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"Peak height velocity"

Sylvia Moeskops, Jon L Oliver, Paul J Read, John B Cronin, Gregory D Myer, G Gregory Haff, Rhodri S Lloyd
To investigate the within- and between-session reliability of the isometric mid-thigh pull (IMTP) in pre- and post-peak height velocity (PHV) female athletes. Nineteen pre- and nineteen post-PHV athletes performed bilateral IMTPs using a custom-designed isometric testing system. Participants attended three separate testing-sessions, and performed three trials within each session. Peak force, relative peak force, force at 30, 50, 90, 100, 150, 200, and 250 milliseconds, rate of force development (RFD) within time-specific bands, time to peak force (TPF), and time to peak rate of force development (TPRFD) were obtained for analysis...
March 15, 2018: Journal of Strength and Conditioning Research
David Bender, Jeremy R Townsend, William Vantrease, Autumn C Marshall, Ruth N Henry, Stephen Heffington, Kent D Johnson
The purpose of this study was to examine the effects of acute beetroot juice (BR) administration on repeated sprint performance and isometric force production in adolescent males. Twelve male adolescents (16.8 ± 1.0 yrs; 178.8 ± 9.2 cm; 74.8 ± 12.5 kg; peak height velocity: 2.53 ± 1.2 yrs) participated in this double-blind, placebo-controlled, crossover designed study. Participants consumed 2 x 70 mL of BR (~12.9 mmol NO3¯; Beet It Sport®) or a nitrate-depleted placebo (PL) 2.5 hours prior to performing isometric mid-thigh pulls (IMTP) and four repeated 20-second Wingate sprints (S1-S4) interspersed with 4 minutes of rest...
March 10, 2018: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
Elham Z Movassagh, Adam D G Baxter-Jones, Saija Kontulainen, Susan Whiting, Michael Szafron, Hassan Vatanparast
BACKGROUND: The amount of bone accrued during adolescence is an important determinant of later osteoporosis risk. Little is known about the influence of dietary patterns (DPs) on the bone during adolescence and their potential long-term implications into adulthood. We examined the role of adolescent DPs on adolescent and young adult bone and change in DPs from adolescence to young adulthood. METHODS: We recruited participants from the Saskatchewan Pediatric Bone Mineral Accrual Study (1991-2011)...
February 28, 2018: Nutrition Journal
Mark De Ste Croix, Abigail Priestley, Rhodri Lloyd, Jon Oliver
PURPOSE: Fatigue negatively alters dynamic knee control, and the functional hamstring/quadriceps ratio (H/QFUNC ) plays an important role in stabilizing the joint. The aim of this study was to investigate the influence of soccer-specific exercise on H/QFUNC in under (U) 13-, U15-, and U17-year-old female soccer players. METHODS: A total of 36 female players performed concentric and eccentric actions of the hamstrings at 60°, 120°, and 180°/s before and after an age group-specific field-based soccer protocol...
February 27, 2018: Pediatric Exercise Science
Heita Goto, John G Morris, Mary E Nevill
The aim of this study was to examine the influence of biological maturity on match performance in elite youth male soccer players. The participants were 80 Premier League Academy outfield players (8-16 years old). Biological maturity was determined by calculating estimated chronological age at peak height velocity. The U9 and U10 squads played 6-a-side and the U11-U16 squads played 11-a-side inter-academy matches. All matches were analyzed using a 1 Hz Global Positioning System (SPI elite, GPSport, Australia) with squad specific speed zones which were calculated based on 5 m flying sprint speed in the last 5 m of 10 m sprint test...
February 14, 2018: Journal of Strength and Conditioning Research
M R Garcia, A D Nicholson, A M Nduaguba, J O Sanders, R W Liu, D R Cooperman
Purpose: There are multiple skeletal maturity grading systems, but none of them utilizes the phalanges of the foot. To minimize radiation, it would be ideal if one could assess the skeletal maturity of a foot based on bones seen on routine foot radiographs, if guided growth is being considered as a treatment option. We developed a system that correlates changes of the appearance of the foot phalanges to peak height velocity (PHV) and the recently described calcaneal apophyseal ossification grading system...
February 1, 2018: Journal of Children's Orthopaedics
A D Nicholson, J O Sanders, R W Liu, D R Cooperman
Purpose: We investigate the thenar and plantar sesamoids as markers of skeletal maturity, and grade appearance using two scales, a binary system (absent or present), and an analogue system that relies upon judging regular changes in morphological appearance. Methods: We studied 94 healthy children (49 female and 45 male patients) between ages three and 18 years who had approximately 700 serially acquired sets of radiographs and physical examinations. The children had at least annual radiographs taken of the left hand and left foot...
