Sung PS, et al. - The reaction times and symmetry index of the bilateral trunk and limb muscles were compared between control individuals and individuals with low back pain (LBP) that persisted for 2 months or longer. In this study, a total of 57 right limb dominant individuals (31 healthy control individuals and 26 individuals with LBP) participated and were exposed to a slip perturbation (0.24 m/sec velocity for 1.20 cm), which caused them to move forward for 0.10 s in standing while holding a tray. Placement of the electromyography (EMG) electrodes was done on the bilateral erector spinae (ES), rectus abdominis (RA), rectus femoris, hamstring, tibialis anterior, gastrocnemius, biceps brachii (BB), and triceps brachii muscles. The control group had significantly delayed ES reaction time which might reflect a freedom of pain recurrence in the control group. Although LBP group had an increase in the asymmetry on the RA and BB muscles, its reduction was observed on the ES muscle. The LBP group showed asymmetries on the trunk and BB muscles. Researchers emphasize the necessity of considering the asymmetrical reactions in the arm-trunk muscles for rehabilitation strategies.