RESUMEN
Background: Joint position sense [JPS] is comprised of sensory input from several sources, including skin, joint capsule/ligaments, and muscular receptors. If the muscle receptors play a leading role in detecting joint position awareness, then muscle fatigue might yield a declination in JPS. The aim of this study was to evaluate if a sustained fatiguing contraction of the tibialis anterior [ankle dorsiflexor] could alter the ankle JPS
Methods: This was a cross-sectional study in which 40 healthy subjects [age, 23.9 +/- 2.3 years; height, 172.6 +/- 5.7 cm; weight, 67.8 +/- 4.7 kg] were recruited. Subjects were asked to recognize 2 pre-recognized positions [10 degree in dorsiflexion [DF] and 21 degree in plantarflexion [PF]] for 2 experimental conditions: normal and fatigued. Muscular fatigue was induced in the tibialis anterior of the dominant leg by using an isometric test. The average of the absolute angular error [AAE] deviations from the target positions of three trials were recorded as scores for both fatigue and non-fatigue conditions
Results: There was significant decrease in subjects' abilities to recognize active and passive repositioning of their ankle after a fatigue protocol [P=0.0001]
Conclusion: The acuity of the ankle JPS is reduced subsequent to a fatigue protocol