The cause of Achilles tendonitis is still unclear. Straining the tendon during physical exercise has been seen as one of the biggest pathological stimuli. Systematic overloading of the Achilles tendon above his physiological limit can cause a micro-trauma.
- A tendon heals in essentially the same way as soft tissue, going through the same inflammatory phase (1–7 days of injury), proliferative phase (7–21 days), and remodeling phase (three weeks to one year). Despite collagen maturation and remodeling, tendons are biochemically and metabolically less active than bone and muscle.