Day-0 elongation negatively correlated with 7-day expression of Col XII (A.1), MMP2 (B.1), and TIMP3 (C.1). Shown is percentage of tendons that were fatigue loaded within the primary and secondary phase of each cluster (A.2, B.2, and C.2), 7-day gene expression (avgs and std devs) (A.3, B.3, and C.3), and coinciding day-0 elongation (avgs and std devs) (A.4, B.4, and C.4).