## 3 Results  
### Descriptive Statistics and Reliability  
All participants completed the full set of measurements, and no data were discarded. The descriptive statistics with reliability analyses are available in Tables 1 and 2 for the ankle and knee extension tasks, respectively. Males produced higher peak forces than females in the ankle extension task (375.0 \(\pm\) 57.2 N vs. 267.1 \(\pm\) 51.9 N; \(p\) < 0.001) and knee extension task (721.8 \(\pm\) 158.1 N vs. 434.6 \(\pm\) 114.2 N; \(p\) < 0.001). Regarding the ankle extension, the reliability was good for most of the RFD variables. The peak RFD showed good (ICC = 0.81) and moderate (ICC = 0.69) relative reliability for the ankle task in sustained and ballistics contractions, respectively. The early RFD (0-50 ms) also had only moderate reliability for the ballistic contractions (ICC = 0.61). For the sustained contractions, the RFD in later and longer intervals (100-150, 150-200 ms) and also in 0-150 and 0-200 ms reached excellent reliability scores (ICC = 0.92-0.95). Typical errors ranged between 7.3% and 22.9% for the sustained contractions and between 8.6 and 33.3% for the ballistic contractions. For both contraction types, the typical errors notably decreased as the time interval increased. Regarding the knee extension task, the reliability was also good for most of the outcome variables. The peak RFD showed only moderate reliability for the knee task, for both contraction types (ICC = 0.59-0.61). Moreover, only moderate reliability was found for variables for the 0-50 ms time interval for both sustained (ICC = 0.61) and ballistic contractions (ICC = 0.65). Excellent reliability was found only for the RFD at 0-200 ms \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Outcome Variable** & **Mean** & **SD** & **ICC (95\% CI)** & **TE (\%)** \\ \hline \multicolumn{4}{c}{Sustained Contractions} \\ \hline Peak force (N) & 322.7 & 76.8 & 0.98 (0.97–0.99) & 3.8 (3.3–4.6) \\ Peak RFD (N/s) & 2338.4 & 613.1 & 0.81 (0.65–0.92) & 13.12 (7.8–19.2) \\ RFD 0–50 (N/s) & 1146.0 & 434.9 & 0.78 (0.66–0.87) & 22.2 (19.1–26.8) \\ RFD 0–100 (N/s) & 1427.1 & 467.9 & 0.87 (0.78–0.92) & 14.5 (12.5–17.6) \\ RFD 0–150 (N/s) & 1363.1 & 394.0 & 0.92 (0.87–0.96) & 9.4 (8.1–11.4) \\ RFD 0–200 (N/s) & 1211.5 & 331.4 & 0.95 (0.91–0.97) & 7.4 (6.4–8.9) \\ RFD 50–100 (N/s) & 1589.8 & 566.4 & 0.85 (0.76–0.91) & 16.6 (14.3–20.1) \\ RFD 100–150 (N/s) & 1537.7 & 455.4 & 0.92 (0.87–0.95) & 9.8 (8.4–11.8) \\ RFD 150–200 (N/s) & 1375.6 & 380.3 & 0.95 (0.91–0.97) & 7.3 (6.3–8.8) \\ \hline \multicolumn{4}{c}{Ballistic Contractions} \\ \hline Peak RFD (N/s) & 2994.8 & 1766.1 & 0.69 (0.44–0.82) & 24.12 (12.1–38.7) \\ RFD 0–50 (N/s) & 1109.1 & 711.9 & 0.61 (0.46–0.74) & 33.3 (29.5–38.8) \\ RFD 0–100(N/s) & 1562.4 & 720.9 & 0.82 (0.73–0.89) & 15.0 (13.3–17.5) \\ RFD 0–150 (N/s) & 1532.7 & 589.2 & 0.89 (0.83–0.93) & 9.3 (8.2–10.8) \\ RFD 0–200 (N/s) & 1340.0 & 494.1 & 0.88 (0.82–0.93) & 10.5 (9.3–12.2) \\ RFD 50–100 (N/s) & 1765.7 & 915.6 & 0.78 (0.68–0.87) & 18.0 (15.9–21.0) \\ RFD 100–150 (N/s) & 1820.4 & 679.0 & 0.88 (0.82–0.93) & 10.2 (9.0–11.9) \\ RFD 150–200 (N/s) & 1597.9 & 542.8 & 0.90 (0.84–0.94) & 8.6 (7.6–10.0) \\ \hline \hline \end{tabular} SD—standard deviation; ICC—intraclass correlation coefficient; CI—confidence interval; TE—typical error; RFD—rate of force development.  
\end{table} 
Table 1: Descriptive statistics and reliability analysis for ankle extension task.