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Bone Turnover Markers and Osteokines in Adolescent Female Athletes of High- and Low-Impact Sports Compared With Nonathletic Controls

Steven Kottaras, Joshua Stoikos, Brandon J. McKinlay, Izabella A. Ludwa, Andrea R. Josse, Bareket Falk, and Panagiota Klentrou

This study examined differences in resting concentrations of markers of bone formation and resorption, and osteokines between female adolescent (12–16 y) swimmers, soccer players, and nonathletic controls. Resting, morning blood samples were obtained after an overnight fast from 20 swimmers, 20 soccer players, and 20 nonathletic controls, matched for age. carboxyl-terminal cross-linking telopeptide of type I collagen (CTX), amino-terminal propeptide of type I collagen (P1NP), total osteocalcin (OC), sclerostin, osteoprotegerin (OPG), and receptor activator of nuclear factor kappa B ligand (RANKL) were analyzed in serum. After controlling for percent body fat, there were no significant differences between swimmers and nonathletic controls in any of the measured markers. In contrast, soccer players had significantly higher P1NP (89.5 [25.6] ng·mL−1), OC (57.6 [22.9] ng·mL−1), and OPG (1052.5 [612.6] pg·mL−1) compared with both swimmers (P1NP: 66.5 [20.9] ng·mL−1; OC: 24.9 [12.5] ng·mL−1; OPG: 275.2 [83.8] pg·mL−1) and controls (P1NP: 58.5 [16.2] ng·mL−1; OC: 23.2 [11.9] ng·mL−1; OPG: 265.4 [97.6] pg·mL−1), with no differences in CTX, sclerostin, and RANKL. These results suggest that bone formation is higher in adolescent females engaged in high-impact sports like soccer compared with swimmers and controls.

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Short-Term Muscle Power Is Related to Lower Limb Muscle Volume in Young Children

Steven J. Obst, Kaysie Florance, Luke Heales, Sasha Job, and Lee Barber

Purpose: Muscle power is a component of muscular fitness and is proportional to its volume. Reduced muscular fitness in children is linked to negative health outcomes. Associations between muscle volume (MV) and power have not been examined in young children and could reveal important insights into early neuromuscular development. Method: Forty-four children (2–8 y) completed 3 tests of short-term muscular power: repeated anaerobic sprint test, vertical jump, and horizontal jump. MV was assessed using 3D ultrasound for 3 lower limb muscles (rectus femoris, medial gastrocnemius, and tibialis anterior) and summed for across legs. Associations between muscular power and summed MV were assessed using Pearson correlation (r). Sex-based differences in muscular power and MV were assessed using 1-way analysis of covariance. Results: Moderate–strong associations (r = .57 − .87) were found between muscular power and summed MV. No differences were found between boys and girls for height, weight, MV, or muscular power. Conclusions: Young children who have larger lower limb muscles perform better at tasks dependent on short-term muscular power, such as running and jumping, compared with children with smaller muscles. Sex-based differences in short-term muscular power do not exist in young children and reflect similar anthropometry, including lower limb MV.

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A National Implementation Approach for Exercise as Usual Care in Pediatric and Adolescent Oncology: Network ActiveOncoKids

Miriam Götte, Regine Söntgerath, Gabriele Gauß, Joachim Wiskemann, Mirko Buždon, and Sabine Kesting

The diagnosis of cancer as well as accompanying acute and late effects of treatment are influencing physical activity behavior of patients with childhood cancer and survivors. Research has shown that a pediatric cancer diagnosis is associated with impairments of physical performance, and function, as well as reduced physical, and psychosocial, health conditions. From an ethical perspective, lack of knowledge of health care providers, lack of physical activity promotion, and environmental, and structural barriers to physical activity restrict children’s right to move and actively engage in physical activities. Network ActiveOncoKids is a German-wide initiative with the main goal of enabling children, adolescents, and young adults with exercise opportunities during and after cancer treatment. Since the network’s foundation in 2012, Network ActiveOncoKids focuses on: (1) physical activity support for patients and families, (2) policy change to establish structures and guidelines, and (3) generating evidence through scientific projects. The purpose of this paper is to present an overview of Network ActiveOncoKids structure, aims, and projects. This topical review will highlight the network’s structural development, research work, and implementation progress of exercise programs for patients with pediatric cancer and survivors, link international collaborations, and discuss future directions.

