Running Isn’t the Best Activity for Building Strong Achilles Tendons 🤔
While running does load the Achilles tendon, it may not provide the targeted stimulus needed for optimal strengthening. During running, peak tendon strain ranges from 4.0–4.3% (Lichtwark, 2007), occurring rapidly—in under 300 ms.
To effectively improve tendon stiffness, research suggests aiming for a strain magnitude of 4.5% to 6.5% (Radovanović, 2022; Lambrianides, 2024). This “sweet spot” promotes tendon growth and resilience.
So, how can you reach this optimal strain?
✅ Heavy isometric contractions are a simple, effective tool.
Try this protocol:
3-second isometric holds at 90% max effort
4 reps per set, 5 sets total (20 reps overall)
These longer-duration, near-maximal efforts apply greater strain to the Achilles tendon, driving adaptation for strength and stiffness.
The takeaway?
If your goal is to build stronger, more resilient Achilles tendons, don’t rely on running alone. Incorporate targeted isometric exercises to give your tendons the stimulus they need to thrive.
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📚Reference
Bohm, S., et al. (2021). "Enthalpy efficiency of the soleus muscle contributes to improvements in running economy." Proc Biol Sci 288(1943): 20202784.
Lichtwark GA, Bougoulias K, Wilson AM. Muscle fascicle and series elastic element length changes along the length of the human gastrocnemius during walking and running. J Biomech. 2007;40(1):157-64. doi: 10.1016/j.jbiomech.2005.10.035. Epub 2005 Dec 20. PMID: 16364330.
Lambrianides, Y., et al. (2024). "Evidence of different sensitivity of muscle and tendon to mechano-metabolic stimuli." Scand J Med Sci Sports 34(5): e14638.
McMahon, G. (2022). "No Strain, No Gain? The Role of Strain and Load Magnitude in Human Tendon Responses and Adaptation to Loading." The Journal of Strength & Conditioning Research: 10.1519/JSC.0000000000004288.
Radovanović, G., et al. (2022). "Evidence‑Based High‑Loading Tendon Exercise for 12 Weeks Leads to Increased Tendon Stiffness and Cross‑Sectional Area in Achilles Tendinopathy: A Controlled Clinical Trial." Sports Medicine - Open 8.