scholarly journals Testing the Functional Model of Bone Development: Direct and Mediating Role of Muscle Strength on Bone Properties in Growing Youth

2021 ◽  
Vol 18 (6) ◽  
pp. 3154
Author(s):  
Izabella A. Ludwa ◽  
Kevin Mongeon ◽  
Malcolm Sanderson ◽  
Luis Gracia Marco ◽  
Panagiota Klentrou
Keyword(s):  
Physical Activity ◽  
Muscle Strength ◽  
Indirect Effect ◽  
Bone Development ◽  
Functional Model ◽  
Bone Age ◽  
Height Velocity ◽  
Equation Modeling ◽  
Direct Impact ◽  
Bone Properties

This study examines the functional model of bone development in peri-pubertal boys and girls. Specifically, we implemented a mixed-longitudinal design and hierarchical structural models to provide experimental evidence in support of the conceptual functional model of bone development, postulating that the primary mechanical stimulus of bone strength development is muscle force. To this end, we measured radial and tibial bone properties (speed of sound, SOS), isometric grip and knee extensors strength, bone resorption (urinary NTX concentration), body mass index (BMI), somatic maturity (years from peak height velocity) and skeletal maturity (bone age) in 180 children aged 8–16 years. Measurements were repeated 2–4 times over a period of 3 years. The multilevel structural equation modeling of 406 participant-session observations revealed similar results for radial and tibial SOS. Muscle strength (i.e., grip strength for the radial and knee extension for tibial model) and NTX have a significant direct effect on bone SOS (β = 0.29 and −0.18, respectively). Somatic maturity had a direct impact on muscle strength (β = 0.24) and both a direct and indirect effect on bone SOS (total effect, β = 0.30). Physical activity and BMI also had a significant direct impact on bone properties, (β = 0.06 and −0.18, respectively), and an additional significant indirect effect through muscle strength (β = 0.01 and 0.05, respectively) with small differences per bone site and sex. Muscle strength fully mediated the impact of bone age (β = 0.14) while there was no significant effect of energy intake on either muscle strength or bone SOS. In conclusion, our results support the functional model of bone development in that muscle strength and bone metabolism directly affect bone development while the contribution of maturity, physical activity, and other modulators such as BMI, on bone development is additionally modulated through their effect on muscle strength.

scholarly journals Physical Activity–Related Injury Profile in Children and Adolescents According to Their Age, Maturation, and Level of Sports Participation

2017 ◽  
Vol 9 (2) ◽  
pp. 118-125 ◽  
Author(s):  
Lara Costa e Silva ◽  
Maria Isabel Fragoso ◽  
Júlia Teles
Keyword(s):  
Physical Activity ◽  
Injury Risk ◽  
Injury Rate ◽  
Sports Participation ◽  
Bone Age ◽  
Peak Height ◽  
Height Velocity ◽  
Peak Height Velocity ◽  
Biological Maturation ◽  
Early Maturing

Background: Physical activity (PA) is beneficial, enhancing healthy development. However, one-third of school-age children practicing sports regularly suffer from an injury. These injuries are associated with sex, chronological age, and PA level. Purpose: To identify the importance of age, PA level, and maturity as predictors of injury in Portuguese youth. Study Design: Descriptive epidemiological study. Level of Evidence: Level 3. Methods: Information about injury and PA level was assessed via 2 questionnaires (LESADO RAPIL II) from 647 subjects aged 10 to 17 years. Maturity offset according to Mirwald (time before or after peak height velocity) and Tanner-Whitehouse III bone age estimates were used to evaluate maturation. Binary logistic regression and gamma regression were used to determine significant predictors of injury and injury rate. Results: Injury occurrence was higher for both sexes in recreational, school, and federated athletes (athletes engaged in sports that are regulated by their respective federations, with formal competition). These injuries also increased with age in boys and in the higher maturity offset group in girls. Injury rate was higher for both sexes in the no sports participation group. Early-maturing girls, with higher bone age and lower maturity offset, showed higher injury rate. Conclusion: Injuries in Portuguese youth were related to PA level, age, and biological maturation. Recreational, school, and federated athletes had more injury ocurrences while subjects with no sports participation had higher injury risk. Older subjects had more injuries. Early-maturing girls that had just passed peak height velocity may be particularly vulnerable to risk of sports injury because of the growing process. Clinical Relevance: Increased knowledge about injury with specific PA exposure data is important to an overall risk management strategy. This study has deepened the association between injury and biological maturation variables.

