IOC consensus statement on elite youth athletes competing at the Olympic Games: essentials to a healthy, safe and sustainable paradigm.

With the pronounced ongoing growth of global youth sports, opportunities for and participation of youth athletes on the world sports stage, including the Olympic Games, are expected to escalate. Yet, adolescence is a vulnerable period of development and inherently dynamic, with non-linear and asynchronous progression of physical, physiological, psychological and social attributes. These non-concurrent changes within and between individuals are accompanied by irregular and unpredictable threats and impediments. Likewise, the evident age-based criteria and conventional path for those youth athletes deemed eligible candidates for the Olympic Games are not well or consistently defined. Furthermore, the unstructured and largely varying policies and practices across the sporting International Federations specific to youth participation underscore the need to establish a contemporary universal paradigm that would enable elite youth athletes to navigate an individualised healthy pathway to personal, athletic and sport success. First, we reviewed and summarised key challenges facing elite youth athletes and the relevant evidence fundamental to facilitating and supporting central aspects of health and well-being, while empowering safe, sustainable and positive engagement during athletic and personal advancement and competition. Second, we developed and present a modern elite youth athlete model that emphasises a child-centred, practical framework with corresponding guidelines and recommendations to protect health and well-being while safely and favourably managing international sport competition. Our proposed evidence-informed paradigm will enable and support individualised pathways for healthy, well-rounded and sustainable positive engagement while achieving sport success for youth contending or aiming to compete at world-class international sporting events.

The Influence of Acute Hypoxia on Oxygen Uptake and Muscle Oxygenation Kinetics During Cycling Exercise in Prepubertal Boys.

PURPOSE: To examine the effect of normobaric hypoxia on pulmonary oxygen uptake (V˙O2) and muscle oxygenation kinetics during incremental and moderate-intensity exercise in children. METHODS: Eight prepubertal boys (9-11 y) performed incremental cycle tests to exhaustion in both normoxia and hypoxia (fraction of inspired O2 of 15%) followed by repeat 6-minute transitions of moderate-intensity exercise in each condition over subsequent visits. RESULTS: Maximal oxygen uptake (V˙O2max) was reduced in hypoxia compared with normoxia (1.69 [0.20] vs 1.87 [0.26] L·min-1, P = .028), although the gas exchange threshold was not altered in absolute terms (P = .33) or relative to V˙O2max (P = .78). During moderate-intensity exercise, the phase II V˙O2 time constant (τ) was increased in hypoxia (18 [9] vs 24 [8] s, P = .025), with deoxyhemoglobin τ unchanged (17 [8] vs 16 [6], P ≥ .28). CONCLUSIONS: In prepubertal boys, hypoxia reduced V˙O2max and slowed V˙O2 phase II kinetics during moderate-intensity exercise, despite unchanged deoxyhemoglobin kinetics. These data suggest an oxygen delivery dependence of V˙O2max and moderate-intensity V˙O2 kinetics under conditions of reduced oxygen availability in prepubertal boys.

Is it Still Ok to be Ok? Mental Health Labels as a Campus Technology.

This article uses ethnography and coproduced ethnography to investigate mental health labels amongst university students in the UK. We find that although labels can still be a source of stigma, they are also both necessary and useful. Students use labels as 'campus technologies' to achieve various ends. This includes interaction with academics and administrators, but labels can do more than make student distress bureaucratically legible. Mental health labels extend across the whole student social world, as a pliable means of negotiating social interaction, as a tool of self-discovery, and through the 'soft-boy' online archetype, they can be a means of promoting sexual capital and of finessing romantic encounters. Labels emerge as flexible, fluid and contextual. We thus follow Eli Clare in attending to the varying degrees of sincerity, authenticity and pragmatism in dealing with labels. Our findings give pause to two sets of enquiry that are sometimes seen as opposed. Quantitative mental health research relies on what appear to be questionable assumptions about labels embedded in questionnaires. But concerns about the dialogical power of labels to medicalise students also appears undermined.

The development of a creative work rehabilitation organisation.

Work as therapy has a place in mental healthcare, but there is disagreement about how and why it might be helpful, and how best to conceptualise or represent those benefits. Over the last 50 years, occupational and industrial therapy sheltered workshops have been key elements in the provision of work activities in psychiatric settings, and community-based horticultural activities and creative craft work have offered additional approaches. Using archival material, interviews, witness seminars and personal reflections, this article charts the birth and initial growth of Restore, a charity providing creative work-based services in Oxfordshire between 1977 and 1988. Although Restore might be understood as a response to national trends in mental healthcare policy and research, its trajectory reflects local contingencies.

Innovation in mental health care: Bertram Mandelbrote, the Phoenix Unit and the therapeutic community approach.

