Influence of type of contraction upon tendinous tissue during training: animal model

Introduction: The treatment of choice for tendinopathies is eccentric reeducation. Although the clinical results appear favourable, the biomechanical changes to the tissue are not yet clear.
Materiel and methods: This study compared the effects of two methods of training (eccentric (E) training and concentric (C) training) with untrained (U) rats. The animals underwent training over a period of five weeks. The tricipital, patellar and Achilles tendons were subsequently removed to perform a traction test to the point of tendon rupture, and a histological analysis was performed.
Results: There was a significant improvement in the rupture force of the patellar and tricipital tendons between the U and E groups. The tricipital tendons in the control group presented a significantly smaller cross-section than the E- and C-trained groups. No significant difference was observed for the constraints between the three groups for all three tendons. However, a tendency towards improvement was observed between the trained and the U groups for the patellar tendon. Histological studies demonstrated the development of a greater number of blood vessels and a larger quantity of collagen in the eccentric group.
Discussion and conclusion: The mechanical properties of tendons in rats improve after specific training, especially following eccentric training.