A variety of automation tasks require an accurate specification of forces and torques over time and space. Traditionally, only experts can provide such specifications, contrasting the need for intuitive robot programming in small and medium enterprises. Simulations and visualizations are typical approaches to increase the usability of robot programming frameworks. Thus, we extend our robot programming approach with force and torque visualizations, enabling non-experts to verify and adjust programs for in-contact tasks. In this paper, we contribute a comprehensive comparison of different force/torque visualization techniques and discuss their applications in robot programming systems. Furthermore, we evaluate visualizations of forces and torques generally as well as specifically adapted to our programming concept utilizing two user studies. Vector arrows for forces and curved arrows for torques showed promising results.