So the achilles is tricky because it’s not a muscle. I don’t think you can really make it stronger. You probably need to strengthen other muscles around it. Or you may need to rest more. If you’re putting a lot of strain on your heels then you may need to do less tkd per week. The last thing you want to do is tear your achilles. Definitely avoid stretching. There is no science supporting its proclaimed benefits. Maybe some calf raises once a week will help?
Discussion
Tendons and ligaments can be strengthened through specific types of exercise and mechanical loading.
Research indicates that resistance training, particularly involving high strain magnitude and appropriate strain duration, can enhance tendon stiffness, cross-sectional area, and Young's modulus. For example, a study by Bohm et al. demonstrated that high strain magnitude and low strain frequency are essential for tendon adaptation, with significant increases in tendon stiffness and cross-sectional area observed after 14 weeks of specific loading protocols.[1]
Additionally, different strength training regimes, such as explosive-contraction and sustained-contraction training, have been shown to increase patellar tendon stiffness and Young's modulus, with sustained-contraction training also promoting muscle hypertrophy.[2]
**Eccentric training**, which involves lengthening the muscle-tendon unit under load, has been particularly effective in improving tendon biomechanical properties. Kaux et al. found that eccentric training significantly increased the rupture force and collagen content in tendons, suggesting enhanced mechanical strength.[3]
Furthermore, the exercise-induced biochemical milieu, characterized by elevated growth hormone levels post-exercise, has been shown to enhance collagen content and tensile strength in engineered ligaments, indicating a potential mechanism for exercise-induced tendon and ligament strengthening.[4]
In summary, tendons and ligaments can be strengthened through targeted exercise regimens that include **high strain magnitude**, appropriate strain duration, and eccentric training, which collectively enhance their mechanical properties and collagen content.
References
[1] Bohm S, Mersmann F, Tettke M, Kraft M, Arampatzis A. Human Achilles Tendon Plasticity in Response to Cyclic Strain: Effect of Rate and Duration. The Journal of Experimental Biology. 2014;217(Pt 22):4010-7. doi:10.1242/jeb.112268.
[2] Massey GJ, Balshaw TG, Maden-Wilkinson TM, Tillin NA, Folland JP. Tendinous Tissue Adaptation to Explosive- Vs. Sustained-Contraction Strength Training. Frontiers in Physiology. 2018;9:1170. doi:10.3389/fphys.2018.01170.
[3] Kaux JF, Drion P, Libertiaux V, et al. Eccentric Training Improves Tendon Biomechanical Properties: A Rat Model. Journal of Orthopaedic Research : Official Publication of the Orthopaedic Research Society. 2013;31(1):119-24. doi:10.1002/jor.22202.
[4] West DW, Lee-Barthel A, McIntyre T, et al. The Exercise-Induced Biochemical Milieu Enhances Collagen Content and Tensile Strength of Engineered Ligaments. The Journal of Physiology. 2015;593(20):4665-75. doi:10.1113/JP270737.