Trunk Stabilizer Muscle Activity during Manual Lifting with and without Back Belt Use in Experienced Workers
Nopporn Kurustien MSc*,**, Keerin Mekhora PhD*, Wattana Jalayondeja PhD*, Suebsak Nanthavanij PhD***
Affiliation : * Faculty of Physical Therapy, Mahidol University, Nakhon Pathom, Thailand ** Faculty of Physical Therapy, Huachiew Chalermprakiet University, Samutprakan, Thailand *** Engineering Management Program, Sirindhorn International Institute of Technology, Thammasat University, Pathumthani, Thailand
Objective : The present study evaluated the changes in trunk-stabilizer electromyography (EMG) activities during manual
lifting with and without a back belt in experienced back belt users.
Material and Method: Eighteen participants from a warehouse and distribution center in Thailand, aged 22 to 44 years, were
assessed for trunk stabilizer muscle EMG activity, including the rectus abdominis (RA), external abdominal oblique (EO),
transversus abdominis (TrA), internal abdominal oblique (IO), erector spinae (ES), and multifidus (MF). The EMG data
were recorded during (1) rest and (2) the initial phase of manual lifting in a dynamic semi-squat posture. For both conditions,
the data were compared with and without wearing a back belt.
Results : The results showed that wearing a back belt significantly decreased TrA/IO activity during rest (p<0.01) and
significantly increased RA activity during the lifting period (p<0.05) as compared with the condition of no back belt.
Conclusion : The present study does not recommend healthy workers wear a back belt as a protective device for lower back
injury, particularly without any lifting activity. However, the back belt can be applied during lifting as it can enhance RA
activity, which may help improve abdominal pressure and is less likely cause weakness of the TrA.
Keywords : Abdominal support, Electromyography, Ergonomics, Material handling, Transversus abdominis muscle