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Bidirectional Daily Associations Between Accelerometer-Measured Sleep and Physical Activity in Brazilian High School Students

Luís Eduardo Argenta Malheiros, Bruno Gonçalves Galdino da Costa, Marcus Vinícius Veber Lopes, Érico Pereira Gomes Felden, and Kelly Samara da Silva

Purpose: This study analyzed day-to-day estimates of bidirectional associations between sleep parameters and intensity-specific physical activity and assessed whether the timing of physical activity influences these relationships. Methods: The sample was comprised of 651 high school students (51.2% female, 16.33 [1.0] y old) from southern Brazil. Physical activity and sleep were measured using accelerometers. Multilevel models were applied to test associations of nocturnal total sleep time, onset, and efficiency with moderate to vigorous and light (LPA) physical activity. Results: Higher engagement in moderate to vigorous physical activity and LPA was associated with increased total sleep time, and this effect was greater when physical activity was performed in the morning. Morning and evening LPA were associated with increased sleep efficiency and reduced total sleep time, respectively. Practice of LPA in the morning leads to early sleep onset, whereas evening LPA was associated with later onset. Higher total sleep time and later sleep onset were associated with lower moderate to vigorous physical activity and LPA on the following day. However, higher sleep efficiency was associated with increased LPA. Conclusion: The relationship between sleep parameters and physical activity is bidirectional and dependent on physical activity intensity and timing.

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Change of Direction Speed in Youth Male Soccer Players: The Predictive Value of Anthropometrics and Biological Maturity

Yassine Negra, Senda Sammoud, Alan M. Nevill, and Helmi Chaabene

This study aimed to develop the optimal allometric body size/shape and a biological maturity model that predicted the change of direction (CoD) mean speed performance in youth male soccer players. One-hundred and fifteen youth soccer players (age: 12.4 [1.3] y) participated in this study. The 505 test was used to assess CoD mean speed performance. Anthropometric measurements comprised body height (cm), sitting height (cm), body mass (kg), fat mass (kg), lower limb length (cm), thigh length (cm), leg length (cm), foot length (cm), thigh girth (cm), and calf girth (cm). The maturity status was determined based on the maturity offset method. To identify size/shape and maturity characteristics associated with CoD speed performance, we computed a multiplicative allometric log-linear regression model, which was refined using backward elimination. The multiplicative allometric model exploring the association between 505 CoD mean speed performance and the different anthropometric characteristics in youth soccer players estimated that fat mass (P < .001), sitting height (P = .02), and maturity offset (P = .004) are the key predictors. More specifically, youths who are more mature and have a lower fat mass and a shorter trunk length, are likely to achieve a better CoD mean speed performance. These findings highlight the relevance of considering anthropometric and maturity characteristics in youth soccer players to support talent identification.

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Volume 34 (2022): Issue 2 (May 2022)

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Sex-Related Differences in Oxygen Consumption Recovery After High-Intensity Rowing Exercise During Childhood and Adolescence

Joffrey Bardin, Hugo Maciejewski, Allison Diry, Claire Thomas, and Sébastien Ratel

Purpose: To determine sex-related differences in oxygen consumption ( V ˙ O 2 ) recovery after high-intensity exercise during childhood and adolescence. Methods: Forty-two boys and 35 girls (10–17 y) performed a 60-second all-out test on a rowing ergometer. Postexercise V ˙ O 2 recovery was analyzed from (1) the V ˙ O 2 recovery time constant obtained from a biexponential model (τ1 V ˙ O 2 ) and (2) excess postexercise oxygen consumption calculated over a period of 8 minutes (EPOC8) and until τ 1 V ˙ O 2 was reached (EPOCτ 1). Multiplicative allometric modeling was used to assess the concurrent effects of body mass or lean body mass, and age on EPOC8 and EPOCτ 1. Results: EPOC8 increased significantly more in boys from the age of 14 years. However, the sex difference was no longer significant when EPOC8 was analyzed using an allometric model including body mass + age or lean body mass + age. In addition, despite a greater increase in EPOCτ 1 in boys from the age of 14 years, τ 1 V ˙ O 2 was not significantly different between sexes whatever age. Conclusion: While age and lean body mass accounted for the sex-related differences of EPOC during childhood and adolescence, no significant effect of age and sex was observed on the V ˙ O 2 recovery time constant after high-intensity exercise.

