Age-related changes of postural responses to vibration of Achilles tendon

The contribution of different sensory modalities to balance control is modified by age. Postural responses to Achilles tendon vibration were investigated in order to understand the influence of age on proprioceptive input from lower legs in human stance. Postural responses to bilateral vibrations of Achilles tendon with 10 s duration were recorded at three frequencies (40, 60 and 80 Hz) in 9 healthy young (range, 24–27 years) and in 9 healthy older adults (59–70 years). Subjects were instructed to keep standing on firm surface with eyes closed. They performed three trials in each of three vibration frequencies. Postural responses were characterized by displacement of the centre of foot pressure (CoP) and by kinematics of body segments in the anterior–posterior direction. Bilateral vibrations of Achilles tendon induced backward body lean increasing with frequency of vibration and with age. The leg angle response to vibration was found similar in both groups of subjects. Slight trunk tilts from vertical position were induced by vibration in young subjects while in older subjects the trunk tilted backward together with the whole body. This observation was supported also by the minimal change of hip angle in older subjects contrary to increased hip activity in young subjects. The findings showed that the trunk and hip angle responses to proprioceptive stimulation might be a good indicator of age-related destabilization in balance control

The age-related changes of trunk responses to vibration of Achilles tendon

The contribution of different sensory modalities to balance control is modified by age. Postural responses to Achilles tendon vibration were investigated in order to understand the influence of age on proprioceptive input from lower legs in human stance. Postural responses to bilateral vibrations of Achilles tendon with 10 s duration were recorded at three frequencies (40, 60 and 80 Hz) in 9 healthy young (range, 24\u201327 years) and in 9 healthy older adults (59\u201370 years). Subjects were instructed to keep standing on firm surface with eyes closed. They performed three trials in each of three vibration frequencies. Postural responses were characterized by displacement of the centre of foot pressure (CoP) and by kinematics of body segments in the anterior\u2013posterior direction. Bilateral vibrations of Achilles tendon induced backward body lean increasing with frequency of vibration and with age. The leg angle response to vibration was found similar in both groups of subjects. Slight trunk tilts from vertical position were induced by vibration in young subjects while in older subjects the trunk tilted backward together with the whole body. This observation was supported also by the minimal change of hip angle in older subjects contrary to increased hip activity in young subjects. The findings showed that the trunk and hip angle responses to proprioceptive stimulation might be a good indicator of age-related destabilization in balance control

Effect of age on body segment tilt responses to lower leg muscle vibration

Balance impairment frequently seen in elderly represents risk factors for falls and subsequent injury, for example fractures. Aging is occasionally accompanied by age-related pathologies, like Parkinson’s disease, which hinder independent mobility and lead to postural instability. Adequate postural control depends on the integration of vestibular, somatosensory and visual information about the body motion. The analysis of changes in these sensory systems has shown agerelated deterioration and the contribution of the each sensory modalities to balance control is modified by age. Important indicators of human balance control are postural responses to altered sensory inputs. Body lean responses to vibrations of lower leg muscles were investigated in order to understand the influence of age and proprioceptive input from lower leg in human stance