TRAINING EFFECTS ON SOLEUS OF CATS SPINAL-CORD TRANSECTED (T12-13) ASADULTS

Adult spinal cord transected (T12-13) cats were trained for 30 min/day , 5 days/week to either step on a treadmill (Stp-T) or stand (Std-T) f or similar to 5 months. Training ameliorated soleus atrophy and enhanc ed maximum force capability compared to nontrained (N-T) spinal cats, with Stp-T being significantly different from N-T. Isometric twitch sp eed and maximum rate of shortening were unaffected by training; the so leus of all spinal groups was significantly faster than control. There was an elevation in myosin adenosine triphosphatase activity and a sh ift toward faster myosin heavy chain and fiber type compositions in N- T and Std-T, but not Stp-T cats. Thus, rhythmical activity involving m uscle length and force changes (stepping) was more effective than a si milar amount of a more static activity (standing). This specificity re lated to the type of training should be considered when developing reh abilitative strategies following spinal cord injury. (C) 1998 John Wil ey Sons, Inc.