gms | German Medical Science

Objective: The Achilles tendon is the largest, strongest and thickest tendon in the human body [1]. Intrinsic factors such as gender seem to influence Achilles tendon thickness as males demonstrated thicker tendons than females [2], [3]. However, it is unknown whether these existing differences can be influenced by different levels of contraction at different position angles. Therefore the purpose of this study was to examine whether measuring the Achilles tendon in different levels of contraction at different angles of position can influence the tendon thickness with respect to gender. It is hypothesized that females will have thinner Achilles tendons in both levels of contraction and position angles compared to males.

Material/Methods: A cross-sectional ultrasonography study of the Achilles tendon was undertaken. Eight asymptomatic subjects (4 males & 4 females mean age 27.3±7.7 yrs.) were included. All measurements were taken with the subjects in a prone position in fixed angles at 0o and 30o plantar flexion with the assessment of an isokinetic dynamometer (Con-Trex, CMV 16 swiss). Achilles tendon thickness was measured 2 cm proximal from the calcaneus insertion [3], [4] in the two position angles during rest and at 100% maximal voluntary contraction (MVC) in longitudinal scan. Data where analysed using the non-parametric Mann-Whitney test to examine the differences between genders. Furthermore, to examine differences without dividing the group descriptive analysis was used. Main outcome measure was the median of thickness during rest and contraction (0o and 30o plantar flexion) between males and females.

Results: Ultrasonography showed no statistically significant differences of thickness between males and females during rest and contraction at 0o and 30o of plantar flexion (P>0.05). Descriptive analysis showed slightly thicker Achilles tendons but not statistically significant differences (p>0.05) at 30o plantar flexion during rest (5.47±0.67 vs 5.26±0.71 mm) and during contraction (5.60±0.86 vs 5.12±0.61 mm).

Conclusion: Measuring the Achilles tendon in different angles does not have significant influence on tendon thickness. Existing differences between males and females are not dependent on angle or contraction. Therefore ultrasonography is a valid imaging method to measure tendons in both at rest and under contraction.