## 4 Discussion  
The findings of the current research indicate an excellent correlation between the Stalker device (reference criterion) and the Bushnell radar, with an ICC of 0.989 for throwing the ball and 0.986 for kicking the ball. Additionally, a magnitude of error was observed, with the SEE ranging from 0.194 to 0.357 and a CV of 1.252% and 1.179% for throwing and kicking, respectively. Despite this, the maximum error of the estimate was 0.380 for throwing and 0.700 for kicking. Furthermore, the mean difference in kicking speeds was 1.38 km/h (95% CI: 1.20; 1.56), and in throwing speeds, it was 1.39 km/h (95% CI: 1.20; 1.59). However, the Bushnell radar reported lower ball speeds for both throws and kicks, with differences that are both statistically significant and of practical importance. Despite this discrepancy, the strong correlation between the two devices suggests that either can be used by practitioners as long as normative values are adjusted accordingly. Our results are consistent with a previous study [11] that reported good agreement (ICC \(\geq\) 0.98, r \(\geq\) 0.98) and very low error magnitude (SDC \(\leq\) 7.70 km-h\({}^{-1}\), CV \(\leq\) 2.23%) when comparing the Stalker radar with the Pocket radar. The strong correlation between different radar devices reinforces the reliability of using lower-cost alternatives, such as the Pocket radar, for accurate speed measurements in various sports settings. The findings from previous research demonstrate the potential for these more affordable devices to provide data comparable to that of the high-end Stalker radar, thereby making advanced performance analysis more accessible to a broader range of users [11]. The findings of the present study also align with another study [17] that compared the Pocket radar and Speedtrack X radar, which reported a high correlation between the data obtained from the two devices (r = 0.932, \(p\) < 0.001). The ICC of the measurements of the data obtained from the two devices was high (r = 0.964, \(p\) < 0.001). These findings highlight the consistent performance of various radar guns across different brands and models, suggesting that technological \begin{table}
\begin{tabular}{c c c c} \hline \hline  & & **Stalker vs. Bushnell** & **Stalker vs. Bushnell** \\  & & **(Throw)** & **(Kick)** \\ \hline Magnitude of error & & & \\  & SEE (km/h) & 0.194 & 0.357 \\  & CV (\%) & 1.252 & 1.179 \\  & MEE (km/h) & 0.380 & 0.700 \\ Absolute Agreement & ICC & 0.989 & 0.986 \\  & ICC (95\%CI lower) & 0.986 & 0.983 \\  & ICC (95\%CI upper) & 0.991 & 0.989 \\ Analysis of variance & & & \\  & t & 14.293 & 15.227 \\  & \(p\)-value & \textless{}0.001 & \textless{}0.001 \\  & [PERSON]’s d & 0.799 & 0.851 \\  & [PERSON]’s d (95\%CI lower) & 0.673 & 0.979 \\  & [PERSON]’s d (95\%CI upper) & 0.924 & 0.723 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Concurrent validity of the Bushnell and Stalker radar for the ball speed in throw and kick. advancements in radar devices have reached a point where even budget-friendly options can yield reliable and accurate results. Moreover, the consistency across these studies, including our own, suggests that the variations in measurement between different radar guns are minor and likely within an acceptable range for most practical applications in sports science. For instance, this close agreement across radar models makes them viable tools for use in player development settings, where performance monitoring is essential for tracking progress and informing training adjustments. Coaches can confidently use Bushnell radar devices to evaluate speed improvements, as long as they adjust for the 1.4 km/h difference if precise speed thresholds are important for setting or evaluating performance targets. This consistency is crucial for practitioners who may need to interchangeably use different radar guns depending on availability, cost, or specific application needs.