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


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


METHODS
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.


CONCLUSIONS
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.
Centre for Health, Exercise and Sports Medicine, The School of Physiotherapy, University of Melbourne, Melbourne, Victoria, Australia. sallychild@bigpond.com
Sally
S
Child
Adam L
AL
Bryant
Ross A
RA
Clark
Kay M
KM
Crossley
D000125:Achilles Tendon / Q000000981:diagnostic imaging / Q000293:injuries* / Q000502:physiology*; D000328:Adult; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012420:Running / Q000293:injuries*; D013314:Stress, Mechanical; D052256:Tendinopathy / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014463:Ultrasonography