The present study shows chronic adjustments in the myotendinous junction (MTJ) in response to different ladder-based resistance training (LRT) protocols. Thirty adult male Wistar rats were divided into groups: sedentary (S), calisthenics (LRT without additional load [C]), and resistance-trained (LRT with extra weight [R]). We demonstrated longer lengths of sarcoplasmatic invaginations in the trained groups; however, evaginations were seen mainly in group R. We showed a greater thickness of sarcoplasmatic invaginations in groups C and R, in addition to greater evaginations in R. We also observed thinner basal lamina in trained groups. The support collagen layer (SCL) adjacent to the MTJ and the diameters of the transverse fibrils were larger in R. We also discovered a niche of telocytes in the MTJ with electron micrographs of the plantar muscle and with immunostaining with CD34+ in the gastrocnemius muscle near the blood vessels and pericytes. We concluded that the continuous adjustments in the MTJ ultrastructure were the result of tissue plasticity induced by LRT, which is causally related to muscle hypertrophy and, consequently, to the remodeling of the contact interface. Also, we reveal the existence of a collagen layer adjacent to MTJ and discover a new micro anatomic location of telocytes. The myotendinous junction (MTJ) consists of a highly specific anatomical region in which the sarcoplasmatic membranes connect to bundles of extracellular matrix (ECM) collagen fibers 1. Due to its functionality, MTJ represents the region with the highest transmission of force 2,3. Morphologically, MTJ presents projections that penetrate the muscle tissue, parallel and directed to the myofibrils, forming sarcoplasmatic invaginations. Currently, we know that its development is mainly influenced by the interactions between myoblasts and ECM elements 4,5. The basal lamina of muscle fiber creates a supramolecular connection structure composed of different levels of proteins from the laminin and collagen polymers located in the ECM 6. This arrangement contributes structurally to the transmission of force, adapting, remodeling, and consequently affecting the macroscopic tendon structure to different stimuli 7,8. Initially, telocytes were described as interstitial Cajal cells 9. Telocytes are interstitial cells of stromal origin with an oval shape, and a heterochromatic nucleus with moniliform projections denominated telopodes, which characterize its morphological classification according to the number of projections 9,10. They are founded in the interstitium of tissues such as the testicle 9 , smooth and cardiac muscle 11 , human tongue 10 , pancreas 12 , and liver 13. It can be identified by the electronic microscopy, immunohistochemistry, and CD34+/immunostaining 14. Recently, telocytes have been found in proximity to and engaging in possible interactions with satellite cells 10. The telocytes projections have terminals (pods) with mitochondria that form junctions with adjacent cells, and they have caveolae that perform exocytos...