Anatomical parameters for musculoskeletal modeling of the hand and wrist

A musculoskeletal model of the hand and wrist can provide valuable biomechanical and neurophysiological insights, relevant for clinicians and ergonomists. Currently, no consistent data-set exists comprising the full anatomy of these upper extremity parts. The aim of this study was to collect a complete anatomical data-set of the hand and wrist, including the intrinsic and extrinsic muscles. One right lower arm, taken from a fresh frozen female specimen, was studied. Geometrical data for muscles and joints were digitized using a 3D optical tracking system. For each muscle, optimal fiber length and physiological cross-sectional area were assessed based on muscle belly mass, fiber length, and sarcomere length. A brief description of model, in which these data were imported as input, is also provided. Anatomical data including muscle morphology and joint axes (48 muscles and 24 joints) and mechanical representations of the hand are presented. After incorporating anatomical data in the presented model, a good consistency was found between outcomes of the model and the previous experimental studies

Measuring handrim wheelchair propulsion in the lab: a critical analysis of stationary ergometers

There are many ways to simulate handrim wheelchair propulsion in the laboratory. Ideally, these would be able to, at least mechanically, simulate field conditions. This narrative review provides an overview of the lab-based equipment used in published research and critically assesses their ability to simulate and measure wheelchair propulsion performance. A close connection to the field can only be achieved if the instrument can adequately simulate frictional losses and inertia of real-life handrim wheelchair propulsion, while maintaining the ergonomic properties of the wheelchair-user interface. Lab-based testing is either performed on a treadmill or a wheelchair ergometer (WCE). For this study WCEs were divided into three categories: roller, flywheel, and integrated ergometers. In general, treadmills are mechanically realistic, but cannot simulate air drag and acceleration tasks cannot be performed; roller ergometers allow the use of the personal wheelchair, but calibration can be troublesome; flywheel ergometers can be built with commerciallyavailable parts, but inertia is fixed and the personal wheelchair cannot be used; integrated ergometers do not employ the personal wheelchair, but are suited for the implementation of different simulation models and detailed measurements. Lab-based equipment is heterogeneous and there appears to be little consensus on how to simulate field conditions

Accuracy and repeatability of wrist joint angles in boxing using an electromagnetic tracking system

© 2019, The Author(s). The hand-wrist region is reported as the most common injury site in boxing. Boxers are at risk due to the amount of wrist motions when impacting training equipment or their opponents, yet we know relatively little about these motions. This paper describes a new method for quantifying wrist motion in boxing using an electromagnetic tracking system. Surrogate testing procedure utilising a polyamide hand and forearm shape, and in vivo testing procedure utilising 29 elite boxers, were used to assess the accuracy and repeatability of the system. 2D kinematic analysis was used to calculate wrist angles using photogrammetry, whilst the data from the electromagnetic tracking system was processed with visual 3D software. The electromagnetic tracking system agreed with the video-based system (paired t tests) in both the surrogate ( 0.9). In the punch testing, for both repeated jab and hook shots, the electromagnetic tracking system showed good reliability (ICCs > 0.8) and substantial reliability (ICCs > 0.6) for flexion–extension and radial-ulnar deviation angles, respectively. The results indicate that wrist kinematics during punching activities can be measured using an electromagnetic tracking system

Comparison of Two Methods for In Vivo Estimation of the Glenohumeral Joint Rotation Center (GH-JRC) of the Patients with Shoulder Hemiarthroplasty

Determination of an accurate glenohumeral-joint rotation center (GH-JRC) from marker data is essential for kinematic and dynamic analysis of shoulder motions. Previous studies have focused on the evaluation of the different functional methods for the estimation of the GH-JRC for healthy subjects. The goal of this paper is to compare two widely used functional methods, namely the instantaneous helical axis (IHA) and symmetrical center of rotation (SCoRE) methods, for estimating the GH-JRC in vivo for patients with implanted shoulder hemiarthroplasty. The motion data of five patients were recorded while performing three different dynamic motions (circumduction, abduction, and forward flexion). The GH-JRC was determined using the CT-images of the subjects (geometric GH-JRC) and was also estimated using the two IHA and SCoRE methods. The rotation centers determined using the IHA and SCoRE methods were on average 1.47±0.62 cm and 2.07±0.55 cm away from geometric GH-JRC, respectively. The two methods differed significantly (two-tailed p-value from paired t-Test ∼0.02, post-hoc power ∼0.30). The SCoRE method showed a significant lower (two-tailed p-value from paired t-Test ∼0.03, post-hoc power ∼0.68) repeatability error calculated between the different trials of each motion and each subject and averaged across all measured subjects (0.62±0.10 cm for IHA vs. 0.43±0.12 cm for SCoRE). It is concluded that the SCoRE appeared to be a more repeatable method whereas the IHA method resulted in a more accurate estimation of the GH-JRC for patients with endoprostheses

Editorial: Adapted sports: Wheeled-mobility, exercise and health

Editorial on the Research Topic Adapted sports: wheeled-mobility, exercise and health by Vegter RJK, Veeger DHEJ, Goosey-Tolfrey VL and Leicht CA. (2002) Front. Rehabilit. Sci. 3: 1015179. doi: 10.3389/fresc.2022.1015179.</p

Skill acquisition of manual wheelchair propulsion: initial motor learning

Changes in propulsion technique due to motor learning might account for a higher mechanical efficiency (ME, the ratio of internal power over external power). The changes in ME and propulsion technique were studied in a learning experiment, three times a week for eight minutes, with nine able-bodied subjects, simulating early rehabilitation. Instrumented wheels measured three-dimensional forces and torques on the handrim. During practice peak torques were reduced, work per cycle increased, while push frequency decreased, at a stable power output and speed of the treadmill. Over the three weeks of practice propulsion technique kept changing in combination with an increase of ME. Results suggest skill acquisition because of motor learning. The rise in ME seems logically related to propulsion technique, but is not yet fully understood. More insight in motor learning and skill acquisition will contribute to understanding and optimizing rehabilitation strategies in the light of wheelchair provision in early rehabilitation

Long-term follow-up of conservatively treated midshaft clavicular fractures on functional outcome

Background: The aim of this study was to examine the long-term effect of shortening after a midshaft clavicular fracture on strength deficiency in the shoulder. Method: This study included 18 participants (14 males, 4 females) with a conservatively treated midshaft clavicular fracture. Mean age was 52.2 ± 13.8 years, range 32–76 years). The mean follow-up time was 13.5 ± 0.4 years. Participants filled in a QUICKDASH questionnaire and both clavicle lengths were measured using a caliper. The isometric strengths in internal rotation, external rotation and abduction of both arms were measured with a handheld dynamometer. Results: Average shortening of the clavicle in this group was 1.09 cm (SD 0.53). Nearly all strength measurements showed no significant difference between the shortened and the unaffected side. Multiple regression revealed a small (3N per mm length difference) but statistically significant relationship on external rotation between the relative extent of shortening of the clavicle, dominant side of the fracture and the isometric force difference between the unaffected and affected arm, F(2,15) = 5.746, p < .05, adj. R2 = .358. Over 14 years there was a reduction in mean DASH-score of 4.4 (8.8 ± 12.3; current DASH = 4.4 ± 7.7) In this group, long term effects of clavicular shortening were small. Based on these results we conclude that on the long term clavicular shortening will not result in significant strength loss