Biomechanical approach to quantifying anticipatory postural adjustments in the elderly

Objectives: Improving balance and motor function in the elderly for preventing falling and its irreparable consequences has attracted the attention of many researchers in the field of aging. The purpose of the present is to investigate the effect of an exercise program based on Anticipatory Postural Adjustments (APAs) on postural control and motor function of the elderly. Methods & Materials: In this experimental study conducted in 2017, the study population consists of 38 eligible male elderly people with a history of falls at least once in the last six months living in Isfahan, Iran in two groups: 18 in the test group (mean age =70.4±3.2, mean height=65.3±6.2 cm, mean weight= 65.3±4.2 kg) and 15 in the control group (mean age =69.6±3.1 years, mean height =167±5.5 cm, mean weight =67.3±6.8). A foot-scan device was used to measure their postural control, and the Timed Up and Go (TUG) test was taken to measure their motor function. Data were analyzed in SPSS v. 20 software using repeated measures ANOVA at the significance level of P≤0.05. Results: The exercise program significantly improved the mean postural control scores in anterior/posterior direction from 28.1±6.2 to 20.5±2.4 (F=8.21, P≤0.05), in medial/lateral direction from 17.1±1.5 to 13.2±2.9 (F=13.4, P≤0.05), and in overall from 312.4±21.2 to 285.8±17.5 (F=10.02, P≤0.05); It also improved the mean TUG test score from 13.3±2.1 to 10.1±1.0 (F=16.02, P≤0.05). The experimental group showed a better performance than the control group after exercise in TUG test and postural control parameters (P≤0.05). Conclusion: An 8-week exercise program focused on APAs can be effective in improving postural control and motor function of the elderly.

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Age-Related Differences in Corticospinal Excitability and Anticipatory Postural Adjustments of the Trunk

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.718784 ◽

2021 ◽

Vol 13 ◽

Author(s):

Rebecca S. Rowland ◽

Ned Jenkinson ◽

Shin-Yi Chiou

Keyword(s):

Cortical Excitability ◽

Motor Evoked Potentials ◽

The Elderly ◽

Anticipatory Postural Adjustments ◽

Corticospinal Excitability ◽

Erector Spinae ◽

Postural Adjustments ◽

Old Adults ◽

Age Related ◽

Shoulder Flexion

Anticipatory postural adjustments (APAs) are a feedforward mechanism for the maintenance of postural stability and are delayed in old adults. We previously showed in young adults that APAs of the trunk induced by a fast shoulder movement were mediated, at least in part, by a cortical mechanism. However, it remains unclear the relationship between delayed APAs and motor cortical excitability in ageing. Using transcranial magnetic stimulation we examined motor evoked potentials (MEPs) of the erector spinae (ES) muscles in healthy young and old adults prior to a fast shoulder flexion task. A recognition reaction time (RRT) paradigm was used where participants responded to a visual stimulus by flexing their shoulders bilaterally as fast as possible. The activity of bilateral anterior deltoid (AD) and ES muscles was recorded using electromyography (EMG). The onset of AD and ES EMG was measured to represent RRT and APAs, respectively. We found increases in amplitudes of ES MEPs at 40 ms than 50 ms prior to the EMG onset of the AD in both groups. The amplitude of ES MEPs at 40 ms prior to the onset of AD EMG correlated with the onset of ES activity counterbalancing the perturbation induced by the shoulder task in the elderly participants only. Our findings suggest that timing of increasing corticospinal excitability prior to a self-paced perturbation becomes more relevant with ageing in modulating postural control of the trunk.

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