Postural instability during obstacle crossing while performing manual material construction handling tasks

Abstract

Fall accidents are the most frequent accidents in construction industry and may result in serious injuries of workers involved. In order to prevent falls, it is important to understand the events leading to postural imbalances. This study aimed to investigate the impact of handling different objects during obstacle crossing in postural instability. Thirteen volunteer physically healthy subjects (age, 22 ± 1 years; body height, 177 ± 4 cm; body mass, 73 ± 7 kg) participated in the study. The experimental procedure was performed in a treadmill comprising three different tasks performed as follow: (i) walking with obstacle clearance without carrying a load, (ii) walking with obstacle clearance carrying cement bags 25 kg load (shoulder loading) and (iii) walking with obstacle clearance carrying a floor planks 18 kg load (shoulder loading). Mean force, force-time integral, pressure-time integral and contact-time of the stance foot were recorded. Additionally, the anterior-posterior and medial-lateral displacement of centre of pressure was evaluated. The results showed that handling different objects during obstacle crossing did not affect the postural stability. Thus, it seems that the technique of carrying a load in the shoulder does not impair the postural stability during obstacle crossing.