Adam Dominic George Baxter-Jones

University of Saskatchewan | U of S · College of Kinesiology

Background Previously, we developed a mathematical model capable of predicting pubertal development (PD) through seven anthropometric variables, with an accuracy of 75%. We believe that it is possible to develop a similar model that uses fewer anthropometric measurements and provides greater precision. Objective Develop a mathematical model capabl...

Purpose Although spurts in physical capacities during adolescence are well-known, little is known about the existence of such spurts in sport-specific skill development, especially during the period of rapid growth in stature. Our aims were to examine the timing, intensity, and sequence of basketball-specific skill spurts aligned with biological [y...

INTRODUCTION: Young athletes of the same chronological age differ in their physical growth, biological maturation, motor performance, and training history. These differences make it difficult for coaches to select athletes. In this study, we investigate whether training experience, biological maturation, physical performance, and technical skills a...

Success in speed swimming depends on the efficiency of the anaerobic system for the production of cellular energy, especially during muscle power production. In the adolescent athletes much is unknown with regards to the relationships between relative power of upper and lower limbs with speed swimming performance. The aim the present study was to i...

Increasing children’s physical activity engagement has short- and long-term health benefits. Developing physical competence is a key component of children’s engagement in physical activity. The purpose of our study was to assess if a 12-week home, school, and community-based physical literacy intervention improved the physical competence of childre...

The concepts of a child’s growth and maturation are central to all studies related to paediatric exercise science. It is imperative that any studies investigating responses to exercise and/or physical activity take into consideration the growth and maturity status of the participant. Distinguishing influences of physical activity and/or exercise on...

This book presents an integrated, research-driven, collection of 54 evidence-based chapters. Chapters are founded on the research and practical experience of 104 internationally renowned scientists and clinicians, from 25 countries. Each extensively referenced chapter concludes with a bulleted summary and where appropriate is cross-referenced to co...

Background It is not yet known whether the years after peak height velocity (PHV) are associated with the physiological mechanisms of muscle strength and power in Juniors rowers. Objective To identify the association between years post PHV (YPPHV) with muscle power and strength in Juniors rowers. Methods We tested 235 Brazilian rowing athletes (m...

Sports 2021 Best Paper Award

This study models children's musculoskeletal fitness (MSF) developmental trajectories and identifies individual differences related to effects of time-invariant, as well as time-varying covariates. A total of 348 Portuguese children (177 girls) from six age cohorts were followed for three years. MSF tests (handgrip strength, standing long jump and...

Background Although adolescent basketballers differ in body size, shape, and composition, less is known about how these factors interact during physical development. Aim We used ontogenetic allometry to identify the optimal body size and shape characteristics associated with physical performance in adolescent basketball players, and investigated t...

O presente estudo pesquisou o poder discriminante da bateria de testes Talent Opportunity Program (TOPS) em ginastas brasileiras de elite e não-elite de três categorias competitivas: pré-infantil, infantil e juvenil. A amostra compreende 234 ginastas (67 elite e 170 não-elite) de 9 a 15 anos, provenientes de 26 clubes. Foram obtidas informações ant...

Visual abstract of the main research findings "Reliability of biological maturation analyses performed by equations predicting skeletal age and peak height velocity with hand and wrist X-ray results", the complete text can be read at: https://doi.org/10.1002/ajhb.23775

Purpose To describe longitudinal trends in children’s moderate-to-vigorous physical activity (MVPA), and to investigate associations with individual, familial and school characteristics. Methods A sample of 341 5-10 years old Portuguese children (173 girls) from 6 age-cohorts was followed over three years using a mixed-longitudinal design. Phy...

Background Hand-wrist radiography is the gold standard for the assessment of skeletal age (SA) and the assignment of biological maturation (BM) status. However, its practical use in the field is questioned, prompting the development of anthropometric equations to estimate BM. However, there is no consensus on the reliability of these equations in r...

We aim to (1) estimate age of attainment of the peak mid-growth spurt in stature (age-at-peak MGS) in pre-adolescent boys and girls; (2) identify the timing, intensity, and sequences of physical fitness (PF) spurts aligned by the age-at-peak MGS; and (3) identify any sex differences in PF spurts aligned by age-at-peak MGS. The sample included 180 P...

Background Longitudinal data analysis can improve our understanding of the influences on health trajectories across the life-course. There are a variety of statistical models which can be used, and their fitting and interpretation can be complex, particularly where there is a nonlinear trajectory. Our aim was to provide an accessible guide along wi...

