# Isokinetic Strength in Peritoneal Dialysis Patients: A Reliability Study
## 4 Discussion
\begin{table}
\begin{tabular}{l c c c c c} \hline \hline  & **Age** & **Height** & **Weight** & **BMI** & **Fat Mass \%** & **Lean Mass \%** \\ \hline Knee Concentric Extension Peak Torque & \(-0.314\) & \(0.450\) * & \(0.015\) & \(-0.327\) & \(-0.290\) & \(0.279\) \\ Knee Concentric Extension Work & \(-0.199\) & \(0.554\) ** & \(0.143\) & \(-0.279\) & \(-0.337\) & \(0.319\) \\ Knee Concentric flexion Peak Torque & \(-0.040\) & \(0.436\) * & \(0.268\) & \(-0.082\) & \(-0.258\) & \(0.249\) \\ Knee Concentric Flexion Work & \(-0.071\) & \(0.455\) * & \(0.221\) & \(-0.150\) & \(-0.297\) & \(0.285\) \\ Elbow Concentric Extension Peak Torque & \(0.087\) & \(0.728\) ** & \(0.455\) * & \(-0.185\) & \(-0.522\) ** & \(0.508\) ** \\ Elbow Concentric Extension Work & \(0.075\) & \(0.647\) ** & \(0.396\) * & \(-0.129\) & \(-0.414\) * & \(0.393\) * \\ Elbow Concentric Flexion Peak Torque & \(0.266\) & \(0.506\) ** & \(0.529\)** & \(0.041\) & \(-0.269\) & \(0.274\) \\ Elbow Concentric Flexion Work & \(0.132\) & \(0.634\) ** & \(0.509\) ** & \(-0.021\) & \(-0.363\) * & \(0.342\) \\ \hline \hline \end{tabular}  
* \(p<0.05\); ** \(p<0.01\); BMI, Body mass index.  
\end{table} 
Table 4: Correlations between isokinetic strength and anthropometric and body composition variables. reported here to evaluate whether an observed change in lower or upper limb strength represents a true change or not. Almost every measure achieved an excellent reliability according to the classification by [PERSON], [PERSON], and [PERSON] [18]. The ICC in elbow flexion in men was lower than 0.90; thus, it was classified as \"good\" but not \"excellent\". On the other hand, the reliability of this measure was excellent among women. Regarding the SRD, which is the parameter that defines the threshold to consider an observed change as \"true\" or \"real\", the values for the knee peak torque ranged between 20.70% in the knee concentric flexion of women and 31.29% in the knee concentric extension of men. Regarding the elbow's peak torque, it ranged between 11.84% in the concentric flexion of women and 24.56% in the concentric extension of men. Overall, higher reliability was observed in women compared to men, and the SRD was lower in the concentric flexion compared to the concentric extension. This was also observed when assessing the work. Although hypothetical, these sex differences might be related to the significant differences between men and women observed at baseline, i.e., age, height, weight, fat mass, and lean mass. However, given the relatively low sample size, this finding must be taken with caution. The current study has some limitations. First, the participants did not undergo a familiarization session because of time and financial constraints. Second, although the sample size was similar to or even higher than those from previous studies [15; 30; 31], results from the stratification by men and women must be taken with caution. Third, the mean age of males was 52.42, which means that they were more than 10 years older than the women; thus, comparison between males and females could be influenced by that age difference. Despite these three limitations, the current study provides useful information about the reliability of isokinetic measures in people undergoing PD.