Abstract

Background and Aim: Nowadays personal lifting assistive devices, in order to reduce the load applied from the lifted weight to muscles - in particular lower back muscles, become more widely used. The objective of our study is to analyze an empirical model of a Weight Lifting Aid Vest (WLAV) during anterior flexion (anteflexion) and studying its effects on reduction of loads on the muscles in particular back muscles. To analyze this, the intensity of signals captured from involved muscles, during the lifting in two case of with and without WLAV, was studied by the use of electromyography amplifier.

Materials and Methods: In this process, 20 subjects who lifted 10-kilogram loads in semi-squatting position were participated. With the use of a tensile-compressive spring, embedded at the back of WLAV, the amount of body stretch and deflection of their hip and knees were measured. The influence of the WLAV on satisfaction during the lifting was studied.

Results: Data were collected from electromyography findings from eight involved muscles in back, stomach and feet. The results depicted that there are a overall reduction of 25.12-percent in activation of all the muscles and particularly a reduction of 57%, 28% and 26.5% in activation of external oblique, lateral hamstring, and erector spine, respectively. In contrast, there is 11% increase in activation of Gluteus Maximus in the case of usage of WLAV.

Conclusion: WLAV can significantly mitigate the activation of back muscles and rate of load insertion on muscles) P<0.005). It also clarified the tendency of the subjects towards users WLAV) P<0.005).

Keywords: Electromyography, Load measurement, Root mean square, Weight lifting aid vest (WLAV), Muscular demand