Responsiveness of the Calf-Raise Senior Test in community-dwelling older adults undergoing an exercise intervention program

Introduction: Mobility significantly depends on the strength in the ankle muscles, which are particularly relevant in mobility. There are few assessment tools of ankle strength validated for all psychometric properties. The main purpose of this study was to test the responsiveness of Calf-Raise Senior Test, in order to detecting improvements in plantar-flexor strength/power of elderly participants after a 24 weeks exercise intervention.Methods: 82 older adults participated in an exercise program and were assessed with CRS Test and 30-seconds chair stand test at baseline and at follow-up. Effect size, standardized response mean and minimal detectable change measures of changes were determined using Calf-Raise Senior and chair stand tests scores. ROC curves analysis was used to define a cut-off representing the minimally important difference of Calf-Raise Senior test.Descriptive statistics analyses were performed to allow the sample characterization. Central tendency parameters were determined for continuous variables (mean, standard deviation and median) and relative frequency was calculated for categorical and ordinal variables. The normal distribution of continuous variables was checked with the Kolmogorov-Smirnov Test. Differences in scores between groups of change (stables vs improved) at BL and FU were tested by the Independent samples t-tests (or non-parametric Mann-Whitney U test when appropriate), and Paired t-tests (or non-parametric Wilcoxon tests) were used to compare data at BL and FU within groups.The responsiveness of the CRS test was determined using two different methods of sensitivity to change analysis aiming at evaluating the capacity of this tool to identify important and meaningful changes occurred in the plantar-flexor’s strength of participants after the intervention. A distribution-based approach was employed to assess the magnitude of changes in the scores, using statistical parameters, which are related to sample variability and measurement precision (Crosby, Kolotkin, & Williams, 2003; Lauridsen, Hartvigsen, Manniche, Korsholm, & Grunnet-Nilsson, 2006; Middel & Van Sonderen, 2002; Revicki, Hays, Cella, & Sloan, 2008). In order to analyze the interpretability of the results (i.e., to determine what would be the qualitative meaning of the CRS test quantitative scores), an anchor-based analysis was also applied in this study (Terwee et al., 2007; Terwee et al., 2010). These approaches have advantages and limitations, and some authors