scholarly journals Mechanical, biochemical, and dietary determinants of the functional model of bone development of the radius in children and adolescents

2017 ◽  
Vol 42 (7) ◽  
pp. 780-787
Author(s):  
Izabella A. Ludwa ◽  
Bareket Falk ◽  
Wendy E. Ward ◽  
Kimberley L. Gammage ◽  
Panagiota Klentrou
Keyword(s):  
Bone Resorption ◽  
Grip Strength ◽  
Calcium Intake ◽  
Functional Model ◽  
Dietary Factors ◽  
Height Velocity ◽  
Peak Height Velocity ◽  
Pubertal Stage ◽  
Amino Terminal ◽  
Bone Properties

This study examined the degree to which various mechanical, biochemical, and dietary factors are related to nonweight bearing bone properties in 172 healthy peri-pubertal children (age, 11.7 ± 2.0 years). Dominant radial speed of sound (rSOS) was measured by transaxial quantitative ultrasound at distal radius. Potential modulating factors included somatic maturity offset (years from age of peak height velocity), grip strength, forearm lean cross-sectional area (CSA), physical activity, nutritional intake, and amino-terminal cross-linking propeptide (NTx), reflecting bone resorption. In a hierarchical regression, grip strength adjusted for CSA was the second most important predictor of rSOS after the maturity offset (β = 0.22 and β = 0.33, respectively; R2 = 0.16). When relative grip strength was added to the model the contribution of sex was no longer significant. Calcium intake was a significant predictor of rSOS only after NTx was accounted for in the model (β = 0.17, R2 = 0.21). This may suggest that calcium’s effects on the muscle-bone unit may be modulated through bone resorption. In the final model, relative grip strength together with maturity offset, dietary calcium, and NTx explained up to 21% of the variance in rSOS in this cohort of children. Therefore, during the peri-pubertal stage, size-adjusted forearm muscle strength is related to radial bone strength after controlling for maturity, with calcium intake having a potential indirect association through NTx.

scholarly journals Lean mass and biological maturation as predictors of muscle power and strength performance in young athletes

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254552
Author(s):  
Paulo Francisco de Almeida-Neto ◽  
Rafaela Catherine da Silva Cunha de Medeiros ◽  
Dihogo Gama de Matos ◽  
Adam D. G. Baxter-Jones ◽  
Felipe J. Aidar ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Muscle Power ◽  
Bone Age ◽  
Lower Limbs ◽  
Height Velocity ◽  
Upper Limbs ◽  
Young Athletes ◽  
Adolescent Athletes ◽  
Network Analyses ◽  
Biological Maturation

