## 4 Discussion  
Isokinetic dynamometers are often used for muscle strength measurement in athletes. Muscle strength is one of the important parameters that affects sports performance [2]. The aim of this study was to assess the intra- and inter-rater reliability of a well-used and a less-used IsoMed-2000 dynamometer for knee flexion and extension PT measurements in a concentric test in athletes. The intra- and inter-rater reliability of knee muscle strength measurements is fundamentally vital to both clinical and research considerations because muscle strength measurement is frequently used both in the determination of sports performance and in the stage of returning to sports after sports injuries [4]. The findings of this demonstrate the intra and inter-rater reliability of a well-used and a less-used IsoMed-2000 dynamometer for knee flexion and extension peak torque measurements in a concentric test in athletes. In this study, intra-rater reliability was moderate to excellent (ICCs: 0.516-0.928) for knee muscle strength parameters. Low standard errors of measurement (SEM) were observed in most of the measurements between trials (SEM:0.08-0.28 N/kg for old dynamometer and SEM: 0.08-0.29 N /kg for new dynamometer). The highest SEM and SDC95 were found in the EXDMPT60 and EXNDMPT60 measures for old and new dynamometers. SDC95 ranged between 0.24 to 0.76 for the old dynamometer and 0.25 to 0.80 for the new dynamometer. SDC% ranged between 9.50% to 24.79% for the old dynamometer and 11% to 26.87% for the new dynamometer. The highest SDC% were found in FLDMPT180, followed by the FLDMPT180 and EXNDMPT60 measures for old dynamometer. The highest SDC% were found in FLDMPT180, followed by the FLDMPT60 measure for the new dynamometer. At least 94.5% of the obtained values of parameters in the old dynamometer and 91.8% in the new dynamometer fell within the 95% limits of agreement. Inter-rater reliability was moderate to excellent (ICCs: 0.519-915) for knee muscle strength parameters. Low standard errors of measurement (SEM) were observed in most of the measurements between the old and new dynamometers (SEM: 0.08-0.29 N/kg for trial 1 and SEM: 0.09-0.29 N /kg for trial 2). The smallest detectable change (SDC95) ranged between 0.22 to 0.80 for Trial 1 and 0.25 to 0.81 for Trial 2. The highest SEM and SDC95 were found in the EXDMPT60 and EXNDMPT60 measures for old and new dynamometers. SDC% ranged between 8.75% to 26.74% for Trial 1 and 10.17% to 26.85% for Trial 2. The highest SDC% were found in EXNDMPT60 followed by the FLDMPT180 and FLDMPT180 measures for Trial 1. The highest SDC% were found in FLNDMPT60 followed by the EXDMPT60 and FLDM60 PT measures for Trial 2. At least 91.8% of the  
Figure 4: Bland–Altman plots for the inter-rater reliability of Trial 2 based on the mean of two dynamometers in eight measures. The first dashed line represents Mean–1.96 \(\times\) SD, the second dashed line represents Mean, and the third dashed line represents Mean + 1.96 \(\times\) SD. The grey circles indicate differences beyond the 95% confidence limits. obtained values of the parameters in Trail 1 and 89.2 % in Trial 2 fell within the 95% limits of agreement. When interpreting the results of our study, it is more accurate to interpret SDC% values instead of SEM and SDC95 because the measurement results are not standard. In a healthy athlete who has not suffered any injury, the strength of the knee flexors is always less than the strength of the knee extensor muscles [26]. In fact, it has been shown in the literature that the strength ratio of the knee flexor and extensor muscles is between 0.50-0.60 [26]. Considering the SDC95 value, it can be thought that knee extensor muscles with higher values are evaluated differently. Due to this situation, it would be more accurate to interpret the SDC% value instead of the SDC95 value.