Fig 1: The bmx mouse has reduced motor function, muscle force and heart function. (A) Grip strength of bmx mice was reduced in both the forelimb (P = 0.0465) and hindlimb (P = 0.0002) grip strength tests. n = 8. (B) Suspension time of bmx mice was reduced in the wire hang test (P = 0.0087) and in the box hang test (P = 0.0489). n = 8. (C) In vivo maximum isometric torque and torque-frequency curve for anterior crural muscles of WT, bmx, and mdx52 mice. Maximum isometric torque was reduced in bmx mice (P = 0.0110). n = 6–7. (D) Left; ex vivo eccentric contraction-induced lengthening force drop in EDL, bmx shows increased injury (force drop) versus WT. (P = 0.0249); right; force drop, expressed as a percent of initial eccentric contraction force, is shown across 10 eccentric contractions. (E) Echocardiography of aged (18-month-old) bmx mice shows a deficit in heart function through a decrease in fractional shortening (P = 0.0036) and ejection fraction (P = 0.0131). n = 5–7. (F) Representative M-mode images of the parasternal short axis are provided. (G) Serum CKM levels in aged (1-year-old) mice assayed via ELISA. n = 6–7. ANOVA, *P = 0.05, **P = 0.01, ***P = 0.001, ****P = 0.0001.