In this chapter, the physical attributes and normal patterns of growth of young children and adolescents are discussed. Variability in the tempo and timing of normal growth and development is addressed, and its relevance to participation in youth sport is discussed. This is pertinent in today’s context of sport specialization at relatively young ag...

In the context of cognitive characteristics, it is not yet known which ones would be discriminating for the sports performance of athletes from different sports, as well as, it is not known which cognitive characteristics need to be considered to discriminate an athlete who is more likely to be successful in sports. Thus, it is necessary to underst...

Background The literature identifies several factors that are associated with lower limb performance (LLP). However, there is little consensus on which factors have the major associations with LLP. Objective Examine, analyze and summarize the scientific evidence on the factors associated with the performance of LLP in children and adolescents of b...

Abstract Background: The literature identifies several factors that are associated with lower limb performance (LLP). However, there is little consensus on which factors have the major associations with LLP. Objective: Examine, analyze and summarize the scientific evidence on the factors associated with the performance of LLP in children and adoles...

Although technical skills are a prerequisite for success in basketball, little is known about how they develop over time. In this study, we model the trajectories of technical skill development in young basketball players and investigate the effects of training experience, training volume, body composition, maturity status, physical performance, an...

Context: Girls' and boys' growth patterns differ in timing and tempo, and they have different lifestyles with regards to diet and physical activity. These factors have all been linked with bone mineral accrual. Objective: To identify the associations of boys' and girls' growth, maturation, and lifestyle choices relating to parameters of bone geo...

This is an editorial for an upcoming issue of Science and Medicine in Football, critically evaluating the use of non-invasive estimations of somatic maturity such as maturity offset and predicted adult stature based estimations. It provides guidelines for researchers and practitioners who estimate somatic maturity in sport settings.

This study investigated the associations between biological and environmental factors and gross-motor coordination (GMC) in Peruvian children and adolescents. The sample comprised 7401 boys and girls, aged 6–14 years, recruited from three geographical regions: sea-level, Amazon and high-altitude. Biological variables included age, sex, height, BMI,...

Background The biological maturation (BM) analyzed by peak height velocity (PHV) and bone age (BA), and lean body mass has been associated with the strength and muscle power of young athletes. However, the ability of BM (PHV and BA) and LM markers to predict muscle strength and power in young athletes remains uncertain. Objective The Aim was deter...

Abstract Background The biological maturation (BM) analyzed by peak height velocity (PHV) and bone age (BA), and lean body mass has been associated with the strength and muscle power of young athletes. However, the ability of BM (PHV and BA) and LM markers to predict muscle strength and power in young athletes remains uncertain. Objective The Aim...

Background Physical activity (PA) patterns in children with juvenile idiopathic arthritis (JIA) over time are not well described. The aim of this study was to describe associations of physical activity (PA) with disease activity, function, pain, and psychosocial stress in the 2 years following diagnosis in an inception cohort of children with juven...

A number of studies have demonstrated that patients with autoimmune disease have lower levels of vitamin D prompting speculation that vitamin D might suppress inflammation and immune responses in children with Juvenile Idiopathic Arthritis (JIA). The objective of this study was to compare vitamin D levels in children with JIA at disease onset with...

Longitudinal data analysis can improve our understanding of the influences on health trajectories across the life-course. There are a variety of statistical models which can be used, and their fitting and interpretation can be complex, particularly where there is a nonlinear trajectory. This paper provides a guide to describing nonlinear growth tra...

In this paper, we outline a systematic testing programme developed to help identify excellence in youth basketball players. We examine the links between biological maturation and training experience with anthropometry, body composition, physical performance, technical and tactical skills from five agecohorts, and characterize, in detail, facets of...

This study investigates the interplay between individual and natural environments, as well as the effects of school characteristics, on Peruvian children and adolescents’ gross motor coordination (GMC) problems. The sample comprises 7401 participants (4121 girls) aged 6–14 years from three geographical regions: sea-level, Amazon and high-altitude....

This study aimed to (1) estimate age‐at‐mid‐growth spurt (age‐at‐MGS) in Portuguese boys from two different regions—the Azores islands and Viana do Castelo, and (2) identify spurts in a variety of physical fitness (PF) components aligned by age‐at‐MGS in the two samples. A total of 176 (Azores, n = 91; Viana do Castelo, n = 85) boys aged 6 years ol...

