The Comparison of Achilles Tendon Viscoelastic Properties in Elite Runners and Soccer Players

Objectives: Tendon stiffness may change depending on training and demands of sports discipline. It is important to assess tendon stiffness in order to understand tendon function during training adaptation or to optimize rehabilitation in pathological conditions. The aim of this study is to describe and to compare Achilles tendon (AT) mechanical (viscoelastic) properties of elite runners and soccer players, and demonstrate their relationship with plantar pressure. Materials and methods: A total of 17 soccer players (age: 25.8 ± 3.4 years) and 17 runners (age: 21.5 ± 4.0 years) participated in the study. Viscoelastic properties of their Achilles tendons were evaluated with a “MyotonPro” device. The measurement was performed 4 cm above the calcaneal tubercle in the prone position, while the athlete’s ankle hanged from the table in a neutral position. An “Ottobock Esco Scan” device and the “Presto-Scan” software were used for static foot pressure measurements of the athletes. The percentage of pressure figures were recorded. All evaluations were performed at the pre-season period (July-August 2018) at soccer clubs and federation facilities. Results: AT stiffness was found higher in soccer players than in runners, while elasticity was found lower (p0.05). There was no relationship of viscoelastic properties of the tendon with forefoot and rearfoot pressure in the groups. Conclusions: The storage and release of elastic energy in the Achilles tendon is important in sports and human movements. Long-term training in different sports can change the viscoelastic properties of the Achilles tendon. The plantar pressure may not affect these properties. Further studies are needed to evaluate tendon characteristics of athletes in different sports using myotonometric measurements.