Bertram Mandelbrote was Physician Superintendent and Consultant Psychiatrist at Littlemore Hospital in Oxford from 1959 to 1988. A humane pragmatist rather than theoretician, Mandelbrote was known for his facilitating style of leadership and working across organisational boundaries. He created the Phoenix Unit, an innovative admission unit run on therapeutic community lines which became a hub for community outreach. Material drawn from oral histories and witness seminars reflects the remarkably unstructured style of working on the Phoenix Unit and the enduring influence of Mandelbrote and fellow consultant Benn Pomryn's styles of leadership. Practices initiated at Littlemore led to a number of innovative services in Oxfordshire. These innovations place Mandelbrote as a pioneer in social psychiatry and the therapeutic community approach.

Happenstance and regulatory culture: the evolution of innovative community mental health services in Oxfordshire in the late twentieth century.

This paper uses co-produced historical material to explore the evolution of two innovative mental healthcare institutions that emerged in Oxfordshire in the 1960s. We highlight how the trajectories of both institutions were driven by chance events occurring within social environments, rather than emerging out of evidence or policy initiatives. Both institutions found a role for spontaneity and an openness to chance in the way they worked. We argue that this kind of institutional history would be unlikely today; the paper develops and uses the concept of regulatory culture to explain why. We suggest that the role of regulatory culture has been neglected in the history of psychiatry.

The processes and context of innovation in mental healthcare: Oxfordshire as a case study.

This article introduces the four following articles and the Classic Text. They describe the development of a sequence of innovative local mental health services in Oxfordshire, and explore the processes of innovation, led by the humane pragmatism practised by Dr Bertram Mandelbrote, who was Physician Superintendent at Littlemore Hospital in Oxford from 1959 to 1988. The articles describe emerging patterns of therapeutic community practice, and trace the events leading to a set of discrete service developments outside the hospital. Together, they suggest a positive role for chance in these developments, and a focus on the then prevailing national and local regulatory culture. The Classic Text by David Millard provides an overview of the origins of the therapeutic community movement.

Silver linings: how mental health activists can help us navigate wicked problems.

SUMMARY: This article explores how 'wicked problems' such as climate change might force psychiatry to rethink some of its fundamental ideas and ways of working, including clinical boundaries, understandings of psychopathology and ways of organising. We use ethnographic evidence to explore how mental health service 'survivor' activists are already rethinking some of these issues by therapeutically orienting themselves towards social problems and collective understandings of well-being, rejecting 'treatment as usual' approaches to distress. In this way we provide an example of the potential of activists to help psychiatry negotiate the climate crisis.

Sex-related differences in accumulated O2 deficit incurred by high-intensity rowing exercise during childhood and adolescence.

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 < 0.001) with boys exhibiting significantly higher AOD than girls from the age of 14 years (10-11.9 yr: 1.9 vs 1.9 L, 12-13.9 yr: 2.4 vs 2.7 L, 14-15.9 yr: 2.8 vs 4.6 L and 16-17.9 yr: 2.9 vs 5.2 L, in girls and boys respectively, p < 0.001). However, a sex difference was no longer significant when AOD was analysed using an allometric model including age and LBM (p = 0.885). Finally, significant correlations were found between AOD and MPO in boys and girls but with lower evidence in girls (r2 = 0.41 vs. 0.89). 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.

Allometric Scaling of Force-velocity Test Output Among Pre-pubertal Basketball Players.

Basketball is characterized by high-intensity episodes predominantly reliant on anaerobic metabolism. The force-velocity test enables individual determination of an optimal braking force and emerged as appropriate to estimate optimal peak power. It has rarely been used in youth basketball. This study aimed to examine the contribution of body size, composition, and biological maturation to interindividual variation in force-velocity test output among pre-pubertal basketball players. The sample consisted of 64 male participants (8.4-12.3 years). Stature, sitting height, body mass and two skinfolds were measured, and leg length estimated. Fat-free mass and lower limb volume were estimated from anthropometry. Age at peak height velocity was predicted from maturity offset. Optimal peak power was correlated with all body size descriptors (correlation: 0.541-0.700). Simple allometric models explained 30-47% of inter-individual variance, with fat-free mass being the best predictor of performance. Whole-body fat-free mass (as a surrogate for active muscle mass) plus the indicator of maturation emerged as the best proportional allometric model (53% explained variance). Even at pre-pubertal ages, the interpretation of the force-velocity test requires assessing the metabolically active component of body mass.

Influence of sex-specific concurrent changes in age, maturity status, and morphological covariates on the development of peak ventilatory variables in 10-17-year-olds.