The aim of this systematic review was to identify and synthesize the available information regarding longitudinal data addressing young soccer players’ motor performance changes. Following the Preferred Reporting Items for Systematic and Meta-analyses (PRISMA) statement, literature searches were performed in three databases: PubMed, ISI Web of Scie...

This study investigated developmental stability, or tracking, in the development of technical skills in youth male basketball players and retrospectively profiled stable and unstable tracking patterns over time. A total of 97 basketball players were tracked bi-annually over 3 consecutive years. Players were divided into two age-categories according...

Youth soccer performance is multifaceted, includes physical growth, biological maturation, and physical fitness, and is linked to the sporting environment to which the players are exposed. We aim to describe age-related associations in body physique, body composition, physical performance technical and tactical skills, psychological and club charac...

Background: Physical activity (PA) patterns in children with juvenile idiopathic arthritis (JIA) over time are not well described. The aim of this study was to describe associations of physical activity (PA) with disease activity, function, pain, and psychosocial stress in the two years following diagnosis in an inception cohort of children with ju...

Although successful performance in basketball requires high levels of muscular strength during adolescence, its development is confounded by the effects of normal growth. We examine the timing, intensity and sequence of muscular strength according to biological age (years from peak height velocity (PHV)) and hypothesize that young basketball player...

Context: Across adolescence, there is a notable decline in physical activity in boys and girls. Maturational timing may be a risk factor for disengagement from physical activity and increased sedentary behaviours during adolescence. Objective: This systematic review aimed to summarise literature that examined the relationship between maturationa...

Background: Data relating physical performance to the timing of the adolescent growth spurt are limited. Aim: This study identifies: (i) age-at-peak height velocity (APHV), (ii) physical performance spurt patterns aligned to APHV; and (iii) cross-cultural and time patterns in Canadian, Brazilian and Portuguese boys. Subjects and methods: A total o...

This study aimed to identify the interactional relationships between maturation (biological age (BA)) and lean mass on strength development in young athletes from different sports. Using a cross-sectional study design, a sample of 64 young athletes (rowers, swimmers, jiujitsu , volleyball, soccer and tennis players) of both sexes (13.6 ± 1.17 years...

Background During adolescence, deselection from sport occurs during team try-outs when month of birth, stage of growth and maturation may influence selection. Aim The purpose of this study was to identify differences in growth and maturity related factors between those selected and deselected in youth sports teams and identify short-term associatio...

Growth and physical performance scores were studied around three years of attainment of peak height velocity (PHV). We aimed to estimate the age at peak velocity, or at peak rate, in physical performance tasks, and sex-differences when aligned by biological age. A total of 131 boys and 123 girls, 8 to 14 years of age were recruited from the Cariri...

This study (1) investigated the effects of age, maturity status, anthropometrics, and years of training on 11–14-year-old male basketball players’ physical performance and technical skills development, and (2) estimated the contribution of maturity status and training years on players’ physical and technical performances. The sample consisted of 15...

This study modelled children's gross motor coordination, investigated sex-differences and identified the effects of fixed and dynamic correlates on motor coordination development. A total of 344 Portuguese children (170 girls), from 6 age cohorts (5 to 9 years of age), were followed consecutively for three years (age range 5 to 11 years) using a mi...

INTRODUCTION: Youth sports excellence is the result of complex interactions of genetic material and environmental factors. Although such interactions are accepted as determinants of players’ development, apparently no coherent research agenda has integrated young players’ skills and aptitudes within their family support systems, coaches’ levels of...

INTRODUCTION Performance in young soccer players is multidimensional. Physiological development, technical, and tactical skills, training experience all play important roles in game performance. A longitudinal design and appropriate analytical approach will provide valuable insights into the roles of growth, maturation and the environments on socce...

In the early 1900s it was thought that exercise directly stimulated growth; however, by the end of the century it was suggested that young athletes were selected based on inherited physical attributes that enhanced performance success. In this paper, the physical attributes and normal patterns of growth of young athletes, both competitive and recre...

INTRODUCTION: High performance basketball requires, even during adolescence, exceptional physical and physiological attributes (1). Top-level technical skills (TS) are very important in identifying excellence in youth players (2). It is well-known that age, sex and competitive level differences are amplified by inter-individual differences related...

INTRODUCTION: Previous research has shown that non-dominance of feet is an important factor in a soccer players´ expertise and should be developed from early ages. This type of training is performed in decontextualized conditions or in isolated drill settings which raise issues related to its efficiency. Therefore, this study aimed to investigate w...

