relaxation time, Achilles tendon, mechanical parameter, athletes

The purpose of this study was twofold: 1) to investigate the association between T2* relaxation time and Achilles tendon mechanical/material parameters (e.g., stiffness, Young’s modulus and hysteresis); and 2) to check the sensibility of the T2* in determining the differences among population, providing important insight for sports scientist and clinicians. Thirty participants (10 power athletes, 10 endurance athletes and 10 healthy participants) participated in this study. Magnetic resonance imaging (MRI) was used to quantify T2* relaxation time at rest. Ultrasound, kinetics, EMG and kinematics data were used to calculate Achilles tendon mechanical/material parameters during maximum voluntary contractions of the plantar-flexor muscles. Preliminary data on power athletes and healthy controls suggest that the Achilles tendon Young’s was higher in power athletes compared with healthy control, whereas tendon hysteresis and T2* relaxation time were lower in power athletes. Tendon stiffness was similar between populations. Our preliminary data suggest that T2* can be utilised to investigate the differences between the population in terms of material parameters (Young’s modulus and hysteresis) but not in mechanical ones (e.g. stiffness).