOC critically evaluated the current state of science and practice of youth athlete development and presented recommendations for developing healthy, resilient and capable youth athletes, while providing opportunities for all levels of sport participation and success. The IOC further challenges all youth and other sport governing bodies to embrace and implement these recommended guiding principles.

High-intensity interval training (HIIT) improves traditional cardiovascular disease (CVD) risk factors in adolescents, but no study has identified the influence of HIIT on endothelial and autonomic function in this group. Thirteen 13- to 14-yr-old adolescents (6 girls) completed six HIIT sessions over 2 wk. Each training session consisted of eight to ten 1-min repetitions of cycling at 90% peak power interspersed with 75 s of unloaded cycling. Traditional (triglycerides, cholesterol, glucose, insulin, and blood pressure) and novel [flow-mediated dilation (FMD), heart rate variability (HRV)] CVD risk factors were assessed in a fasted and postprandial state before (PRE), 1 day after (POST-1D), and 3 days after (POST-3D) training. Aerobic fitness was determined PRE and POST-3D. Two weeks of HIIT had no effect on aerobic fitness or traditional CVD risk factors determined in the fasted or postprandial state ( P > 0.15). Compared with PRE, fasted FMD was improved POST-1D [ P = 0.003, effect size (ES) = 0.70] but not POST-3D ( P = 0.32, ES = 0.22). Fasted FMD was greater POST-1D compared with POST-3D ( P = 0.04, ES = 0.48). Compared with PRE, postprandial FMD was greater POST-1D ( P < 0.001, ES = 1.01) and POST-3D ( P = 0.01, ES = 0.60). Fasted HRV was greater POST-1D ( P = 0.001, ES = 0.71) and POST-3D ( P = 0.02, ES = 0.44). The test meal lowered HRV in all laboratory visits ( P < 0.001, ES = 0.59), but there were no differences in postprandial HRV between visits ( P > 0.32 for all). Two weeks of HIIT enhanced endothelial function and HRV without improvements in traditional CVD risk factors. However, most of this favorable adaptation was lost POST-3D, suggesting that regularly performing high-intensity exercise is needed to maintain these benefits.

Aim To provide an evidence-based review of muscle metabolism changes with sex-, age- and maturation with reference to the development of youth sport performance. Methods A narrative review of data from both invasive and non-invasive studies, from 1970 to 2015, founded on personal databases supported with computer searches of PubMed and Google Scholar. Results Youth sport performance is underpinned by sex-, age- and maturation-related changes in muscle metabolism. Investigations of muscle size, structure and metabolism; substrate utilisation; pulmonary oxygen uptake kinetics; muscle phosphocreatine kinetics; peak anaerobic and aerobic performance; and fatigue resistance; determined using a range of conventional and emerging techniques present a consistent picture. Age-related changes have been consistently documented but specific and independent maturation-related effects on muscle metabolism during exercise have proved elusive to establish. Children are better equipped for exercise supported primarily by oxidative metabolism than by anaerobic metabolism. Sexual dimorphism is apparent in several physiological variables underpinning youth sport performance. As young people mature there is a progressive but asynchronous transition into an adult metabolic profile. Conclusions The application of recent developments in technology to the laboratory study of the exercising child and adolescent has both supplemented existing knowledge and provided novel insights into developmental exercise physiology. A sound foundation of laboratory-based knowledge has been established but the lack of rigorously designed child-specific and sport-specific testing environments has clouded the interpretation of the data in real life situations. The primary challenge remains the translation of laboratory research into the optimisation of youth sports participation and performance.

Aim: To determine the relationship between aerobic fitness (peak [image omitted] ) and the volume of visceral adipose tissue (VAT) in children. Methods: Participants were 30 males (13.7±0.5 y) and 22 females (13.5±0.5 y). Peak [image omitted] was determined using a continuous, incremental treadmill protocol to exhaustion. Abdominal VAT volume was measured by magnetic resonance imaging using multiple slices from vertebral levels L1–L5. Subcutaneous body fat measure was calculated as the sum of seven skinfolds (σ7SKF). Results: Females had significantly (p≤0.05) more VAT than males (1035±717.3 vs 678.6±361.5 cm3); however, male peak [image omitted] was higher (215±34 vs 182±20 ml/kg0.61/min). VAT was significantly (p≤0.05) negatively correlated with peak [image omitted] in both males (r= - 0.43) and females (r= - 0.45). Subcutaneous body fatness was significantly correlated with VAT in both males (r=0.74) and females (r=0.72), and was the single strongest determinant of VAT. Conclusion: Aerobic fitness is significantly inversely related to VAT, but subcutaneous body fatness is the single strongest determinant of VAT in children aged 13–14 y.

The aim of this study was to examine elbow flexion torque, muscle cross-sectional area (CSA), and leverage in boys and girls. Thirty-eight prepubertal children (9.6 ± 0.3 years) volunteered to participate. All performed isometric flexion actions at 10°, 50°, and 90° of elbow flexion. Magnetic resonance imaging was used to assess elbow flexor (EF) muscle CSA and brachialis moment arm lengths. No significant gender differences were observed for any of the variables studied. EF CSA was directly proportional to isometric torque at 50° and 90°. CSA explained between 47% and 57% of torque variance. Moment arm estimates explained 19% of the variance in isometric torque at 90°. These baseline data contribute to our understanding of factors influencing strength variation during childhood.