Adaptations in the myotendinous interface of wistar rats after resisted training - morphological, biochemical and functional analysis

Abstract

In the face of resisted physical activities on the hypertrophy model, the primal area characterized by injuries predisposition and high plasticity as a result of exercises is known as myotendinous junction (MTJ). That is functionally the major strength transmitter of the muscular system to tendons. The present study has as main goal the analysis of morphological, biochemical and functional alterations on gastrocnemius muscle of adult Wistar rats, after hypertrophy model training. To this end, will be used 30 rats aged 90 days from the UNESP Botucatu Animal House, randomly divided in three groups: C - Control (n=10); CL - Climb (n=10); and RCL - Resisted Climb (n=10). During two months, the CL and RCL groups will perform the 24 sessions vertical climb protocol, 4-9 climbs and 8-12 dynamic movements per session. Only in the RCL group will be added a progressive load during the climbs, each attempt with 50%, 75%, 90% and 100% of each individual body mass, with an extra of 30g for each subsequent climb. The CL group will execute the same training protocol without the extra load adding after 100%, both weekly measured for adjustments and future body mass analysis. The images will be obtained through transmission electron microscopy and light microscopy techniques, in order to identify structural and ultrastructural organization in MTJ components. According to protocol directions, it is expected to see both distal sarcomere reorganization and greater tendinous sarcoplasmatic invagination and muscular sarcoplasmatic evagination length and thickness near the MTJ area in trained groups, with accentuated results in RCL group. For the C group, it is expected to examine the lack of development of MTJ components. Thus, the resisted physical activities benefits includes the gain of muscular mass and strengthening of MTJ area, helping to lower the risks of further injuries.