Study designCase-control studyBackgroundRigid Morton’s extension (ME) are a kind of orthotics that have been used as conservative treatments of hallux rigidus (HR) named osteoarthritis, but only their effects on first metatarsophalangeal joint (MPJ) mobility and position in healthy subjects have been studied, but not on its applied forces neither in HR subjects.ObjectivesThis study sought to understand how ME orthotics with three different thicknesses could influence the kinetic first MPJ, measured dorsally using the Jack maneuver and comparing subjects with normal first MPJ mobility versus those with HR. We aimed to clarify whether tension values were different between healthy and HR subjects.Methods Fifty-eight healthy subjects were selected, of which 30 were included in the case group according to HR criteria, and 28 were included in the control group. A digital algometer was used to assess the pulled tension values (kgf) of the first MPJ during the Jack maneuver (2-mm, 4-mm, and 8-mm ME thicknesses) versus the first MPJ in the weight-bearing resting position (WRP).ResultsThe pulled tension values were reliable (ICC > 0.963). There were no statistically significant differences between the pulled tension values for the different WRP and ME conditions in the case (p = 0.969) or control (p = 0.718) groups. ConclusionsDifferent ME thicknesses had no influence on the pulled tension applied during the simulated dorsiflexion Jack maneuver.Clinical Relevance This research aims to highlight the importance of the force effects of ME when treating hallux rigidus conservatively. Our results indicate that the tension values of the first MPJ during Jack maneuver had no significant pulling force effects on ME in healthy and hallux rigidus subjects, which suggests that its prescription can be made without danger of joint overload.