[Assessment of the frequency of a decrease in bone mineral density and its relationship with the diet of young tennis players].

Abstract

Optimizing bone health is a key aspect of injury prevention both in the general population and in youth sports. Furthermore, the specifics of physical activity, along with nutrition, are potentially modifiable factors influencing the skeletal system. Assessing the relationship and further optimizing dietary intake and bone health is an important component of a comprehensive system of medical and biological monitoring of young athletes. The purpose of this study was to assess the incidence of decreased bone mineral density (BMD) and its relationship with dietary intake in young tennis players.

Material and methods: The study involved 60 tennis players aged 7 to 17 years (33 female, 27 male). Dietary intake was assessed using 24-hour dietary recall for 3 survey days (2 training days and 1 day off) and food-frequency methods (for 1 month preceding the survey). BMD of the forearm and lower leg was assessed using ultrasound densitometry.

Results: The prevalence of reduced BMD (Z-score <-2.0 SD) in primary school-aged children was 37.5% for the radius and 20.8% for the tibia. Among children aged 11-14 years, low BMD of the radius was observed in 23.5% of those examined, and of the tibia in 11.8%, while in the older age group, only one of the 8 athletes had low BMD of both areas examined. One of the positive factors influencing bone tissue could be the effect of tennis-specific impact loading, which becomes apparent with increasing skill. Dietary imbalance consist of carbohydrate deficiency, which is most pronounced when calculated per kg of body weight in young men aged 15-17 years, girls aged 11-14 and 15-17 years, among whom not a single athlete had carbohydrate consumption reaching the lower limit of the recommended intake range. A surplus of dietary fat was observed regardless of age and gender, with a maximum intake of 3.8 g/kg body weight per day. A specific energy deficit was observed in girls aged 11-14 and 15-17. A positive correlation was noted between daily calories from protein and Z-score in the radius area of boys aged 7-10 years. A negative correlation was found in the group of senior school-age boys between fat intake in absolute and specific units and the BMD of the radius.

Conclusion: Based on the study of the frequency of low BMD and its correlation with dietary intake, individual recommendations for adjusting the diet of young tennis players have been developed. X-ray osteodensitometry is recommended for athletes at risk. A comprehensive analysis of nutrition and physical development indicators allows for the timely identification of risks and the development of recommendations for optimizing the level of physical activity and diet of young tennis players to improve bone health.