Research Paper Volume 15, Issue 2 pp 308—352

Figure 4. Aging effects on EDL skeletal muscle weights and contractile force. Long-term endurance exercise protected against EDL skeletal muscle atrophy and contractile force loss during aging from 18 mo to 22 mo. HBW but not LBW, without exercise also protected against aging-related declines in these parameters in EDL muscle. (A) EDL muscle weight, (B) muscle weight/body weight (MW/BW) ratio, (C) absolute maximal contractile force, (D) specific maximal contractile force, (E) absolute submaximal contractile force and (F) specific submaximal contractile force in 18 mo and 22 mo LBW and HBW mice. ^*: p < 0.05, ^**: p < 0.01, ^***: p < 0.001. VWR vs. CTRL mice. Abbreviations: CTRL: control group; VWR: voluntary wheel running group; CBW: Combined groups (18 mo: n = 16 CTRL, n = 17 VWR; 22 mo: n = 8 CTRL, n = 8 VWR); LBW: Low body weight group (18 mo: n = 8 CTRL, n = 10 VWR; 22 mo: n = 4 CTRL, n = 4 VWR); HBW: High body weight group (18 mo: n = 8 CTRL, n = 7 VWR; 22 mo: n = 4 CTRL, n = 4 VWR).