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 determine the predicting power of BM markers (PHV and BA) and LM in relation to muscle power of upper and lower limbs and muscle strength of upper limbs in adolescent athletes at puberty. Methods Ninety-two adolescent athletes (both sexes; age 12.4 ± 1.02 years) were assessed for body composition by dual-energy X-ray absorptiometry (DXA). Power of upper limbs (ULP), force handgrip (HG), vertical jump (VJ) and countermovement jump (CMJ) were recorded. BM was predicted by mathematical models to estimate PHV and BA. Multilayer artificial neural network analyses (MLP’s) were used to determine the power of prediction of LM, PHV and BA on muscle power and strength of upper- and lower-limbs of the athletes. Results LM, BA and PHV were associated with HG (r>0.74, p<0.05) and ULS (r>0.60, p<0.05) in both sexes. In both sexes BA was associated with VJ (r>0.55, p<0.05) and CMJ (r>0.53, p<0.05). LM indicated associations (r>0.60, p<0.05) with BA and with PHV (r<0.83, p<0.05) in both sexes. MLP’s analysis revealed that the LM provides > 72% of probability to predict the muscle power of upper- and lower-limbs, and the strength of the upper limbs; whereas PHV provides > 43% and bone age >64% in both female and male adolescent athletes. Conclusion We identified that, like PHV and BA, LM is a strong predictor of low cost of both upper limbs muscle strength and upper and lower limbs power in adolescent athletes.

Evaluating the Youth Physical Activity Promotion Model Among Portuguese Elementary Schoolchildren

2013 ◽  
Vol 10 (8) ◽  
pp. 1159-1165 ◽  
Author(s):  
Ana C. Seabra ◽  
José Maia ◽  
André F. Seabra ◽  
Greg Welk ◽  
Robert Brustad ◽  
...  
Keyword(s):  
Physical Activity ◽  
Public Schools ◽  
Indirect Effect ◽  
Structural Equation ◽  
Parental Influence ◽  
Physical Activity Promotion ◽  
Equation Modeling ◽  
Physical Competence ◽  
Activity Promotion ◽  
Youth Physical Activity

Background:The Youth Physical Activity Promotion (YPAP) model provides an integrated approach to understanding the predisposing, enabling, and reinforcing factors influencing physical activity (PA) behavior. The purpose of this study was to evaluate an adapted version of the YPAP model for explaining PA among Portuguese schoolchildren.Methods:A random cross-sectional sample of 683 children (8–10 years of age) attending elementary public schools in the north of Portugal completed a detailed survey assessing attraction to PA, perceived physical competence, parental influences and leisure time PA. Structural equation modeling techniques were conducted (EQS6.1).Results:Attraction to PA was directly associated with children’s PA participation (β = 0.271, P < .05). Perceived physical competence imposed an indirect effect on children’s PA through children’s attraction to PA (β = 0.253, P < .05). Parental influence had an indirect effect on children’s PA through perceived physical competence and attraction to PA (β = 0.318 and 0.662, respectively, P < .05). Perceived physical competence and parental influence were not directly associated with children’s PA (β = 0.069 and 0.180, respectively, P > .05).Conclusions:The adapted version of YPAP model was useful in explaining PA participation in elementary Portuguese schoolchildren. Intervention programs intended to enhance attraction to PA, perceived physical competence and favorable parental influence should be developed to promote children’s PA participation.

Does Gender Moderate the Direct and Indirect Relationships Between Different Sources of Social Support and Adolescents’ Physical Activity?

2016 ◽  
Vol 13 (8) ◽  
pp. 874-881 ◽  
Author(s):  
Han Chen ◽  
Jun Dai
Keyword(s):  
Physical Activity ◽  
Social Support ◽  
Family Support ◽  
Peer Support ◽  
Indirect Effect ◽  
Structural Equation ◽  
Cognitive Theory ◽  
Short Form ◽  
Mediating Effect ◽  
Equation Modeling

Background:Using the social cognitive theory, this study aims to examine how gender moderates the direct and indirect relationships of various sources of social support on Chinese adolescents’ physical activity (PA).Methods:A cross-sectional study was conducted. The final data includes 396 students (55.8% are boys) who were randomly selected from 2 middle schools and 4 high schools in Fuzhou city located in southeast China. Family support, peer support, and self-efficacy (SE) were measured using validated questionnaires. Participants’ PA was assessed using the International Physical Activity Questionnaire short form. Structural equation modeling was used to analyze the data. A bootstrapping method was used to determine and compare the direct and indirect effects of social support on PA across genders.Results:Peer support had no direct effect on PA; rather, peer support indirectly influenced PA through SE. Gender did not moderate this mediating effect. In addition, family support had neither a direct nor an indirect effect on PA via SE, and gender did not moderate these effects.Conclusions:Findings suggest that peer support played a more important role than family support on study participants’ PA indirectly through SE. SE also has a similar indirect effect across genders.

