Abstract
Prevalence of Achilles tendinopathy increases with age leading to a weaker tendon
with predisposition to rupture. Conclusive evidence of the influence of age and pathology
on Achilles tendon (AT) properties remains limited, as previous studies are based
on standardized isometric conditions. The study investigates the influence of age
and pathology on AT properties during single-leg vertical jump (SLVJ). 10 children
(C), 10 asymptomatic adults (A), and 10 tendinopathic patients (T) were included.
AT elongation [mm] from rest to maximal displacement during a SLVJ on a force-plate
was sonographically assessed. AT compliance [mm/N]) and strain [%] was calculated
by dividing elongation by peak ground reaction force [N] and length, respectively.
One-way ANOVA followed by Bonferroni post-hoc correction (α=0.05) were used to compare
C with A and A with T. AT elongation (p=0.004), compliance (p=0.001), and strain were
found to be statistically significant higher in C (27±3 mm, 0.026±0.006 [mm/N], 13±2%)
compared to A (21±4 mm, 0.017±0.005 [mm/N], 10±2%). No statistically significant differences
(p≥0.05) was found between A and T (25±5 mm, 0.019±0.004 [mm/N], 12±3%). During SLVJ,
tendon responded differently in regards to age and pathology with children having
the most compliant AT. Higher compliance found in healthy tendons might be considered
as a protective factor against load-related injuries.
Key words
children - tendinopathy - compliance - dynamic - ultrasonography
