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Volume 36 (2024): Issue 3 (Aug 2024)

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Editor’s Notes

Craig A. Williams

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

Max E. Weston, Neil Armstrong, Bert Bond, Owen W. Tomlinson, Craig A. Williams, and Alan R. Barker

Purpose: To examine the effect of normobaric hypoxia on pulmonary oxygen uptake ( V ˙ O 2 ) 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 ˙ O 2 max ) 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 ˙ O 2 max (P = .78). During moderate-intensity exercise, the phase II V ˙ O 2 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 ˙ O 2 max and slowed V ˙ O 2 phase II kinetics during moderate-intensity exercise, despite unchanged deoxyhemoglobin kinetics. These data suggest an oxygen delivery dependence of V ˙ O 2 max and moderate-intensity V ˙ O 2 kinetics under conditions of reduced oxygen availability in prepubertal boys.

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Intensity and Appreciation of Sweet Taste Solutions Are Modulated by High-Intensity Aerobic Exercise in Adolescent Athletic Males

Alexandre-Charles Gauthier, Marc-Étienne Villeneuve, Mathieu Cournoyer, and Marie-Eve Mathieu

Purpose: Exercise seems to influence taste, but the effect of exercise on specific tastes is still to be elucidated among youths. Methods: Athlete boys aged 14–16 years were recruited. Participants (n = 19) ages ranged 14.7 (0.7) years, weight 59.6 (7.8) kg, and height of 173.4 (7.9) cm. Distinct taste tests were administered using low and high concentrations of sweet, salty, and bitter solutions before and after a 30-minute aerobic exercise session (70%–90% of estimated maximal heart rate). McNemmar tests, standard paired t tests, Wilcoxon signed-rank tests, and Cohen d effect size tests were used to analyze taste identification, intensity, and appreciation. Results: There were no significant differences in taste identification capacities after exercise. Participants perceived more intense (P = .037) and appreciated better (P = .004) the low-concentration sweet solution after exercise. Taste appreciation was increased for the high-concentration sweet solution (P = .009) after exercise. Effect sizes were moderate (0.516–0.776). Possible effects were noted for the intensity of salty solutions (P = .0501 and .0543). Conclusion: Following an exercise session, participants had increased perceived intensity and appreciation of sweet solutions. This adds new insights into how exercise influences taste in youths, a topic less documented compared with adults, suggesting further research into its impact on dietary choices is needed.

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Response to: Methodological Rigor in Reference Chart Development: A Comment on “Normative Reference Centiles for Sprint Performance in High-Level Youth Soccer Players: The Need to Consider Biological Maturity”

Ludwig Ruf, Stefan Altmann, Christian Kloss, and Sascha Härtel

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Methodological Rigor in Reference Chart Development: A Comment on “Normative Reference Centiles for Sprint Performance in High-Level Youth Soccer Players: The Need to Consider Biological Maturity”

Lorenzo Lolli

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Oxford Textbook of Children’s Sport and Exercise Medicine, Fourth Edition

Keith Tolfrey

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Are Young Female Basketball Players Adequately Prepared for a Force–Velocity Jumping and Sprinting Assessment?

Jessica Rial-Vázquez, Iván Nine, María Rúa-Alonso, Juan Fariñas, Roberto Fernández-Seoane, Pedro Jiménez-Reyes, Miguel Fernández-del-Olmo, and Eliseo Iglesias-Soler

Purpose: The aim of this study was to explore the interday reliability of mechanical variables obtained from the horizontal and vertical force–velocity (FV) profiles in adolescent female basketball players. If found to be reliable, the associations between FV parameters (theoretical maximal force, velocity, and power), squat jump (SJ) height, 30-m sprint, and change of direction (COD) times were evaluated. Methods: After familiarization, SJ against incremental loads, 30-m sprint, and 505-COD tests were obtained twice in 36 adolescent female basketball players (age = 15.4 [1.2] y). Results: Reliability for vertical FV parameters was unacceptable, whereas 505-COD times and FV horizontal parameters (except for theoretical maximal power) showed a moderate to high reliability. 505-COD time was correlated with FV horizontal parameters (range: r = −.821, −.451), and a large association was observed with both SJ height (r = −.678, −.600) and 30-m sprint time (r = .813, .858). Conclusions: Due to low levels of strength, our athletes were not adequately prepared to obtain a reliable vertical FV profile. Practitioners can expect acceptable reliability of the horizontal FV profile. Given the association between COD performance and SJ height and 30-m sprint time, we encouraged practitioners with limited equipment at their disposal to use COD and/or 30-m sprint tests.

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Independent and Combined Associations of Physical Activity and Screen Time With Biomarkers of Inflammation in Children and Adolescents With Overweight/Obesity

Yijian Ding and Xi Xu

Purpose: Inflammation regulation is important for obesity management and prevention of obesity-related diseases. This cross-sectional study aimed to analyze the independent and combined associations of physical activity and screen time with biomarkers of inflammation in children and adolescents with overweight/obesity. Method: A total of 1289 children and adolescents with overweight/obesity were included from the 2015 to 2018 National Health and Nutrition Examination Survey. Multivariable linear regressions were conducted for the association analyses. Results: For the independent associations, a negative dose-dependent relationship was demonstrated between physical activity and inflammatory biomarker high-sensitivity C-reactive protein (hsCRP) in adolescents with overweight/obesity (P < .001) but not children; screen time was not associated with hsCRP in both children and adolescents. No significant association was found between physical activity or screen time with other inflammatory biomarkers. For the combined associations, there was an interaction between physical activity and screen time on hsCRP in adolescents with overweight/obesity (P = .014). In addition, the negative association between physical activity and hsCRP was greater in boys compared with girls and in Hispanic and non-Hispanic Black individuals compared with non-Hispanic White individuals. Conclusion: This study demonstrated a combined association of physical activity and screen time with inflammatory biomarker hsCRP in adolescents with overweight/obesity.

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Physical Activity and Motor Skill Development During Early Childhood: Investigating the Role of Parent Support

Maeghan E. James, Kelly P. Arbour-Nicitopoulos, Matthew Kwan, Sara King-Dowling, and John Cairney

Purpose: This study examined the relationship between parent physical activity (PA) support and children’s motor skill development and PA during early childhood and explored the potential moderating effect of child PA and motor skills on these relationships. Methods: Participants (N = 589, 250 girls, meanage = 4.93 [0.59] y) were part of a larger, longitudinal cohort study. Motor skills were assessed using the Movement Assessment Battery for Children—Second Edition. Moderate to vigorous PA (MVPA) was measured using ActiGraph accelerometers. Five items were used to measure parent support frequency (1 = none, 3 = 3–4 times, 5 = daily). Moderation analyses were conducted to examine the moderating effect of MVPA and motor skills on the relationship between parent support and motor skills and MVPA, respectively. Results: Parent support was significantly related to motor skills (B = 14.45, P = .007), and child MVPA significantly moderated this relationship (B = −0.17, P = .021). The relationship between parent support and child MVPA did not reach significance (B = 2.89, P = .051); however, motor skills had a significant moderating effect (B = −0.08, P = .022). Conclusions: These novel findings suggest parent PA support is related to child motor skills and PA during early childhood, but this relationship is context dependent. Child-level characteristics should be considered in future parent PA support research.