Objective: This study examined trajectories of trunk fat mass (FM) accrual during emerging adulthood of individuals categorized, at 36 years of age, as having higher compared with lower scores of (1) metabolic risk and (2) blood pressure risk. Methods: Fifty-five individuals from the Saskatchewan Pediatric Bone Mineral Accrual Study (1991-2017)...

The syndrome metabolic (MetS) risk factors, adiposity and physical activity (PA) levels have a multifactorial aetiology, comprising genetic and non-genetic factors. Notwithstanding the consistent findings about their aetiology, biological and behavioural traits do not explain the total variation and the dramatic increase of metabolic disorders and...

The aim of this research was to investigate individual and club-level variables that explain individual differences in gymnasts´ motor performance (MP). The sample was comprised of 249 female gymnasts (68 elite; 181 non-elite), aged between 9 and 20 years, split into four age categories: 9-10 years (n=98); 11-12 years (n=72); 13-15 years (n=64), an...

Objectives The aims of this study were (1) to identify the timing of the mid‐growth spurt (MGS) in stature in children and (2) to identify gross motor coordination (GMC) spurts when aligned by the age of attainment of the MGS (aMGS). Methods Stature, weight, and GMC were measured in 245 Portuguese children followed annually from 6 to 10 years. GMC...

This study investigated the roles of growth, maturation, physical fitness, and technical skills on selection onto an under-14 years basketball team. The sample consisted of 150 male players, aged 13.3 ± 0.7 years, divided into selected (SE—top players chosen by coaching staff to form an elite regional team) and non-selected (NSE—remaining players)...

Dietary Reference Intakes (DRIs) for calcium include the Estimated Average Requirement (EAR) and the Recommended Daily Allowance (RDA). These are estimates of the mean and the mean plus two standard deviations of the distribution of requirements for a particular subpopulation defined by sex and age. The distribution is assumed to be normal with a s...

Background: The prevalence of overweight and obesity doubles between adolescence and young adulthood. However, the exact age, and appropriate metric to use, to identify when overweight develops is still debated. Aim: To examine the age of onset of overweight by sex and four metrics: body mass index (BMI), fat mass (%FM), waist circumference (WC) an...

Background: There is a renewed interest in longitudinal studies which link children’s growth, motor and cognition development. This is important for both educational outcomes and identification of children who are at risk. Aim: To identify cross-sectional sex-differences. Subjects and methods: In total, 1166 Portuguese children, aged 4–11 years, we...

Resumo O estudo aborda procedimentos adotados por 40 treinadores na detecção e seleção de ginastas e caracteriza clubes brasileiros que têm programas de seleção (PS). Em 70% dos casos o treinador é responsável pela tomada de decisão na detecção; 90% usam testes motores (técnico‐específicos, velocidade, força e flexibilidade). O método misto é o mai...

The amount of bone gained during childhood and adolescence impacts greatly on lifetime skeletal health. The purpose of this review is to summarize current evidence of the effects of gymnastics activities on bone mineral accrual during growth and to describe possible factors that influence bone mineral gains. The PubMed and SportDiscus databases wer...

Abstract 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 an...

Purpose The aim of this study was to investigate whether adolescent growth trajectories of aerobic fitness and adiposity were associated with mid-adulthood cardiometabolic risk (CMR). Methods Participants were drawn from the Saskatchewan Growth and Development Study (1963–1973). Adolescent growth trajectories for maximal aerobic capacity (absolute...

Objectives: Emerging adulthood, a potential critical period, is an understudied period of fat mass accrual. The aim of this study was to describe patterns of fat mass accrual, and weight status, from adolescence, through emerging adulthood, into young adulthood. Methods: One-hundred-eighteen participants (59 male) were measured repeatedly for 20...

Dietary patterns established during adolescence might play a role in adulthood disease. We examined the stability of dietary patterns (DPs) from childhood through adolescence and into young adulthood (from age 8 to 34 years). Data from 130 participants (53 females) of Saskatchewan Pediatric Bone Mineral Accrual Study (aged 8-15 years, at baseline)...

It has been suggested that successful young gymnasts are a highly select group in terms of the physique. This review summarizes the available literature on elite female gymnasts’ anthropometric characteristics, somatotype, body composition and biological maturation. The main aims were to identify: (i) a common physique and (ii) the differences, if...

Purpose: Premenarcheal female gymnasts have been consistently found to have greater bone mass and structural advantages. However, little is known about whether these structural advantages are maintained after the loading stimulus is removed. Therefore, the purpose of this study was to investigate structural properties at the hip after long term re...