library_construction_protocol: Achilles tendons were harvested by making a transverse incision just distal to the myotendinous junction and proximal to the enthesis. Tendons were measured manually using a tape measure and then divided into three equal segments – proximal, middle, and distal. Segments from each limb were combined into a single sample. Samples were minced and then pulse homogenized in Qiazol containing 1 ug of glycogen using a TissueRuptur (Qiagen, Germantown, MD, USA). To isolate RNA, a miRNA Micro Kit with added DNase I was used (Qiagen). Following RNA isolation, total RNA integrity was checked using a 2100 Bioanalyzer (Agilent Technologies, Santa Clara, CA). RNA concentrations were measured using the NanoDrop system (Thermo Fisher Scientific, Inc., Waltham, MA). Preparation of RNA sample library and RNA-seq were performed by the Genomics Core Laboratory at Weill Cornell Medicine. Messenger RNA was prepared using TruSeq Stranded mRNA Sample Library Preparation kit (Illumina, San Diego, CA), according to the manufacturer's instructions. The normalized cDNA libraries were pooled and sequenced on Illumina NovaSeq6000 sequencer with pair-end 50 cycles. The raw sequencing reads in BCL format were processed through bcl2fastq 2.19 (Illumina) for FASTQ conversion and demultiplexing.