DELETION OF INDIVIDUAL MUSCLES ALTERS RAT WALKING-TRACT PARAMETERS

Rat walking-track analysis has been employed extensively to quantify m otor recovery in studies of hindlimb nerve injury and repair. in order to clarify the relationship between individual print measurements and the function of specific hindlimb muscles, 40 young adult rats were a ssigned to one of five groups (n = 8/group) in which specific deletion s of motors were created as follows: Group 1-division of the tendon of insertion of the gastrocnemius, soleus, and plantaris muscles (CSP); Group 2-division of the extensor digitorum longus muscles tendons of i nsertion (EDL); Group 3--division of the extensor hallicus longus musc le tendon of insertion (EHL); Group 4-division of the tibialis anterio r muscle tendon of insertion (TA); or Group 5-division of the tibial n erve at the ankle (TNA). Parameters for print length (PL), intermediat e toe spread (IS), and total toe spread (TS) were calculated from walk ing tracks recorded before and again five days after deletion of the m otors. Specific, predictable patterns of change in footprint parameter s were observed for each group. It was concluded that triceps surae an d tibialis anterior muscle function directly affects print length; EHL function directly influences total toe spread; and EDL function is di rectly related to intermediary toe spread. These data demonstrate a di rect relationship between individual print measurements and the functi on of individual rat hindlimb muscles.