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Martial Arts Training for Boys With Duchenne Muscular Dystrophy

Maarten K.N. Stessel, Imelda J.M. de Groot, and Mariska M.H.P. Janssen

Purpose: The primary aim of this pilot study was to investigate the safety and feasibility of a 3-month martial arts-based training (MAT) program for patients with Duchenne muscular dystrophy (DMD). The secondary aim was to examine changes in physical and psychosocial abilities after participating in the MAT program. Methods: Twelve patients with DMD (10 ambulant and 2 nonambulant) were included. The MAT program was evaluated on feasibility and safety. Changes in physical abilities were measured using the Motor Function Measure, Performance of Upper Limb scale, and the North Star Ambulatory Assessment. Changes in psychosocial abilities were measured using the Strength and Difficulties Questionnaire, Personal Adjustment and Role Skills for DMD, and the Self-Perception Profile for Children/Adolescents. Results: Two participants did not complete the MAT program. Attendance rate for the 10 remaining participants was 91%. Eleven falls were reported during the training, but these falls did not result in injuries. Therefore, the MAT program was found feasible and safe. After completing the MAT program, most participants showed an improvement of their psychosocial abilities, and their physical abilities did not show deterioration. Conclusion: The MAT program is feasible and safe for boys with DMD.

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Practices and Procedures in Clinical Pediatric Exercise Laboratories in North America

Kelli M. Teson, Jessica S. Watson, Wayne A. Mays, Sandy Knecht, Tracy Curran, Paul Rebovich, David D. Williams, Stephen M. Paridon, and David A. White

Interinstitutional differences in clinical pediatric exercise laboratory (CPEL) practices may affect patient care and efficacy of multicenter research. Purpose: To describe current practices/procedures in CPELs and explore differences in CPELs employing exercise physiologists to those that do not. Methods: A 40-item survey was distributed to CPELs in North America focusing on (1) staffing; (2) exercise stress testing (EST) volumes, reporting, and interpretation; and (3) EST procedures/protocols. Results: Of the 55 responses, 89% were in the United States, 85% were children’s hospitals with university affiliation, and 58% were cardiology specific. Exercise physiologists were employed in 56% of CPELs, and 78% had master’s degrees or higher. Certifications were required in most CPELs (92% emergency life-support, 27% professional, and 21% clinical). Median volume was 201 to 400 ESTs per year, 80% used treadmill, and 10% used cycle ergometer as primary modalities. Ninety-three percent of CPELs offered metabolic ESTs, 87% offered pulmonary function testing, 20% used institution-specific EST protocols, and 72% offered additional services such as cardiac/pulmonary rehabilitation. CPELS staffing exercise physiologists performed higher volumes of ESTs (P = .004), were more likely to perform metabolic ESTs (P = .028), participated in more research (P < .001), and provided services in addition to ESTs (P = .001). Conclusions: Heterogeneity in CPELs staffing and operation indicates need for standardization.

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Repeated Sprint Protocols With Standardized Versus Self-Selected Recovery Periods in Elite Youth Soccer Players: Can They Pace Themselves? A Replication Study

Florian A. Engel, Stefan Altmann, Hamdi Chtourou, Alexander Woll, Rainer Neumann, Tomer Yona, and Billy Sperlich

Purpose: Replicating the studies of Gibson et al and Brownstein et al to assess performance, and physiological, and perceived variables during a repeated sprint protocol (RSP) with standardized versus self-selected recovery in youth soccer players. Methods: Nineteen male soccer players (age 13.1 [1.3] y) completed 2 separate RSPs. RSP1: 10 × 30-m sprints with 30-second recovery and RSP2: 10 × 30-m sprints interspersed with self-selected recovery periods. Mean time of both 10 × 30-m RSPs and self-selected recovery periods of RSP2 were assessed. Heart rate, blood lactate concentration, and rates of perceived exertion were measured following RSPs. Results: RSP2 revealed longer recovery periods (RSP1: 30.0 [0.0] s; RSP2: 39.0 [7.7] s; P < .001; effect size d = 1.648) with shorter repeated sprint time (mean 30-m sprint time: RSP1: 4.965 [0.256] s; RSP2: 4.865 [0.227] s; P = .014; d = 0.414). Blood lactate concentration (P = .002–.005; d = 0.730–0.958), heart rate (P < .001; d = 1.353), and rates of perceived exertion (RSP1: 14.9 [1.9]; RSP2: 12.9 [2.1]; P = .016; d = 1.046) were higher following RSP1. Conclusion: In contrast to the original studies, the present replication study demonstrated that self-selected recovery periods during a RSP leads to better repeated sprint performance compared with standardized recovery periods in youth soccer players. The better repeated sprint performance with individual recovery durations in RSP2 was achieved with less physiological and perceived effort.