Although the effect of muscle fatigue on posture is apparent, results are inconsistent across studies and this may be due to differences in the fatigue protocol, postural stance used and/or amount of visual information provided. The purpose of this study was to test the hypothesis that fatigue would have a more pronounced effect for more difficult compared with less difficult postural tasks. Twenty-three young adults (mean age 22 ± 3 years) were asked to perform three different postural tasks on a force-platform: feet together, semi-tandem and single-leg stance, before and immediately after fatiguing the plantarflexor muscles. Three 30-s trials were performed for each postural task with eyes open and eyes closed. The fatigue protocol consisted of an isometric contraction of the plantarflexor muscles, with subjects instructed to rise on their toes and maintain this position until exhaustion. The 95% ellipse area of the center of pressure (COP), as well as the COP sway amplitudes (standard deviation) and sway velocities in the antero-posterior and medio-lateral directions were calculated. All variables were greater for each postural task performed without vision compared to with vision, with the greatest difference found during the single-leg task. For both visual conditions, all variables increased as the difficulty of the task increased. Fatigue of the plantarflexor muscles mostly affected postural sway variables during single-leg and feet together tasks. In conclusion, the reduction in postural stability with muscle fatigue of the plantarflexors does not depend on the difficulty of the postural task.
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http://dx.doi.org/10.1016/j.gaitpost.2010.07.006 | DOI Listing |
J Neurophysiol
December 2024
Department of Health Sciences and Research, Medical University of South Carolina, Charleston, SC 29425.
Deep dry needling (DDN) is a method to treat muscle trigger points (TrPs) often found in persons with neuromuscular pain and spasticity. Currently, its neurophysiological actions are not well established. Thus, to understand how DDN affects spinal cord physiology, we investigated the effects of TrP DDN on spinal reflexes.
View Article and Find Full Text PDFHum Mov Sci
December 2024
Department of Public Health and Exercise Science, Appalachian State University, Boone, NC, USA; Department of Rehabilitation Sciences, Appalachian State University, Boone, NC, USA.
Introduction: Parkinson's disease (PD) significantly impacts mobility, with gait disturbances and muscle impairments contributing to a fall risk five times higher than similarly aged adults. Falls significantly impact the quality of life in those with PD, yet the role of ankle muscle function in gait disturbances remains underexplored. This study investigated whether deficits in ankle force and steadiness contribute to gait variability and fall risk, potentially uncovering therapeutic targets for fall prevention in individuals with PD compared with age-matched older adults (OA).
View Article and Find Full Text PDFGait Posture
December 2024
Human Movement Biomechanics Research Group, Faculty of Movement and Rehabilitation Sciences, KU Leuven, Postbus 550, Leuven 3000, Belgium; Fontys University of Applied Sciences, Postbus 347, Eindhoven 5612 MA, the Netherlands. Electronic address:
Background: The plantarflexor muscles are important during walking. However, walking is not the only task that is used during daily life, and not much is known about the role of the plantarflexor muscles during other dynamic tasks. Insight into the demand of the plantarflexor muscles during different dynamic tasks might help to establish training or functional assessment for patients who experience plantarflexor weakness.
View Article and Find Full Text PDFJ Bodyw Mov Ther
March 2025
Department of Sports Medicine, Kaohsiung Medical University, Kaohsiung, 807, Taiwan; PhD Program in Biomedical Engineering, Kaohsiung Medical University, Kaohsiung, 807, Taiwan; Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, 807, Taiwan; Precision Sports Medicine and Health Promotion Center, Kaohsiung Medical University, Kaohsiung, 807, Taiwan. Electronic address:
Background: People with chronic ankle instability (CAI) have insufficient ankle dorsiflexion range of motion (DFROM) and decreases proprioception and muscle strength. Foam roller with and without vibration as a warm-up intervention may have benefits for healthy populations, but the effect on applied to injured individuals is still lacking, especially in CAI. Therefore, we aimed to compare the acute effects of three warm-up interventions, including vibration foam rolling (VR), foam rolling (FR), and static stretching (SS) in adults with CAI.
View Article and Find Full Text PDFFront Bioeng Biotechnol
November 2024
Biomechanics and Motor Control Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden.
Objective: This study was to investigate alterations in contractile properties of the ankle plantar- and dorsiflexors in post-stroke individuals. The correlation between muscle architecture parameters and contractile properties was also evaluated.
Methods: Eight post-stroke individuals and eight age-matched healthy subjects participated in the study.
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