Productivity and ergonomics are two very important facets of the manufacturing industry. However, empirically confirming the existence and magnitude of interrelationship between ergonomic workplace design and productivity can be challenging due to factors such as job rotations, unreliable ergonomic assessments, and the dynamic nature of real-world workshop environments used for research purposes. In this study, we focused on a laboratory-simulated assembly-disassembly task involving manual material handling and analyzed productivity outcomes by altering the workplace design based on the results of ergonomic evaluations conducted using the Rapid Upper Limb Assessment (RULA) method. To ensure reliability, we employed direct measurement through inertial motion capture for RULA score calculations. Our findings provide statistical evidence of enhanced productivity in relation to improvements in ergonomic exposure scores.