February 1, 2018: Journal of Children's Orthopaedics
Suziane Ungari Cayres, Fabio Santos de Lira, Han C G Kemper, Jamile Sanches Codogno, Maurício Fregonesi Barbosa, Romulo Araújo Fernandes
We analyzed the effects of 1 year of engagement in ≥ 300 min/week of organized sports on inflammatory levels and vascular structure in adolescents. The sample was composed of 89 adolescents (11.6 ± 0.7 years old [43 boys and 46 girls]), stratified according to engagement in ≥ 300 min/week of sport practice during at least 12 months of follow-up (n = 15, sport practice; n = 74, non-sport practice). Arterial thickness (carotid and femoral) was assessed by ultrasound scan, while high sensitive C-reactive protein levels were used to assess inflammatory status...
January 27, 2018: European Journal of Pediatrics
Conall F Murtagh, Thomas E Brownlee, Andrew OʼBoyle, Ryland Morgans, Barry Drust, Robert M Erskine
Murtagh, CF, Brownlee, TE, O'Boyle, A, Morgans, R, Drust, B, and Erskine, RM. Importance of speed and power in elite youth soccer depends on maturation status. J Strength Cond Res 32(2): 297-303, 2018-Maturation status is a confounding factor when identifying talent in elite youth soccer players (ESP). By comparing performance of ESP and control participants (CON) matched for maturation status, the aims of our study were to establish the importance of acceleration, sprint, horizontal-forward jump, and vertical jump capabilities for determining elite soccer playing status at different stages of maturation...
February 2018: Journal of Strength and Conditioning Research
Greg Doncaster, John Iga, Viswanath Unnithan
PURPOSE: The purpose of the study was to examine differences in measures of cardiorespiratory fitness and determinants of running economy with respect to maturity status in a group of highly trained youth soccer players. METHODS: A total of 21 highly trained youth soccer players participated in this study. On separate visits, players' peak oxygen uptake (VO2peak), running economy at 3 different speeds [8 km·h-1, 80% gaseous exchange threshold (GET), and 95% GET], and pulmonary oxygen uptake (VO2) kinetics were determined...
December 23, 2017: Pediatric Exercise Science
Jennifer L Gay, Eva V Monsma, Katie Darby Hein
PURPOSE: To assess the association between growth and maturation with weight management behaviors (WMBs) among Mexican American youth. DESIGN: A cross-sectional design was used to measure timing of growth and maturation as well as WMBs. SAMPLE: Students were recruited through physical education classes in south Texas schools. The sample included 623 participants (52.3% female; 49.8% with weight ≥85th percentile) in grades 4 through 12. Students in middle school were purposely oversampled to examine questions around timing of growth and maturation...
February 2018: American Journal of Health Promotion: AJHP
James O Sanders, Xing Qiu, Xiang Lu, Dana L Duren, Raymond W Liu, Debbie Dang, Mariano E Menendez, Sarah D Hans, David R Weber, Daniel R Cooperman
Humans are one of the few species undergoing an adolescent growth spurt. Because children enter the spurt at different ages making age a poor maturity measure, longitudinal studies are necessary to identify the growth patterns and identify commonalities in adolescent growth. The standard maturity determinant, peak height velocity (PHV) timing, is difficult to estimate in individuals due to diurnal, postural, and measurement variation. Using prospective longitudinal populations of healthy children from two North American populations, we compared the timing of the adolescent growth spurt's peak height velocity to normalized heights and hand skeletal maturity radiographs...
December 1, 2017: Scientific Reports
Mohamed Amin Selmi, Badriya Al-Haddabi, Mohamed Haj Yahmed, Radhouane Haj Sassi
The purpose of this study is to examine the relationship between repeated-sprint sets (RSS) performance indices and anaerobic speed reserve (ASR) in young soccer players of different maturity status. One hundred and seventy nine young male soccer players (11.1 to 17.8 years) classified as pre- (n=50), circum- (n=60), or post- (n=69) peak height velocity (PHV) performed multi-stage shuttle run test (MRST) to measure maximal aerobic speed (MAS), 30-m sprint with 10-m splits to estimate maximal anaerobic speed (MAnS), and RSS test...
