Mechanical properties of the achilles tendon aponeurosis are altered in athletes with achilles tendinopathy

Am J Sports Med. 2010 Sep;38(9):1885-93. doi: 10.1177/0363546510366234. Epub 2010 May 27.


Background: Achilles tendinopathy is a considerable problem for active people. The degenerative processes associated with tendinopathy may be associated with changes in the inherent mechanical properties of the musculotendinous unit.

Purpose: The purpose of this study was to compare Achilles tendon-aponeurosis strain between male athletes with and without Achilles tendinopathy.

Study design: Cross-sectional study; Level of evidence, 3.

Methods: Fifteen healthy men (age, 35 +/- 9 years; height, 1.78 +/- 0.05 m; mass, 79 +/- 11 kg) and 14 men with midportion Achilles tendinopathy (age, 40 +/- 8 years; height, 1.77 +/- 0.06 m; mass, 80 +/- 9 kg) who were all running over 20 km per week participated in the study. Each participant was tested in a single session that involved maximal isometric plantar flexion efforts being performed on a calf-raise apparatus while synchronous real-time ultrasonography of the triceps surae aponeurosis was recorded. Achilles tendon-aponeurosis strain (%) was calculated by dividing tendon displacement during plantar flexion by resting tendon length (intrarater reliability: intraclass correlation coefficient = .92).

Results: Participants in the Achilles tendinopathy group (5.2% +/- 2.6%) had significantly (P = .039) higher Achilles tendon-aponeurosis strain compared with the control group (3.4% +/- 1.8%). In contrast, there were no significant between-group differences for maximal isometric plantar flexion force.

Conclusion: Achilles tendon-aponeurosis strain is higher in male athletes with tendinopathy than those without. The results of this study provide a rationale for current clinical approaches to management of Achilles tendinopathy, whereby repetitive mechanical loading may impart a positive benefit through reduced compliance of the musculotendinous unit.

MeSH terms

  • Achilles Tendon / diagnostic imaging
  • Achilles Tendon / injuries*
  • Achilles Tendon / physiology*
  • Adult
  • Biomechanical Phenomena
  • Cross-Sectional Studies
  • Humans
  • Male
  • Middle Aged
  • Running / injuries*
  • Stress, Mechanical
  • Tendinopathy / diagnostic imaging
  • Tendinopathy / physiopathology*
  • Ultrasonography