A comparison of multidimensional qualities discriminant of selection in elite adolescent Australian basketball athletes.

PURPOSE: The aims of this study were to (1) quantify the multidimensional attributes of male and female basketball athletes under 16 years of age (U16) and under 18 years of age (U18), and (2) identify attributes that distinguish selection into a talent pathway according to sex and age group. METHODS: 67 male and 71 female athletes competing in U16 and U18 selection trials for a state based Australian basketball talent pathway completed a multidimensional testing battery. The test battery consisted of anthropometric, physical (20- linear sprint, countermovement jump height, Yo-Yo Intermittent Recovery Test Level 2), technical (Basketball Jump Shooting Accuracy Test), tactical (video decision making), and psychological (Sports Orientation Questionnaire, Psychological Performance Inventory-Alternative) assessments. Mean differences and independent t-tests were used to assess comparative differences between selected and non-selected athletes within each age and sex cohort. Stepwise discriminant analyses were used to identify attributes that were the strongest discriminators of selection in each group (male U16, male U18, female U16, and female U18). RESULTS: The discrimminant models showed for male U16 athletes smaller height (ES = -0.18) and greater shooting accuracy (ES = 0.52) was most discriminant of selection. Results were largely homogenous for male U18 athletes with lower visualisation score (ES = -0.62) most discriminant of selection. In female cohorts, faster 20-m sprint time (ES = -0.66) and taller height (ES = 0.58) was most discriminant of selection in U16 athletes while greater shooting accuracy (ES = 0.67), countermovement jump height (ES = 1.04), and height (ES = 0.65) was most discriminant of selection in U18 athletes. CONCLUSIONS: These results emphasise the differing selection priorities within adolescent basketball cohorts according to sex and age group. The testing of anthropometric, physical and technical attributes may hold particular utility in adolescent female basketball given their identified importance to selection across U16 and U18 cohorts.

Self-Report Motor Competence in Adolescents Aged 12-18 Years in Regional and Rural Victoria (Australia).

Background: Poor motor skills are an increasing issue for adolescents in our local communities. In regional Victoria, almost 20% of children starting school in 2018 were considered at risk or developmentally vulnerable in the domain of physical health and wellbeing. Purpose: The aim of the current study was to examine factors (how adolescents perceive their fine and gross motor skills, activities of daily living, comparison to peers) of motor competence that may be important to adolescents in regional Victoria, Australia, using the Adolescent Motor Competence Questionnaire (AMCQ). Methods: A sample of 183 Australian adolescents ([138 females (Mage = 15.59 years, SD = 1.56); 45 males, (Mage = 15.82 years, SD = 1.95); 12-18 years old] completed the AMCQ. Results: The mean AMCQ score was 87.86 (SD = 7.55), with no significant difference between males (M = 89.67 SD = 7.29) and females [M = 87.28 SD = 7.56; t (181 = 1.86 p =.065)]. A Principal Component Analysis (PCA), extracted five factors (Eiqenvalue of 1.389) explaining 43.46% of variance, representing, Ball Skills and Kinesthesis; Activities of Daily Living; Fine Motor and Gross Motor; Proprioception and Exteroception; Public Performance. Conclusion: The results highlight key factors important in describing an adolescent's motor competence within regional Victoria. With physical health a priority in local communities, understanding these factors is an important first, that which may inform development of physical activity interventions for adolescents.

Impact of a multimodal exercise program on tibial bone health in adolescents with Development Coordination Disorder: an examination of feasibility and potential efficacy.