November 29, 2017: Journal of Strength and Conditioning Research
Yasuyoshi Mogi, Suguru Torii, Yasuo Kawakami, Toshimasa Yanai
PURPOSE: This study aimed to elucidate growth pattern of mechanical properties of the Achilles tendon and to examine if imbalance between growth of bone and muscle-tendon unit occurs during adolescence. METHODS: Fourteen elementary school boys, 30 junior high school boys, 20 high school boys and 15 male adults participated in this study. Based on estimated age at peak height velocity (PHV), junior high school boys were separated into two groups (before or after PHV)...
January 2018: European Journal of Applied Physiology
Jordan Yardain Amar, Kimberly Borden, Elizabeth Watson, Talin Arslanian
Isolated Growth Hormone Deficiency (IGHD) is a rare cause of short stature, treated with the standard regimen of subcutaneous synthetic growth hormone (GH). Patients typically achieve a maximum height velocity in the first year of treatment, which then tapers shortly after treatment is stopped. We report a case of a 9-year-old male who presented with short stature (<3rd percentile for age and race). Basal hormone levels showed undetectable serum IGF1. Skeletal wrist age was consistent with chronologic age...
2017: Endocrinology, Diabetes & Metabolism Case Reports
André O Werneck, Danilo R Silva, Paul J Collings, Rômulo A Fernandes, Enio R V Ronque, Manuel J Coelho-E-Silva, Luís B Sardinha, Edilson S Cyrino
OBJECTIVE: To test the biocultural model through direct and indirect associations between biological maturation, adiposity, cardiorespiratory fitness, feelings of sadness, social relationships, and physical activity in adolescents. METHODS: This was a cross-sectional study conducted with 1,152 Brazilian adolescents aged between 10 and 17 years. Somatic maturation was estimated through Mirwald's method (peak height velocity). Physical activity was assessed through Baecke questionnaire (occupational, leisure, and sport contexts)...
November 13, 2017: Jornal de Pediatria
Andrew J Simpkin, Adrian Sayers, Mark S Gilthorpe, Jon Heron, Kate Tilling
BACKGROUND: Controlling for maturational status and timing is crucial in lifecourse epidemiology. One popular non-invasive measure of maturity is the age at peak height velocity (PHV). There are several ways to estimate age at PHV, but it is unclear which of these to use in practice. AIM: To find the optimal approach for estimating age at PHV. SUBJECTS AND METHODS: Methods included the Preece & Baines non-linear growth model, multi-level models with fractional polynomials, SuperImposition by Translation And Rotation (SITAR) and functional data analysis...
December 2017: Annals of Human Biology
Rossana C Nogueira, Benjamin K Weeks, Belinda Beck
PURPOSE: To determine the 12-month maintenance of a 9-month, thrice-weekly, 10-minute high-intensity exercise program, delivered in schools, on bone and other health-related performance variables in prepubertal children. METHODS: All participants (N = 311) of the CAPO kids trial (testing times T1-T2) were contacted to undergo retesting (T3) of all original measures-including weight, standing and sitting height, calcaneal broadband ultrasound attenuation (Achilles, GE), and stiffness index (Achilles, GE)-waist circumference, resting heart rate, blood pressure, vertical jump, and aerobic capacity...
November 1, 2017: Pediatric Exercise Science
M Rodriguez-Ayllon, C Cadenas-Sanchez, I Esteban-Cornejo, J H Migueles, J Mora-Gonzalez, P Henriksson, M Martín-Matillas, A Mena-Molina, P Molina-García, F Estévez-López, G M Enriquez, J C Perales, J R Ruiz, A Catena, F B Ortega
OBJECTIVES: To examine the associations of physical fitness (i.e. cardiorespiratory fitness, muscular strength, and speed/agility) with psychological distress and psychological well-being in overweight/obese pre-adolescent children. DESIGN: 110 overweight/obese children (10.0±1.1years old, 61 boys) from the ActiveBrains project ( participated in this cross-sectional study. METHODS: Physical fitness was evaluated by the ALPHA battery test...
October 4, 2017: Journal of Science and Medicine in Sport
Susan W Yeargin, Payton Kingsley, Jim M Mensch, Jason P Mihalik, Eva V Monsma
CONTEXT: There is a paucity of head impact biomechanics research focusing on youth athletes. Little is known about how youth subconcussive head impact tolerances are related to physical size and maturation. OBJECTIVE: To examine the effects of age, anthropometric and maturational status variability on head impact biomechanics. DESIGN: Cross-sectional. SETTING: Outdoor youth football facilities in South Carolina. PARTICIPANTS: Thirty-four male recreational youth football players, 8 to 13yrs...
October 3, 2017: International Journal of Psychophysiology
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