Effects of walking-induced fatigue on postural balance and risk of falls in young and older people

Abstract

[Abstract] Gait-induced fatigue increases the variability of gait rhythmicity, which increases the risk of falls,2. However, in addition to rhythmic components, gait also has postural components. Therefore, it is relevant to know whether gait-induced fatigue affects postural balance, as poorer balance binds to an increased risk of falls3. Importantly, ageing increases the variability of gait rhythmicity and postural instability1-3. Understanding the impact of gait-induced fatigue on postural balance in young and elder healthy people (YH & EH) is of fundamental and clinical/occupational relevance. Twelve YH (20-28yrs-old) and 4 EH (60-72 yrs-old) walked over a treadmill-belt at their preferred speed for a maximum of two hours, or until withdrawal. A visual analogue scale (VAS) monitored fatigue every 5min. The Functional Reach Test evaluated dynamic balance before and after walking. For EH only, static balance was also tested on a balance platform with eyes open and close, before and after walking. All YH completed 2h-walking, EH walked for 45min (SEM 8.9). Fatigue (VAS scores) reached 3.6 points (SEM 0.7) after walking in YH, and 4.5 points (SEM 1.4) for EH (p=0.4 Mann-Whitney) despite their much shorter walking period. Dynamic balance did not change with fatigue in YH (p=0.656 Wilcoxon; PreFatigue 40.7cm SEM 2.3 vs. PostFatigue 40.3cm SEM 2.3) or EH (p=0.713 Wilcoxon; PreFatigue 36.4cm SEM 4.8 vs. PostFatigue 36.1cm SEM 4.6). In the elderly, fatigue did not affect static balance (i.e., centre of pressure displacement/30s) with eyes-open (p=0.465 Wilcoxon) PreFatigue (29.5cm SEM 5.5) vs. PostFatigue (26.8cm SEM 4.2); nor with eyes-closed (p=0.273 Wilcoxon) PreFatigue (31.9cm SEM 7.6) vs. PostFatigue (29.6cm SEM 6.2). Gait-induced fatigue does not affect postural balance in young and older humans. 1.Renner et al. Innov Aging 2020;5(1):igaa061 2.Hausdorff et al. Arch Phys Med Rehabil 1997;78(3):278-283 3.Fernie GR et al. Age Ageing 1982;11(1):11-16