OBJECTIVES: Developmental coordination disorder (DCD) compromises bone health purportedly due to lower levels of physical activity. The potential of an exercise intervention to improve bone health parameters in adolescents with DCD has not previously been studied. This study thus aimed to determine the impact of a multimodal exercise intervention on bone health in this population at-risk of secondary osteoporosis. METHODS: Twenty-eight adolescents (17 male, 11 female) aged between 12-17 years (Mage=14.1) with DCD participated in a twice weekly, 13-week generalised multimodal exercise intervention. Peripheral quantitative computed tomography scans of the tibia (4% and 66%) were performed over a six month period. Generalised estimating equations were used to examine the impact of fitness measures on bone parameters over time. RESULTS: An overall improvement trend was observed for bone health, with significant increases at the 66% tibial site for bone mass (4.12% increase, dcohen=0.23, p=0.010) and cortical area (5.42% increase, η2 =12.09, p=0.014). Lower body fitness measures were significantly associated with improvements in bone health parameters, tempered by the degree of motor impairment. CONCLUSION: A multimodal exercise intervention may be effective in improving bone health of adolescents with DCD. Given the impact of motor impairments, gains may be greater over an extended period of study.

Does level of motor competence affect the associations between identity health and self-perceptions in adolescents?

BACKGROUND: Adolescence is a particularly important time for the development of self-perceptions and identity as many environmental and personal factors are influential. One relatively unexplored factor is level of motor competence. AIM: To examine the relationship between identity health and self-perceptions in male and female adolescents with low motor competence (LMC) compared to typically developing (TD) adolescents. METHOD: Adolescents (N = 160, 64.4% males, Mage = 14.45 yrs., SD = 0.75) completed the Adolescent Motor Competence Questionnaire (AMCQ), Assessment of Identity Development in Adolescence (AIDA), and Harter's Self-Perception Profile for Adolescents (SPPA). Based on the AMCQ score, the sample was grouped into LMC and TD. Pearson's product moment correlations between the AIDA and SPPA subscales were derived for gender, competence groups, and gender x competence sub-groups. RESULTS: Overall, males had lower AIDA scores (healthier identity) than the females and significant associations with all self-perception domains. For females, only scholastic and social competence, physical appearance, behavioural conduct, close friendship and Global Self-worth (GSW) domains were significantly related to their AIDA score. The adolescents in the LMC group had higher AIDA scores (less-healthier identity) and fewer self-perception domains [scholastic competence, physical appearance, behavioural conduct, close friendships and GSW] were associated to their AIDA scores. For the TD group, all self-perception domains were significantly correlated with their AIDA scores. When grouped by gender and motor competence, the TD males had the healthiest identity scores which were strongly associated with all self-perception subdomains. For males with LMC, only scholastic competence, behavioural conduct and GSW domains were significantly related with their identity score. Females from both competence groups reported significant associations between physical appearance, close friendships, behavioural conduct, and social competence domains with their identity scores. Scholastic competence was also significantly associated with identity only for females with LMC. CONCLUSION: Positive self-perceptions across a range of domains are associated with a healthier identity, but differ according to level of motor competence and gender. For those with LMC, the self-perception subdomains unrelated to physical activity and sport, such as school-based aspects were associated with a healthier identity. These findings should guide school based interventions to provide support in these domains in order to strengthen self-worth and identity health.

Characterisation of peripheral bone mineral density in youth at risk of secondary osteoporosis - a preliminary insight.

OBJECTIVES: To describe peripheral long bone material and structural differences in youth at risk of secondary osteoporosis across disease-specific profiles. METHODS: Upper- and lower limbs of children and adolescents were scanned at 4% distal and 66% mid-shaft sites using peripheral Quantitative Computed Tomography sub-categorised as (1) increased risk of secondary osteoporosis (neuromuscular disorders; chronic diseases; endocrine diseases; inborn errors of metabolism; iatrogenic conditions), (2) low motor competence and (3) non-affected controls. RESULTS: Children with disease-specific profiles showed a range of bone deficits compared to the control group with these predominantly indicated for neuromuscular disorders, chronic diseases and low motor competence. Deficits between upper arm and lower leg long bone parameters were different for disease-specific profiles compared to the control group. Endocortical radius, muscle area, and mid-cortical ring density were not significantly different for any disease-specific profile compared to the control group for any bone sites. CONCLUSIONS: Neuromuscular disorders, chronic diseases and low motor competence have a strong correlation to bone health for appendicular bone parameters in youth, suggesting a critical mechanical loading influence which may differ specific to disease profile. As mechanical loading effects are observed in regional bone analyses, targeted exercise interventions to improve bone strength should be implemented to examine if this is effective in reducing the risk of secondary osteoporosis in youth.

