Health Consequences of Youth Sport Specialization.

Sport specialization is a training method now commonly used by young athletes who hope to achieve elite-level success. This may be defined as (1) choosing a main sport, (2) quitting all other sports to focus on 1 sport, and (3) year-round training (greater than 8 months per year). A number of sports medicine organizations have published recommendations based on the limited evidence available on this topic. The objective of this article was to perform a narrative review of the currently available evidence and sports medicine organizational recommendations regarding sport specialization and its effects on health to guide athletic trainers and sports medicine providers. To accomplish this goal, we conducted a narrative review of articles and position statements on sport specialization published from 1990 through 2018. Injury, overuse injury, serious overuse injury, and lower extremity injury were likely associated with higher degrees of sport specialization in various populations. Sports medicine organizations in general recommended against sport specialization in young athletes and instead promoted multisport participation for physical and psychological benefits. Few long-term data suggest that sport specialization has negative health-related quality-of-life consequences. Higher degrees of sport specialization likely pose risks of overuse injury; however, the age of specialization at which this risk occurs is not known. Because different populations and sports activities may put children at risk for certain injuries, future researchers should monitor large populations with sport-specific prospective active surveillance.

Relationship between chest lateral width, tube current, image noise, and radiation exposure associated with coronary artery calcium scanning on 320-detector row CT.

BACKGROUND: The relationship between chest lateral width, tube current, image noise, and radiation exposure on 320-detector row CT has not been reported. OBJECTIVE: We investigated the relationships between chest lateral width, estimated radiation exposure (DLPe), and image noise in 300 patients undergoing clinical coronary calcium scanning. METHODS: Patients undergoing coronary calcium scanning with 320-detector row CT (prospective, volumetric mode, 120 kV of tube voltage, 100-550 mA of tube current, 0.5-mm detector width) were grouped by chest lateral width (small, medium, and large) from anteroposterior topograms and 100 consecutive patients were selected from each group (n = 300). Tube current, DLPe, and noise were compared among groups with Kruskal-Wallis or one-way ANOVA. Phantom experiments were performed to evaluate the accuracy of calcium quantification as a function of size and tube current. RESULTS: Median tube current in small, medium, and large patients was 130, 200, and 250 mA, respectively (P < 0.0001). Despite the use of higher tube current settings, noise levels also increased with size (20.2 ± 4.5 HU, 22.0 ± 3.9 HU, and 25.1 ± 4.9 HU, respectively; global P < 0.001). DLPe was significantly higher with increasing size (54, 83, and 104 mGy · cm, respectively; P < 0.0001). Phantom experiments showed that 50-100 mA, 150-200 mA, and approximately 300 mA in small, medium, and large phantoms were associated with stable estimate of calcium. CONCLUSIONS: Increasing chest lateral width is associated with increasing radiation exposure and image noise. The use of 50-100 mA in small and 150-200 mA in medium patients is associated with acceptable noise and stable estimate of coronary artery calcium. In large patients, precise identification of individual calcified lesions remains difficult despite increasing tube current and radiation exposure.