WAYS TO INCREASE PHYSICAL ACTIVITY OF STUDENTS BY USING AN ORGANIZATIONAL AND FUNCTIONAL MODEL AND ITS ASSESSMENT

2020 ◽  
Author(s):  
Юлия Николаевна Беляева ◽  
Галина Николаевна Шеметова ◽  
Эдуард Андреевич Тян ◽  
Евгения Евгеньевна Врабие ◽  
Владислав Валерьевич Ашевский
Keyword(s):  
Physical Activity ◽  
Young People ◽  
Functional Model ◽  
Urban Infrastructure

Учитывая задачу, поставленную экспертами ВОЗ, о повышении физической активности населения, авторы изучили уровень физической активности студенческой молодежи, возможности её повышения в условиях городской инфраструктуры, сделали попытку создания организационно - функциональной модели повышения физической активности студенческой молодежи. WHO experts set a goal to increase the physical activity of the population. The authors of the article studied the level of physical activity of students. They suggested ways to improve it in the context of urban infrastructure. The authors made an attempt to create an organizational and functional model for increasing physical activity of young people.

PENGARUH KEADILAN ORGANISASIONAL TERHADAP KOMITMEN ORGANISASIONAL MELALUI VARIABEL INTERVENING KEPUASAN KERJA PADA KARYAWAN PT. LEMBAH KARET PADANG

2018 ◽  
Vol 3 (2) ◽  
pp. 248
Author(s):  
Jefri Candika ◽  
Lucy Chairoel
Keyword(s):  
Job Satisfaction ◽  
Organizational Commitment ◽  
Path Analysis ◽  
Organizational Justice ◽  
Indirect Effect ◽  
Sampling Technique ◽  
Direct Impact ◽  
Indirect Influence ◽  
Analysis Technique

<p>Penelitian ini bertujuan untuk mengetahui pengaruh keadilan organisasional terhadap komitmen organisasional melalui variabel intervening kepuasan kerja pada karyawan PT. Lembah Karet Padang. Populasi dalam penelitian ini adalah berjumlah 308 orang dengan sampel sebanyak 75 orang karyawan, teknik pengambilan sampel menggunakan metode slovin. Teknik analisis yang digunakan dalam penelitian ini adalah teknik analisis path (<em>path analysis</em>) menggunakan SPSS. Dari hasil penelitian ditemukan keadilan organisasional berpengaruh positif dan signifikan secara langsung terhadap komitmen organisasional. Keadilan organisasional berpengaruh positif dan signifikan secara langsung terhadapa kepuasan kerja. Keadilan organisasional dengan kepuasan kerja sebagai variabel intervening berpengaruh positif dan signifikan terhadap komitmen organisasional. Pengaruh langsung keadilan organisasional terhadap komitmen organisasional lebih besar dari pengaruh tidak langsung melalui variabel kepuasan kerja. Dengan demikian dapat diartikan bahwa kepuasan kerja tidak memiliki pengaruh tidak langsung keadilan organisasional terhadap komitmen organisasional. Sehingga dapat disimpulkan bahwa kepuasan kerja tidak terbukti sebagai variabel intervening.</p><p> </p><p><em>This study aims to determine the effect of organizational justice on organizational commitment through intervening variable job satisfaction at employees of PT. Lembah Karet Padang. The population in this study was 308 people with a sample of 75 employees, sampling technique using slovin method. The analysis technique used in this research is path analysis technique (path analysis) using SPSS. From the results of the study found organizational justice has a positive and significant effect directly on organizational commitment. Organizational justice has a positive and significant impact directly on job satisfaction. Organizational justice with job satisfaction as intervening variable has a positive and significant effect on organizational commitment. The direct impact of organizational justice on organizational commitment is greater than indirect influence through job satisfaction variables. Thus it can be interpreted that job satisfaction does not have an indirect effect of organizational justice on organizational commitment. So it can be concluded that job satisfaction is not proven as intervening variable.<br /> <br /> </em></p>

