If training loads are too frequent, without rest, tendons may strain more and break down.
This study tested how the Achilles tendon responds to 12 consecutive days of high-strain loading, once per day vs. three times per day.
If you pile on heavy tendon work with little rest, does the tendon get weaker and strained even while strength improves?
Whether you’re coaching athletes, rehabbing injuries, or studying performance, this playbook will give you the clarity and confidence to train tendons smarter.
What Did the Researchers Do?
Protocol
Researchers had 11 healthy men train both legs at ~90% max effort isometrics (5×4 reps, 3s load/3s rest).
- Isometric plantarflexion contractions (pushing down against a fixed footplate so the ankle doesn’t move).
- One leg = once per day (LegT1, ~24 h rest).
- Other leg = three times per day (LegT3, only 2–3 h rest).
Measures