China
Africa
Explore chapters and articles related to this topic
Handtools
Published in Stephan Konz, Steven Johnson, Work Design, 2018
In a study with a smooth grip, a grip with grooves parallel to the pen axis, and a grip with concentric circular grooves, the grip with concentric grooves had the lowest EMG of the flexor pollicis brevis and lowest pen-point pressure (Udo et al., 1995). Udo et al. (2000) compared a conventional cylindrical 8.3 mm diameter pen with the ergonomic pen shown in Figure 14.13. The ergonomic pen had a significantly lower EMG for the flexor pollicis brevis as well as lower pain scores for thumb, forefinger, middle finger, forearm, and shoulder.
Get a grip: multi-method evaluation of handles for tablets on the shop floor
Published in Ergonomics, 2020
Michael Waechter, Danny Rueffert, Angelika C. Bullinger
The preliminary experiment with subjects (N = 5) shows that the one-handed handling of a tablet during the experimental task does not allow any degrees of freedom and can therefore be regarded as standardised (Tegtmeier 2016). During the experiment, five muscles were measured by EMG. Muscles were selected to (i) be actively involved in the process of holding, stabilising and gripping; (ii) lie on the surface in order to allow muscle activity measurement with surface EMG, with electrodes not be influenced by pressure from the device; and (iii) be clearly identifiable. The following five muscles were chosen: (1) The M. biceps brachii (BB) muscle is located in the upper arm and is responsible for the supination and flexion of the forearm, i.e. for the rotation of the wrist and flexion of the arm system, respectively. (2) The M. flexor carpi ulnaris (FCU) and the (3) M. flexor carpi radialis (FCR) allow wrist flexion in the wrist, and the (4) M. brachioradialis (BR) is responsible for flexing the forearm, especially under load. These three muscles are located in the forearm and, together with the M. biceps brachii muscle, have an indirect effect on the handling of the tablet PC. (5) The M. flexor pollicis brevis (FPB) is an intrinsic muscle and responsible for flexion of the thumb. The FPB has a direct influence on the gripping of objects (Delagi and Perotto 2011; Schuenke et al. 2007). This muscle is crucial to the opposition movement. Figure 2 shows the left hand-arm system and the examined muscles in the laboratory study.