Figure 6

Biomarkers calculated on string pulling kinematic traces directly translate to human subjects with shoulder injury. (a) Representative control subject with three cycles of string pulling superimposed. Elbows were labeled in addition to hands for the human patients given the ready visibility of human elbows. (b) Same subject as in (a), data shown for one full trial. Note similarity of kinematic trajectories for the hands between human and rodent subjects (Fig. 2b). (c) FWHM measurements for control (n = 12) and injured shoulders (n = 6). Inset shows zoomed view for FWHM values between 0 to 100. *** < 0.001, Kolmogorov-Smirnoff test. (d) Left, histogram of velocity values (calculated on the Y-axis kinematic trajectories of the hands) for control (n = 6), injured (n = 6), and contralateral uninjured (n = 6) shoulders. Right, same as left only for acceleration values. ***< 0.001, Kruskal–Wallis test. (e) Quantification of absolute Eigenvector weights for the first PC (data shown for Y-axis Eigenvector weights of the hands). Gray lines show change between injured and contralateral uninjured shoulders for each trial recorded per subject. *< 0.1, one-way ANOVA (f, g) Amplitude and time of reach (solid line) and pull (dashed line) epochs. Individual amplitude/time values for every cycle of string pulling shown for reaches and pulls with circles and triangles, respectively. (h) Ratio of standard deviation values between ipsilateral hand:elbow pairs calculated for each subject on their hand/elbow Y-axis kinematic trajectories. Gray lines show change between injured and contralateral uninjured shoulders for each trial recorded per subject. *< 0.05; **< 0.01; ***< 0.001, two-way ANOVAs, Tukey multiple comparison corrected post-hocs for all other statistical analyses unless stated otherwise. (i) Receiver operating characteristic (ROC) curve for a binary logistic regression model fitted to predict a patient as either having no RC tear or having an RC tear in one of their shoulders. Maroon line shows mean ROC across threefold stratified cross-validation, gray outline plots ± 1 Std. Dev. uncertainty in the mean ROC estimate. All statistics are given in Supplementary Table 2.