Inflammatory mechanisms linking the sports practice at high intensity and bone development in adolescents

Author(s)

Ricardo Ribeiro Agostinete

• Document type: Master's Dissertation
• Press: Presidente Prudente. 2017-07-18.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências e Tecnologia. Presidente Prudente
• Defense date: 2017-05-26
• Advisor: Romulo Araújo Fernandes

Abstract

Introduction: Physical exercise practice can induce bone mass responses, such as elevation of metabolism biochemical markers, secreted by osteoblasts in the bone matrix formation and calcification process. However, high intensity training is related with elevated pro-inflammatory markers, which can attenuate the process related with bone mass gain. Objectives: To compare bone mass/density gain during nine months, as well identify the impact of training load and inflammation in this outcome. Methods: Nine months cohort. Sample was composed by adolescents, divided in to groups: sports practitioners (adolescents engaged in swimming and basketball practice) and control group. The adolescents were included in the sample whether present the following inclusion criteria: i) aged 11 to 17 years old; ii) do not present any metabolic disorders; iii) do not consume regular medications for blood pressure and lipid profile control; iv) practice only on sport modality during the last 12 months; v) practice at least 12 months in the current sport modality; vi) signature of consent and clarified term by the tutor. For the control group (with the exception for iv and v items), this last criteria will be added: vii) do not practice any sport modalities during the last 12 months. Inflammation, measured using c-reactive protein (CRP), were the outcomes analyzed. Load training was measured using an individual notebook of daily load control, through the rating of perceived exertion (RPE) and body composition were analyzed using DXA (dual-energy x-ray absorptiometry scanner). Statistical analysis was controlled by confounders, such as biological maturation, age, food intake frequency and sex and were analyzed using the BioEstat software with p-value <0.05. Cross Sectional Results: Swimmers had lower bone density than control, however higher CRP values; there was a significant and positive relationship between training load and fat free mass (muscle mass). In boys, the training load presented a negative correlation with bone density in the lower limbs (r = -0.293 [95% CI: -0.553 to -0.034]). In girls, the training load was negatively related to BMD in the lower limbs (r = 0.563 [95% CI: -0.770 to -0.356]) and total body (r = - 0.409 [95% CI: -0.609 to -0.209]). Longitudinal Results: Swimmers and basketball players presented higher values of inflammation (CRP) at baseline. The monthly training load was positively related to fat free mass independent of the effect of confounding factors, such as inflammation, in both modalities. However, there was no negative relationship between training load and gain of bone mineral density after adjustment. Conclusion: The training load had a negative relation on the bone density of swimmers of both sexes, regardless of the positive effect of MLG on bone density. However, gains in bone mass during the 9-month follow-up were similar between groups and the training load did not influence bone mineral density gains after considering the effect of the covariates (inflammation, maturation, age and practice of resistance training. (AU)

• FAPESP's process: 15/13543-8 - Inflammatory mechanisms linking sports practice at high intensity and bone development in young
• Grantee: Ricardo Ribeiro Agostinete
• Support Opportunities: Scholarships in Brazil - Master