Exploring the association between recent concussion, subconcussive impacts and depressive symptoms in male Australian Football players.

OBJECTIVES: To explore the association between depressive symptoms and recent head-related trauma (diagnosed concussion, subconcussive impacts) in semiprofessional male Australian Football (AF) players. METHODS: Sixty-nine semiprofessional male players from a West Australian Football League (WAFL) club participated in the study (Mage=21.81, SD=2.91 years). Depressive symptoms were measured using the Centre for Epidemiological Studies Depression Scale. Injuries and potential confounding variables (eg, pre-existing mental health condition; alcohol or drug hangovers; experiencing a stressful event) were self-reported anonymously using the WAFL Injury Report Survey. Both tools were administered every 2-weeks over the first 22-weeks of the WAFL season. Controlling for potential confounding variables and other injuries, a repeated measures generalised estimating equations model assessed the risk of clinically relevant depressive symptoms occurring, when diagnosed concussion or subconcussive impacts were experienced. RESULTS: A total of 10 concussions and 183 subconcussive impacts were reported. Players who experienced a concussion were almost nine times more likely to experience clinically relevant depressive symptoms (OR 8.88, 95% CI 2.65 to 29.77, p<0.001). Although elevated, depressive symptoms following subconcussive impacts were not statistically significant (OR 1.13, 95% CI 0.67 to 1.92, p=0.641). CONCLUSION: These findings indicate that semiprofessional AF athletes may be at risk of experiencing depressive symptoms after concussion. Severity (concussion vs subconcussive impacts) and dose (number of impacts) appear to have an important relationship with depressive symptom outcomes in this cohort and should be considered for further research and management of player welfare.

The Influence of Motor Competence on Adolescent Identity Health: A Mixed Method Study.

Our identity develops with age, and many impacting factors will determine whether it is healthy or unhealthy. A particularly fragile phase of identity development occurs during adolescence when level of motor competence may be influential, yet is rarely considered. Purpose: The purpose of this study was to examine male and female adolescent's perceptions towards their motor competence and identity development. In-depth information was also collected to understand what factors are important towards identity development during adolescence. Method: An explanatory sequential mixed methods study was used to examine the extent motor competence influenced the health of an adolescent's identity. A sample of 160 adolescents (male n = 103, female n = 57, Mage = 14.45 SD = .75) completed the Adolescent Motor Competence Questionnaire (AMCQ) and the Assessment of Identity Development in Adolescence (AIDA). The AMCQ scores were used to group the participants into high (HMC = > 83) and low (LMC = < 83) motor competence. Results: More females had less-healthy identities than males and those with LMC had less-healthy identities than those with HMC. Subsamples of 17 participants were interviewed in order to explain these results. The most at risk group, females with LMC, identified negative peer comparisons, poor social support and higher stress levels to achieve academic performance as key challenges. Conclusions. Well-designed support services for those with LMC, especially for the females should incorporate activities to develop individual competency and close friendships.

Exploring the influence of self-perceptions on the relationship between motor competence and identity in adolescents.

