The effect of uncontrolled moment and short-term, repeated passive stretching on maximum ankle joint dorsiflexion angle

Abstract

Background: Trials investigating ankle joint measurement normally apply a known moment. Maximum ankle angle is affected by foot posture and stretching characteristics of the calf muscles. Objectives: To investigate whether consistent maximum ankle angles could be achieved without applying a constant moment to all subjects, and whether short, repetitive stretching of the calf muscle tendon unit would produce a difference in the maximum ankle angle. Method: Passive dorsiflexion in 14 healthy participants was captured using an optoelectronic motion analysis system, with the foot placed in 3 postures. Results: The maximum ankle angles for both the neutral and supinated positions did not differ significantly. In general, the majority of subjects (92.8%) showed no increase in the maximum ankle dorsiflexion angle following repetitive brief passive stretching. Only one subject exhibited a significant increase in maximum ankle angle at the neutral position. Conclusion: Since the range of motion of the ankle joint is clearly determined by other physical factors, the maximum ankle dorsiflexion angle can be assessed at both neutral and supinated positions without moment being controlled.