In vivo determination of triceps surae muscle?tendon complex viscoelastic properties

Abstract

Viscoelastic properties of muscles and tendons have an important influence on human motion performance. Proper determination of these properties is essential in the analysis and modelling of human motion dynamics. The purpose of our study was to develop a method for in vivo determination of the viscoelastic properties of the entire triceps surae muscle-tendon complex (MTC) including the gastrocnemius. Ten trained male subjects participated in this study. The measurement procedure consisted of two parts: soleus and Achilles tendon stiffness and viscosity were determined in the first part while the gastrocnemius stiffness and viscosity were determined in the second part. The measurement device and the procedure have been designed in such a manner that as few human body segments move as possible during the measurement. Thus, the measurement uncertainty due to the approximation of the properties of the human body segments was minimized. Triceps surae MTC viscoelastic properties of both legs were measured for each subject. There were no significant differences in viscoelastic coefficients for left and right lower extremities; however, there were noticeable differences between subjects. The soleus stiffness coefficient was greater than the gastrocnemius stiffness coefficient by 87.6 m(-1) in average. For all subjects, soleus viscosity was equal or greater than gastrocnemius viscosity. Values of viscoelastic parameters obtained by our method can be used in the analysis and modelling of human movement in situations where the knee joint is not necessarily flexed and there is coactivation of the soleus and the gastrocnemius.

Real-time sonoelastography of the patellar and quadriceps tendons: pattern description in profesional athletes and healthy volunteers.

“…Although biomechanical studies have shown that tendon stiffness increased in tendons such as tibialis posterior or Achilles after long exercise, in the present study no differentiation was found between tendon elasticity features between professional athletes' and healthy volunteer tendons [21]. In addition, the impact of physical activity on tendon elasticity biomechanical studies also point out that viscoelastic properties of the normal Achilles tendon varies with age and sex [22,23]. As our study, Drakonaki et al did not find any difference with age or sex [12].…”

Viscoelastic properties of healthy achilles tendon are independent of isometric plantar flexion strength and cross‐sectional area

“…cSWE uses localized measurements of the tendon to determine both the shear and viscous components. The viscosity of tendon acts as the dampening mechanism [24], which means a larger viscosity leads to an increased resistance to lengthening (i.e., increased stiffness) with an increased loading rate. This effect may act as a defensive mechanism by reducing the amount of tendon stretch; on the other hand, increased viscosity enables the tendon to transmit larger forces which may increase the risk of tendon injuries.…”

A critical study on the experimental determination of stiffness and viscosity of the human triceps surae by free vibration methods

“…However, while height and weight are quite similar in what respect to this study and the study by Babic and Lenarcic, 13 are significantly higher than those corresponding to the population of the study by Fukashiro et al 12 For each load level, experimental tests were replicated four times to check the level of repeatability of measurements. For this purpose, tests were performed sequentially without altering the general configuration of the testing apparatus and taking a proper time interval lasting several seconds between each replication.…”

“…Once the values of the five unknown parameters were determined by minimizing the error functional O (equation (29)), the values of stiffness K and damping C of the equivalent vibrating system were calculated with equations (13) and (14) for the first load case. The reaction force f developed in the TS was calculated with equation (16).…”

“…For example, Fukashiro et al 12 and Babic and Lenarcic 13 considered different vibration movements: the displacement of the lower leg 12 and the rotation of the foot around the ankle articulation, 13 respectively. Although Fukashiro et al 12 and Babic and Lenarcic 13 followed the same general principle (i.e.…”