Effect of Treatment Table Height on Shoulder Muscles during Ultrasound Therapy Work

Abstract

[Purpose] The purpose of this study was to propose a table height that can reduce shoulder muscle fatigue by analyzing and comparing median frequencies of shoulder muscles at different table heights when performing therapeutic ultrasounds work. [Subjects and Methods] The subjects were 63 healthy male adults who were equally and randomly assigned to a standard height group (SHG), a high height group (HHG), and a low height group (LHG). The standard table height was set at the level of the elbow joint when the subjects flexed their elbow while in a sitting position. High height and low height were set 10 cm higher and 10 cm lower, respectively, than the standard height. Muscle fatigue of the upper trapezius, middle deltoid, rhomboid, and infraspinatus of the subjects was measured during ultrasound treatment work at each table height. [Results] Median frequencies of the upper trapezius, middle deltoid, rhomboid, and infraspinatus muscles were significantly lower in the HHG than in to the LHG. [Conclusion] When therapeutic ultrasound is performed using a table that has a height lower than that of the elbow joint, the median frequency of the shoulder muscle increases, hence decreasing muscle fatigue. This way, musculoskeletal pain as a result of performing therapeutic ultrasound can be prevented.

Interventions to Mitigate Fatigue Induced by Physical Work: A Systematic Review of Research Quality and Levels of Evidence for Intervention Efficacy

“…Compared with the usual method of overhead drilling, construction workers’ subjective ratings improved significantly in association with the redesigned tools. C. Y. Kim, Kim, Kang, and Kim (2014) found that a table lower than elbow height can decrease shoulder muscle fatigue in sonographers, even during a work duration of 5 min.…”

“…Three studies provided minimal evidence for the fatigue reduction effect of tool redesign. Two high-quality RCTs (C. Y. Kim et al, 2014; Rempel, Star, Barr, Gibbons, & Janowitz, 2009) had positive findings, but one high-quality CCT (Allahyari,, Mortazavi, Khalkhali, & Sanjari, 2016) resulted in no fatigue being detected using EMG and no significant changes in subjective ratings.…”

“…C. Y. Kim, Kim, Kang, and Kim (2014) found that a table lower than elbow height can decrease shoulder muscle fatigue in sonographers, even during a work duration of 5 min. Allahyari et al (2016) compared the muscle fatigue associated with traditional and adjustable vertical looms during a 3-hr carpet weaving activity.…”