Electromyography-Based Validation of a Musculoskeletal Hand Model

Abstract

Regarding the prevention of injuries and rehabilitation of the human hand, musculoskeletal simulations using an inverse dynamics approach allow for insights of the muscle recruitment and thus acting forces on the hand. Currently, several hand models from various research groups are in use, which are mainly validated by the comparison of numerical and anatomical moment arms. In contrast to this validation and model-building technique by cadaver studies, the aim of the present study is to further validate a recently published hand model [1] by analyzing numerically calculated muscle activities in comparison to experimentally measured electromyographical signals of the muscles. Therefore, the electromyographical signals of 10 hand muscles of five test subjects performing seven different hand movements were measured. The kinematics of these tasks were used as input for the hand model, and the numerical muscle activities were computed. To analyze the relationship between simulated and measured activities, the time difference of the muscle on- and off-set points were calculated, which resulted in a mean on- and off-set time difference of 0.58 s between the experimental data and the model. The largest differences were detected for movements that mainly addressed the wrist. One major issue comparing simulated and measured muscle activities of the hand is cross-talk. Nevertheless, the results show that the hand model fits the experiment quite accurately despite some limitations and is a further step towards patient-specific modelling of the upper extremity.

A Musculoskeletal Model of the Hand and Wrist Capable of Simulating Functional Tasks

“…The kinematic simulations of passive tenodesis and active hand opening are also highly novel. Few prior studies have simulated coordinated hand motion with a model that includes the wrist and all five digits of the hand, and those that have do not evaluate functional tasks [67].…”

“…For example, two models are not dynamic models; they do not include forcegenerating parameters for the muscle-tendon actuators and do not report the mass and inertial parameters for the rigid body segments [15,16]. Whereas the remaining models are intended for dynamic simulations, implementation to simulate either grasp or pinch forces has not yet been described for two of the models [13,17] (see [13,17,67] for more details on how these models have been used). The final model has been used in several inverse-dynamics simulations of grasping [3,14,18].…”

Musculoskeletal simulation of elbow stability for common injury patterns

“…The developed elbow model was embedded in the AMS Version 7.3 and the AnyBody Managed Model Repository (AMMR) 2.2.2. 14 The AMMR full-body model including the detailed hand model from Engelhardt and Melzner et al 15,16 was used as a basis. The fact that many of the extrinsic muscles of the hand model originate in the elbow is particularly relevant in this context, as the use of the detailed hand model also allows for a more accurate calculation of the forces acting on the elbow.…”