Article

The Achilles tendon has been seen to exhibit time-dependent conditioning when
isometric muscle actions were of a prolonged duration, compared to those involved
in dynamic activities, such as walking. Since, the effect of short duration
muscle activation associated with dynamic activities is yet to be established,
the present study aimed to investigate the effect of incidental walking activity
on Achilles tendon diametral strain. Eleven healthy male participants refrained
from physical activity in excess of the walking required to carry out necessary
daily tasks and wore an activity monitor during the 24 h study period. Achilles
tendon diametral strain, 2 cm proximal to the calcaneal insertion, was determined
from sagittal sonograms. Baseline sonographic examinations were conducted at
approximately 08:00 h followed by replicate examinations at 12 and 24 h. Walking
activity was measured as either present (1) or absent (0) and a linear weighting
function was applied to account for the proximity of walking activity to tendon
examination time. Over the course of the day the median (min, max) Achilles
tendon diametral strain was -11.4 (4.5, -25.4)%. A statistically significant
relationship was evident between walking activity and diametral strain (P<0.01)
and this relationship improved when walking activity was temporally weighted (AIC
131 to 126). The results demonstrate that the short yet repetitive loads
generated during activities of daily living, such as walking, are sufficient to
induce appreciable time-dependant conditioning of the Achilles tendon.
Implications arise for the in vivo measurement of Achilles tendon properties and
the rehabilitation of tendinopathy

Langue : ANGLAIS