BACKGROUND AND AIMS: A relationship exists between an adolescent's level of motor competence and the health of their identity. As those with low motor competence (LMC) form less healthy identities, the aim of this study was to investigate if self-perceptions mediated the negative impact of LMC on identity health. METHODS: Adolescents (N = 160) completed the Adolescent Motor Competence Questionnaire (AMCQ), Assessment of Identity Development in Adolescence (AIDA) and the Self Perception Profile for Adolescence (SPPA). The mediating effect of their self-perceptions on the relationship between motor competence and identity health was examined in several ways: for the total sample, between male and females, and level of motor competence. Two motor competence groups were formed by dichotomizing their AMCQ scores (< 83 = LMC). RESULTS: There was an indirect effect of self-perceptions of social competence, physical appearance, romantic appeal, behavioural conduct, close friendships and global self-worth on the relationship between motor competence and identity health for the total sample (N = 160, 64.4% males, Mage = 14.45 SD = .75, 12 to 16 years). No indirect effects were significant for females however close friendships and global self-worth were significant for the males. When the sample was grouped for motor competence, indirect effects of social competence, athletic competence, physical appearance, behavioural conduct, and global self-worth were significant for the high motor competence (HMC) group. The only self-perception significant for the LMC group was close friendships. CONCLUSION: Self-perceptions in several domains mediated the relationship between motor competence and identity health, and these differed for level of motor competence but not gender. Those with LMC who had a higher self-perception in the close friendships domain had a healthier identity. Designing physical activity programs that focus on skill development and forming close friendships are important for adolescents with LMC.

Suboptimal bone status for adolescents with low motor competence and developmental coordination disorder-It's sex specific.

BACKGROUND: Australian adolescents with low motor competence (LMC) have higher fracture rates and poorer bone health compared to European normative data, but currently no normative data exists for Australians. AIMS: To examine whether there were bone health differences in Australian adolescents with LMC or Developmental Coordination Disorder (DCD) when compared to typically developing age-matched Australian adolescents. METHODS AND PROCEDURES: Australian adolescents aged 12-18 years with LMC/DCD (n = 39; male = 27; female = 12) and an Australian comparison sample (n = 188; boys = 101; girls = 87) undertook radial and tibial peripheral Quantitative Computed Tomography (pQCT) scans. Stress Strain Index (SSI (mm3)), Total Bone Area (TBA (mm2)), Muscle Density (MuD [mgcm3]), Muscle Area (MuA [cm2]), Subcutaneous Fat Area (ScFA [cm2]), Cortical Density (CoD [mgcm3]), Cortical Area (CoD [mm2]), cortical concentric ring volumetric densities, Functional Muscle Bone Unit Index (FMBU: (SSI/bone length)) and Robustness Index (SSI/bone length^3), group and sex differences were examined. OUTCOME AND RESULTS: The main finding was a significant sex-x-group interaction for Tibial FMBU (p = .021), Radial MuD (p = .036), and radial ScFA (p = .002). Boys with LMC/DCD had lower tibial FMBU scores, radial MuD and higher ScFA than the typically developing age-matched sample. CONCLUSION AND IMPLICATIONS: Comparisons of bone measures with Australian comparative data are similar to European findings however sex differences were found in the present study. Australian adolescent boys with LMC/DCD had less robust bones compared to their well-coordinated Australian peers, whereas there were no differences between groups for girls. These differences may be due to lower levels of habitual weight-bearing physical activity, which may be more distinct in adolescent boys with LMC/DCD compared to girls.

Time for change: Fitness and strength can be improved and sustained in adolescents with low motor competence.

BACKGROUND: There are few exercise interventions focused on adolescents with low motor competence and most interventions are short with little follow up and engagement over time. METHODS AND PROCEDURES: Fifty-eight adolescents with low motor competence (39 males, Mean Age = 13.6, SD = 1.4 years) attended an exercise clinic twice a week for each 13 week program. Two programs ran each year, and participants attended for as long as they felt progress was made or they turned 18 years of age. Performance on the Multistage Fitness Test (MSFT), Curl-ups, Grip Strength, 1RM Leg press and Chest Press, Vertical Jump and Standing Broad Jump (SBJ) were recorded pre and post each program for up to six years. Linear Mixed Modelling (LMM) determined changes in fitness measures over time whilst adjusting for gender, age and Neuromuscular Developmental Index (McCarron, 1997). RESULTS: All fitness measures increased, and specifically four of the seven fitness outcomes showed significant improvement over time (MSFT,p = 0.011; curl-ups, p < 0.001, grip strength p = 0.003, and SBJ p = 0.006). CONCLUSION: An individually tailored regular exercise program in a supportive environment can achieve exercise adherence and sustainable improvements in fitness outcomes for adolescents with low motor competence. Future research should consider the addition of a comparison LMC control group to increase understanding of the intervention effect.

