Performance of the three optimal feature sets under three studied disturbances. The three feature sets are (A) mAV, waveLen, AR, and Ceps; (B)waveLen, logDetect, AR, and Ceps; (C)waveLen, wAmp, AR, and Ceps. Each graph is divided into three columns. The first column shows classification accuracies for each subject with respect to location stability. The second column shows classification accuracies for each subject with respect to effort stability. Only the classifier trained on low effort data and tested on high effort data was considered. The third column shows classification accuracies with respect to fatigue stability. Horizontal black lines in each column of all the graphs show the mean classifier performance across all subjects for the stability condition.