The purpose of this study was to investigate the effects of weight and grip design of concrete cellular blocks on the risk of injury to the lower back. To evaluate the proposed new design, five male participants were asked to perform simulated block laying tasks using the old-design (no grip) and the new-design (with grip). In this study, peak trunk moment, cumulative moment across experimental trial, trunk flexion angle and time required to perform the task were used as dependent variables. Results from the experiment demonstrated that weight of the block and grip/handle designs are both statistically significant (p<0.05) main factors affecting peak and cumulative moment, as well as trunk flexion angle. The time required to perform the task was not found to be a significant variable. Based on these findings, it is concluded that the proposed new design with either the grip located at the top of the concrete block or lowering the weight of the block is safer and easier to handle than the old design consisting of no grip and heavier weight.