The influence of contact body size on superficial and deep tissue pain perception for development of a collision dummy.

Clinical Snapshot

Key Findings

• P Value: Not reported in abstract; statistical significance implied for anaesthesia effect on small and large contact bodies

• Effect Size: Not reported quantitatively in abstract. Directional finding: medium contact body (14×14 mm²) required greatest force to induce pain; topical anaesthesia significantly increased force thresholds for small and large contact bodies

• Primary Outcome: Pain perception threshold (force in Newtons) at first pain sensation across three contact body sizes (7×7, 14×14, 24×24 mm²) and six anatomical arm regions, with and without topical anaesthesia

• Nnt Or Sensitivity: Not applicable to this experimental pain threshold study. Relevant metric would be force threshold (N) with 95% CI and inter-individual coefficient of variation — not reported in abstract

• Confidence Interval: Not reported

Clinical Application

The algometric methodology is feasible in research settings with appropriate equipment. Clinical translation of these specific findings to bedside pain assessment is limited. The primary application is industrial safety standard development (e.g., informing ISO/TS 15066 biomechanical limits for collaborative robots). Replication with larger, sex-balanced, demographically diverse samples is required before these thresholds can be incorporated into safety standards. In Australia, collaborative robot safety is governed by Safe Work Australia guidelines and AS/NZS standards aligned with ISO 10218 and ISO/TS 15066. The findings are potentially relevant to Australian manufacturing sectors with growing cobot deployment (automotive, food processing, logistics). Safe Work Australia's model Work Health and Safety laws require employers to eliminate or minimise risks from robotic systems. The RACGP and occupational medicine bodies (AFOEM) have limited direct involvement, though occupational physicians may be consulted on biomechanical injury thresholds. TGA and PBS are not relevant to this non-therapeutic study. Australian researchers at institutions such as the University of Melbourne's Centre for Ergonomics and Human Factors may find these methods relevant for local workforce safety research. Findings are most directly applicable to occupational health and safety engineers, robotics safety standards bodies, and biomechanical researchers developing collision test dummies for human-robot collaboration environments. Clinical applicability to patient care is indirect.

Abstract

The use of robots is playing an increasingly important role in industrial manufacturing. Collaborative robots operated alongside humans can pose a hazard. Pain perception as an injury risk indicator is contingent on several factors, especially contact surface, anatomical region and the difference between superficial and deep tissue pain. In this article, we have conducted an experimental load study with human subjects in which we have analyzed these factors to enable the development of a pain-sensitive dummy for testing collaborative robot against biomechanical thresholds. For the load test, we used our established algometer setup with three different contact bodies (7 × 7 mm2, 14 × 14 mm2 and 24 × 24 mm2) to evaluate six anatomical regions of the arm. Subjects were instructed to activate a switch whenever they sensed pain after starting the test procedure. The algometer increased the force in 5 N/s increments. We used topical anesthetic to distinguish between superficial and deep tissue pain. We had 11 male subjects for measurements. The greatest force had to be applied with the medium-sized contact body to induce pain perception. Local anesthetization made it necessary to increase the force of the small and large contact bodies significantly. Our finding that peak force is a reliable indicator of the perception of pain caused by the medium-sized contact body indicates that the contact body's size affects peak force magnitude significantly.

References

1. 1.Lucas, B., Behrens, R., Echterbeck, P., Pliske, G., & Piatek, S. (2026). The influence of contact body size on superficial and deep tissue pain perception for development of a collision dummy. Scientific Reports. https://doi.org/10.1067/mjd.2000.104303