Appendicular fracture epidemiology of children and adolescents: a 10-year case review in Western Australia (2005 to 2015).

Fracture incidence data of Australian children and adolescents have not been reported in the literature. A 10-year case review of fracture presentations in Western Australia is provided. Between 2005 and 2015, fracture incidence increased relative to population growth. This is concerning, and interventions are required to reverse this trend. PURPOSE: Fracture incidence in 0-16-year-olds is high and varies between countries. Boys have a 1.5:1 ratio of fracture incidence compared to girls. There are no specific data for Australia. Western Australia is a state with unique geography and population distribution having only a single tertiary paediatric hospital (Princess Margaret Hospital, PMH, in Perth) managing the majority of children and adolescents with fractures in the Emergency Department (ED). The aims of this study were to characterise fracture presentations to PMH-ED and compare the incidence to population data. METHODS: A database audit of fracture presentations between 2005 and 2015 for fracture rates with a sub-analysis for gender, fracture site and age and a comparison to Perth Metropolitan and Western Australian population data was performed. RESULTS: Analysis included 31,340 presentations. Fracture incidence, adjusted for the annual population size, increased from 0.63% in 2005 to 0.85% in 2015 (p < 0.001). The month of May reported the highest fracture rate (p < 0.001) corresponding with the start of the winter sports season. Males had a 1.5 times higher fracture incidence than females (p < 0.001), with upper limb fractures three times more common than lower limb fractures (p < 0.001). Fracture incidence increased with age until the early teenage years (15 years for males; 12 years for females) when a decline occurred. CONCLUSIONS: Increased fracture incidence in Western Australia between 2005 and 2015 identifies a concerning trend for bone health in children and adolescents. Further research is needed to identify potential lifestyle factors that impact fracture incidence translating into evidence-based strategies to reverse these trends and improve bone health.

The General Motor Ability Hypothesis: An Old Idea Revisited.

While specific motor abilities have become a popular explanation for motor performance, the older, alternate notion of a general motor ability should be revisited. Current theories lack consensus, and most motor assessment tools continue to derive a single composite score to represent motor capacity. In addition, results from elegant statistical procedures such as higher order factor analyses, cluster analyses, and Item Response Theory support a more global motor ability. We propose a contemporary model of general motor ability as a unidimensional construct that is emergent and fluid over an individual's lifespan, influenced by both biological and environmental factors. In this article, we address the implications of this model for theory, practice, assessment, and research. Based on our hypothesis and Item Response Theory, our Lifespan Motor Ability Scale can identify motor assessment tasks that are relevant and important across varied phases of lifespan development.

Please Don't Move-Evaluating Motion Artifact From Peripheral Quantitative Computed Tomography Scans Using Textural Features.

Most imaging methods, including peripheral quantitative computed tomography (pQCT), are susceptible to motion artifacts particularly in fidgety pediatric populations. Methods currently used to address motion artifact include manual screening (visual inspection) and objective assessments of the scans. However, previously reported objective methods either cannot be applied on the reconstructed image or have not been tested for distal bone sites. Therefore, the purpose of the present study was to develop and validate motion artifact classifiers to quantify motion artifact in pQCT scans. Whether textural features could provide adequate motion artifact classification performance in 2 adolescent datasets with pQCT scans from tibial and radial diaphyses and epiphyses was tested. The first dataset was split into training (66% of sample) and validation (33% of sample) datasets. Visual classification was used as the ground truth. Moderate to substantial classification performance (J48 classifier, kappa coefficients from 0.57 to 0.80) was observed in the validation dataset with the novel texture-based classifier. In applying the same classifier to the second cross-sectional dataset, a slight-to-fair (κ = 0.01-0.39) classification performance was observed. Overall, this novel textural analysis-based classifier provided a moderate-to-substantial classification of motion artifact when the classifier was specifically trained for the measurement device and population. Classification based on textural features may be used to prescreen obviously acceptable and unacceptable scans, with a subsequent human-operated visual classification of any remaining scans.