The effect of psychological empowerment on job burnout and competitive advantage

2020 ◽  
Vol 18 (1) ◽  
pp. 47-71 ◽  
Author(s):  
Ali Safari ◽  
Arash Adelpanah ◽  
Razieh Soleimani ◽  
Parisa Heidari Aqagoli ◽  
Rosa Eidizadeh ◽  
...  
Keyword(s):  
Data Analysis ◽  
Organizational Commitment ◽  
Competitive Advantage ◽  
Indirect Effect ◽  
Psychological Empowerment ◽  
Job Burnout ◽  
Equation Modeling ◽  
Content Type ◽  
Mediating Role

Purpose This study aims at investigating the effect of psychological empowerment on job burnout and competitive advantage with the mediating role of organizational commitment and creativity. Design/methodology/approach The statistical population included all the managers and staffs of Tooka Company in Iran, and for data analysis, 120 completed questionnaires were used. Data analysis was carried out by SPSS 18 and Amos 20 software and structural equation modeling method. To test the mediating relationships, bootstrap method was used. Findings The findings showed that psychological empowerment has a significant direct effect on job burnout and competitive advantage. Also, psychological empowerment has a significant indirect effect on job burnout through the mediating role of organizational commitment. In addition, psychological empowerment has a significant indirect effect on competitive advantage through the mediating role of organizational creativity. Originality/value This study is among the first to investigate the relationship between psychological empowerment, job burnout, competitive advantage, organizational commitment and creativity.

Understanding How Cumulative Victimization Predicts Future Victimization Risk: Relevance of Cognitive Versus Social Mediation

2021 ◽  
pp. 073401682110157
Author(s):  
Thomas Wojciechowski
Keyword(s):  
Indirect Effect ◽  
Sensation Seeking ◽  
Service Providers ◽  
Social Factor ◽  
Equation Modeling ◽  
Mediation Effects ◽  
Systems Model ◽  
Victimization Risk ◽  
Increased Risk ◽  
Peer Association

Cumulative victimization represents the summation of victimization experiences across multiple contexts, with greater accumulation generally predicting greater dysfunction than less accumulation of exposures. Past research has indicated that cumulative victimization predicts increased risk for future revictimization also. The dual systems model may help to understand this relationship. This framework comprises constructs of sensation-seeking and impulse control in developmental context. Deviant peer association may provide a social factor that helps to understand this relationship. Victimization has been found to influence all of these constructs identified here. It is predicted that increased accumulation of victimization experiences may drive variation in these constructs that results in elevated risk for revictimization. This study sought to test the theory that each of these three constructs independently mediated the cumulative victimization–revictimization relationship. The Pathways to Desistance data were used in analyses. This sample was comprised of 1,354 juvenile offenders followed for 7 years after a recent adjudication prior to baseline measurements. The first three waves of data were used in analyses. Generalized structural equation modeling was used to test for the relationships of interest. A bootstrapping process of computing standard errors was carried out to determine significance of mediation effects. Results indicated that increased cumulative victimization scores at baseline predicted increased probability of experiencing victimization at Wave 3. This relationship was attenuated by about 15% when all mediators were added to the model and the relationship remained significant. Further analyses indicated that the specific indirect effect running through deviant peer association was significant, as was the total indirect effect. Findings indicate that increases in cumulative victimization may result in increased affiliation with deviant peers that further increases their future victimization risk. Service providers for survivors of violence should focus on screening of social relationships of those they provide care for in order to assess safety concerns.

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