library_construction_protocol: Tissue collection occurred over several months and tissues from the same age group (n = 8-12 per group) were collected on the same day between 9am and 1pm. Prior to tissue collection, mice were killed by CO2 asphyxiation. Diaphragm, gastrocnemius, soleus, and tibialis anterior muscles were preserved in RNA later and stored at -80℃. RNA was extracted from tissues preserved in RNA later using MagMax-96 Total RNA isolation kit (Thermo Fisher). The RNA concentration was quantified using NanoDrop Spectrophotometer (NanoDrop Technologies) and the integrity assessed using Fragment Analyzer (Agilent). The RNA concentration was quantified using NanoDrop Spectrophotometer (NanoDrop Technologies) and the integrity assessed using Fragment Analyzer (Agilent). Strand specific total RNA-seq libraries were prepared using Kapa RNA HyperPrep kit (Roche) with Fastselect rRNA HMR ribosome RNA removal kit (Qiagen).