Quantifying Age-Related Differences of Ankle Mechanical Properties Using a Robotic Device

Abstract

A deep analysis of ankle mechanical properties is a fundamental step in the design of an exoskeleton, especially if it is to be suitable for both adults and children. This study aims at assessing age-related differences of ankle properties using pediAnklebot. To achieve this aim, we enrolled 16 young adults and 10 children in an experimental protocol that consisted of the evaluation of ankle mechanical impedance and kinematic performance. Ankle impedance was measured by imposing stochastic torque perturbations in dorsi-plantarflexion and inversion-eversion directions. Kinematic performance was assessed by asking participants to perform a goaldirected task. Magnitude and anisotropy of impedance were computed using a multipleinput multiple-output system. Kinematic performance was quantified by computing indices of accuracy, smoothness, and timing. Adults showed greater magnitude of ankle impedance in both directions and for all frequencies, while the anisotropy was higher in children. By analyzing kinematics, children performed movements with lower accuracy and higher smoothness, while no differences were found for the duration of the movement. In addition, adults showed a greater ability to stop the movement when hitting the target. These findings can be useful to a proper development of robotic devices, as well as for implementation of specific training programs.

Assessing the Effects of Kata and Kumite Techniques on Physical Performance in Elite Karatekas

“…Even though the ankle mobility is shown as one predictive factor, we can speculate that also kumite athletes should take into account the training focused on the ankle mobility; in fact a poor mobility, i.e., joint rigidity, can lead to a worsening of the performance during jumping, as found in the examined jumping tests and also reported in Reference [54]. Furthermore, it has already been demonstrated as an excessive of ankle rigidity can lead to an increase of injuries [55]. From the same perspective, it would be useful the introduction of specific training sessions addressed to increase the ankle mobility during the training programs of kumite athletes, for example, through BHC (Banded Heel Cord) and BCS (Barbell Calf Smash) programs that allow improving ankle mobility with respect to traditional calf stretch technique [56].…”

Sex Differences in Human Ankle Stiffness During Standing Balance

“…Given the importance of ankle stiffness in lower extremity function, it has been extensively studied for the past decades, but most studies have focused on characterizing ankle stiffness in a single plane of movement (Kearney et al, 1990 ; Rouse et al, 2014 ). More recent studies have characterized 2D ankle stiffness in both the sagittal and frontal planes, since it contributes to not only dorsiflexion-plantarflexion (DP) movement in the sagittal plane but also inversion-eversion (IE) movement in the frontal plane (Roy et al, 2009 ; Lee et al, 2011 , 2014b ; Martelli et al, 2019 ). These studies showed that ankle stiffness is highly direction dependent, being significantly higher in DP in the sagittal plane than in IE in the frontal plane.…”

Advances in Mechanical Systems Dynamics

“…A similar approach is later developed as referring to a device for postural rehabilitation [20]. In paper [21], Martelli et al propose an analysis of ankle mechanical properties for the design of an exoskeleton to be suitable for both adults and children. Experimental tests have carried out on 16 young adults and 10 children for the evaluation of ankle mechanical impedance and kinematic performance.…”