Biomechanical testing. (A) Box-and-Whiskers plot of the peak forces measured at tendon failure. (B) Ratio of the peak forces assessed at failure in intact and surgically treated tendons. (C) Box-and-Whiskers plot of the tendon stiffness. (D) Ratio of the stiffness of intact and surgically treated tendons. (E) A representative characteristic load–displacement curve from a tensile test of an Achilles tendon. Groups A and C contain intact (unoperated) tendons, group B contains surgically operated tendons without the application of mesenchymal stromal cells (hMSCs), group D contains surgically operated tendons with the application of hMSCs. Group I represents animals without hMSC treatment. Group II represents animals with hMSC treatment. The grey boxes indicate the interquartile range, the whiskers indicate the 10–90 percentile range, and the small red circles indicate values more than 1.5 times IQR above or below the boxes (○). Any points more than 3 times IQR above or below the box are indicated by circles with superimposed plus signs (⊕). A horizontal line is drawn at the median. The plus signs inside the boxes indicate the arithmetical averages.