The high prevalence of work-related musculoskeletal disorders is a critical and expensive public health issue and workplace exposure to whole body vibration (WBV) is one of the major physical risk factors encountered by the population [Nachemson et al., 2000;​ Bernard, 1997;​ Bovenzi, 1996;​ Lis et al, 2007;​ Seidel, 1993]. In some professions low back disorders are more prevalent because of the presence of other risk factors like awkward postures, prolonged sitting [Lis et al., 2007] and handling of materials [Santos et al., 2008]. There are indications that, subsequent to a perturbation, impaired reflex response due to WBV exposure could allow for destabilization of the spine, possibly leading to injury [Wilder et al., 1996]. The purpose of this study is to investigate if WBV alters reflex response of trunk muscles and postural response of the spine. The secondary purpose is to investigate - if the direction of perturbation (flexion or extension or side to side) and/or time of the delivery of perturbation influences the response. Ten male subjects were selected without a history of low back pain. Subjects were exposed to two session of data collection on different days-experimental (exposed to 45 minutes of seated whole body vibration with a dominant frequency of 3 Hz) and control group (45 minutes of sitting without vibration). Subjects were exposed to sudden spinal loading before and after the exposure in different directions (lateral, flexion and extension). EMG data for trunk muscles was recorded to observe the latency of reflex muscle activation for loading protocols. The findings support the hypothesis that EMG muscle latency was increased in post-test when compared to pre-test perturbations and more so in vibration condition than in no vibration exposure. Significant effects with respect to directionality were observed in Lumbar Spinae muscle. The EMG latency recovered from the effect of perturbation after a 20 sec rest period. Studies have demonstrated that WBV exposure affects spinal proprioception [Cordo et al., 1995;​ Li et al., 2008] and neuromuscular coordination [Ng et al., 2001]. Previous research has revealed similar negative effects on EMG latency post WBV exposure [Wilder et al., 1996]. This decrease in muscle response has also been associated with chronic LBP [Radebold et al., 2001;​ Wilder et al., 1996]. In light of these results WBV can be confirmed as a potential risk factor of LBD. The present results also show that recovery of acute effects of WBV is possible with a rest period. This can be easily adopted as a workplace routine to decrease the risk of LBD. WBV did not seem to affect the margins of postural stability. This may be due to the fact the sitting is a very stable posture and small perturbations do not affect the sitting posture.