## 4 Discussion
### Biological and Injury Profile Characteristics  
The descriptive data for the injury prevalence, injury rate and injury profile were quite similar to the results of previous studies [8; 15; 16]. The injury prevalence and injury rate in Portuguese school-age children presented meaningful results. Lower and upper limbs were the most affected areas, and strains, strains and fractures were the major injuries registered. This sample did not present significant differences between the decimal age and bone age. Nonetheless, the maturity offset mean and standard deviation showed that the majority of the study participants were in or near the PHV stage. The recorded PA intensities for both sexes were mainly moderate. The daily times spent on vigorous and very vigorous PA were low. Portuguese children and adolescents do not undertake sufficient PA as recommended by international health guidelines [56; 57]. PA of vigorous intensity accounts for the lowest proportion of the overall PA among young people and may decline more rapidly than PA of any other intensity during this period [58]. The age group results also showed that, as age increases, the time spent on MVPA decreases. Although it is widely accepted that the PA intensity rises with age, studies have consistently shown that PA declines throughout adolescence [59; 60], especially vigorous PA [58]. The time available for PA is reduced in this transition from childhood to adolescence. Despite the steady increase in organized sport participation during the last few years, the evidence shows that active play during leisure as well as non-organized sport activities seems to \begin{table}
\begin{tabular}{l l c c c c} \hline \hline
**Injury Type 1** & **Predictor** & **B(SE)** & \(p\) & \
\begin{tabular}{c} **Odds** \\ **Ratio** \\ \end{tabular} &
\begin{tabular}{c} **95\% CI Odds** \\ **Ratio** \\ \end{tabular} \\ \hline \multirow{3}{*}{Strain} & Constant & 3.794 (4.180) & 0.364 & \multirow{3}{*}{(1.003, 1.080)} \\  & Time spent on & & & & \\  & moderate PA & 0.040 (0.019) & 0.035 & 1.041 & (1.003, 1.080) \\  & Bone age & \(-0.549\) (0.246) & 0.025 & 0.577 & (0.357, 0.935) \\ \hline \multirow{3}{*}{Fracture} & Constant & 3.744 (4.313) & 0.385 & \multirow{3}{*}{(1.001, 1.080)} \\  & Time spent on & & & & \\  & moderate PA & 0.039 (0.019) & 0.044 & 1.040 & (1.001, 1.080) \\ \cline{1-1}  & Bone age & \(-0.555\) (0.254) & 0.029 & 0.574 & (0.349, 0.944) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Multinomial logistic regression model for injury type. be decreasing due to increasing access to technology and other activities [56]. Also, other responsibilities can arise such as part-time jobs or more hours devoted to studies [60]. Moreover, influences from the school environment and peer groups can strongly affect PA behaviors [60; 61]. The maturity offset and bone maturity category group results presented a similar pattern. The participants before PHY and late maturers spent more time on MVPA than the other maturity groups. This supports the fact that maturation is a significant variable concerning PA participation. The hormonal fluctuations involved in puberty tend to create marked changes in body composition. Adolescents become taller and heavier, and there is an increase in adipose tissue, especially in girls [62]. A lower proficiency in motor skills may also become present [30; 31]. All of these factors can discourage adolescents from regular PA.  
As expected, there were also differences between the sexes in the time spent on PA at different intensity levels. The boys consistently spent more time on moderate, vigorous and very vigorous PA. Boys are less sedentary and more active than girls at all ages [57; 58; 60; 61], and girls tend to have lower involvement in PA, especially those who mature earlier [16; 62]. Boys are usually more active and have more freedom to explore outdoors [61; 63]. Moreover, they seem to receive more encouragement from parents to practice PA compared to girls [60].