Purpose: The main purpose of this study was to investigate the influence of fatigue on musculoarticular stiffness (MAS) of the ankle joint across sexes.
Methods: Twenty-seven males and 26 females participated in the study. After baseline assessment of MAS and related variables, localised fatigue was induced in triceps surae using the standing heel-rise test during which the subjects were instructed to lift and drop the heel at a frequency of 0.5 Hz. When subjects were unable to continue due to exhaustion the test was terminated and another MAS test was performed soon after.
Results: Significant higher triceps surae MAS was found in men compared to women (p < .01). MAS decreased (p < .01) between pre- and post-fatigue on average from 18.0 to 17.0 KN m-1 and from 14.5 to 13.9 KN m-1 in men and women, respectively. Percentage changes revealed, however, that in relative terms the changes in all the variables evaluated were similar (p > .01) between sexes, with MAS less than 5%.
Conclusion: Despite the sex-related differences at baseline, fatigue seems to affect biomechanical properties of the ankle joint similarly in men and women.
Keywords: Fatigue; ankle; gender; muscle-tendon unit; stiffness.