Actual competence, rather than perceived competence, is a better predictor of physical activity in children aged 6-9 years.

There is a limited understanding about the relative importance of perceived and actual competence on emergent physical activity levels in children and whether there is a difference in their development and strength between boys and girls. This study used a single-cohort, multiple age group design to monitor physical activity, actual motor competence (AMC) and perceived competence (PC) on four occasions over 18 months in 6-to 9-year-old boys and girls (N = 201). Physical activity was measured by 7-day daily step counts (pedometer) and activity diary. AMC was assessed by mastery of skill criteria for 4 motor skills; run, overhand throw, standing broad jump, and line walk. PC was measured with the Self Description Questionnaire-I. Linear Mixed Model analysis revealed that AMC, Gender and School significantly impacted physical activity levels longitudinally in these children. AMC made a greater contribution (9-30%) to physical activity levels than PC (0-5%), and at an earlier age in boys (7 years) than girls (9 years). The need to acknowledge these developing distinctions in considering emergent physical activity levels has important implications for childhood learning environments and physical activity interventions.

Development and evaluation of the psychometric properties of the Adolescent Motor Competence Questionnaire (AMCQ) for Adolescents.

BACKGROUND: There are no valid and reliable self-report measures designed to identify level of motor competence and suspected motor difficulties among 12-18year old adolescents. AIM: This paper reports the development and evaluation of a self-report questionnaire (Adolescent Motor Competence Questionnaire; AMCQ) to address this need. METHOD: The project proceeded in 3 phases; (A) item development, (B) content evaluation, and (C) examination of reliability and validity of the final questionnaire. Each phase was informed by criteria A and B in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), comments from a sample of 10 adolescents aged between 12 and 18 years with a range of movement skills, key informants and international experts. A convenience sample of 38 adolescents completed the final version of the AMCQ. The McCarron Assessment of Neuromuscular Development (MAND) was used to investigate concurrent validity. RESULTS: The final version of the AMCQ comprised 26 items scored using a 4 point Likert scale with a maximum score of 104. Analyses revealed the questionnaire has an acceptable internal consistency (0.902) and 7day test-retest reliability (0.956). A moderate positive correlation between the AMCQ and the MAND of 0.491 (p<0.002) provides some evidence of concurrent validity. CONCLUSION: The development of the AMCQ was exploratory in nature and has the potential to be a reliable and valid tool for measuring motor competence in Australian adolescents.

Exercise can improve physical self perceptions in adolescents with low motor competence.

Adolescents with low motor competence have diminished perceptions of their physical self and tend to avoid physical activities. This study examined the outcomes of an exercise intervention that focused on improving aerobic fitness, strength, and self-perceptions in the physical domain in adolescents with poor motor coordination. The sample included 35 adolescents with low motor competence, comprising boys (n = 25) and girls (n = 10) ranging in age from 13 to 17 years, who attended two sessions per week in the 13 week exercise intervention study (AMP it up). Physical self-perceptions were measured before and after the intervention using the Physical Self Perception Profile and Perceived Importance Profile. Significant improvements in perceived Physical Condition, Attractive Body and Physical Strength sub domain scores were identified between pre and post-test. Adjusting for age, gender, BMI and attendance, regression analyses revealed that Attractive Body was the strongest predictor of Physical Self Worth at pre-test, joined by Physical Condition at post-test. This exercise intervention had a positive impact on adolescent physical self-perceptions, in particular males, with improvements in those sub domains specifically related to the exercise program. Changes in specific aspects of Physical Self Worth can be facilitated by exercise interventions, after a relatively short period of time, in adolescents with poor motor coordination.