PURPOSES: (i) To investigate the influence of concurrent changes in age, maturity status, stature, body mass, and skinfold thicknesses on the development of peak ventilatory variables in 10-17-year-olds; and, (ii) to evaluate the interpretation of paediatric norm tables of peak ventilatory variables. METHODS: Multiplicative multilevel modelling which allows both the number of observations per individual and the temporal spacing of the observations to vary was used to analyze the expired ventilation (peak [Formula: see text]) and tidal volume (peak VT) at peak oxygen uptake of 420 (217 boys) 10-17-year-olds. Models were founded on 1053 (550 from boys) determinations of peak ventilatory variables supported by anthropometric measures and maturity status. RESULTS: In sex-specific, multiplicative allometric models, concurrent changes in body mass and skinfold thicknesses (as a surrogate of FFM) and age were significant (p < 0.05) explanatory variables of the development of peak [Formula: see text], once these covariates had been controlled for stature had no additional, significant (p > 0.05) effect on peak [Formula: see text]. Concurrent changes in age, stature, body mass, and skinfold thicknesses were significant (p < 0.05) explanatory variables of the development of peak VT. Maturity status had no additional, significant (p > 0.05) effect on either peak [Formula: see text] or peak VT once age and morphological covariates had been controlled for. CONCLUSIONS: Elucidation of the sex-specific development of peak [Formula: see text] requires studies which address concurrent changes in body mass, skinfold thicknesses, and age. Stature is an additional explanatory variable in the development of peak VT, in both sexes. Paediatric norms based solely on age or stature or body mass are untenable.

Traditional and New Perspectives on Youth Cardiorespiratory Fitness.

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.

Importance of dimensional changes on glycolytic metabolism during growth.

PURPOSE: The 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. METHODS: Thirty-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. RESULTS: AODgly and [La]max increased while pHmin decreased linearly with LBM and MO (r2 = 0.46 to 0.72, p < 0.001). Moreover, AODgly was positively correlated with [La]max (r2 = 0.75, p < 0.001) and negatively correlated with pHmin (r2 = 0.77, p < 0.001). When AODgly was scaled for LBM, the coefficients of the relationships with blood markers drastically decreased by three to four times ([La]max: r2 = 0.24, p = 0.002; pHmin: r2 = 0.30, p < 0.001). Furthermore, by scaling AODgly for LBM + MO, the correlation coefficients with blood markers became even lower ([La]max: r2 = 0.12, p = 0.037; pHmin: r2 = 0.18, p = 0.009). However, MO-related additional changes accounted much less than LBM for the relationships between AODgly and blood markers. CONCLUSION: The results challenge previous reports of maturation-related differences in glycolytic energy turnover and suggest that changes in lean body mass are a more powerful influence than maturity status on glycolytic metabolism during growth.

Multilevel allometric modelling of maximum cardiac output, maximum arteriovenous oxygen difference, and peak oxygen uptake in 11-13-year-olds.

PURPOSES: To investigate longitudinally (1) the contribution of morphological covariates to explaining the development of maximum cardiac output ([Formula: see text] max) and maximum arteriovenous oxygen difference (a-vO2 diff max), (2) sex differences in [Formula: see text] max and a-vO2 diff max once age, maturity status, and morphological covariates have been controlled for, and, (3) the contribution of concurrent changes in morphological and cardiovascular covariates to explaining the sex-specific development of peak oxygen uptake ([Formula: see text]). METHODS: Fifty-one (32 boys) 11-13-year-olds had their peak [Formula: see text], maximum heart rate (HR max), [Formula: see text] max, and a-vO2 diff max determined during treadmill running on three annual occasions. The data were analysed using multilevel allometric modelling. RESULTS: There were no sex differences in HR max which was not significantly (p > 0.05) correlated with age, morphological variables, or peak [Formula: see text]. The best-fit models for [Formula: see text] max and a-vO2 diff max were with fat-free mass (FFM) as covariate with age, maturity status, and haemoglobin concentration not significant (p > 0.05). FFM was the dominant influence on the development of peak [Formula: see text]. With FFM controlled for, the introduction of either [Formula: see text] max or a-vO2 diff max to multilevel models of peak [Formula: see text] resulted in significant (p < 0.05) additional contributions to explaining the sex difference. CONCLUSIONS: (1) With FFM controlled for, there were no sex differences in [Formula: see text] max or a-vO2 diff max, (2) FFM was the dominant influence on the development of peak [Formula: see text], and (3) with FFM and either [Formula: see text] max or a-vO2 diff max controlled for, there remained an unresolved sex difference of ~ 4% in peak [Formula: see text].

The effects of two weeks high-intensity interval training on fasting glucose, glucose tolerance and insulin resistance in adolescent boys: a pilot study.

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 < 0.05). 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.