Age differences in anticipatory and executory mechanisms of gait initiation following unexpected balance perturbations

Abstract

Purpose An age-related decline in anticipatory postural mechanisms has been reported during gait initiation; however, it is unclear whether such decline may jeopardize whole-body stability following unexpected balance perturbations. This study aimed to compare young and older individuals’ ability to generate postural responses and preserve stability in response to external waist perturbations delivered within gait initiation. Methods Ten young and ten older participants performed 10 gait initiation trials followed by 48 unperturbed and 12 perturbed trials in a random order. A stereophotogrammetric system and three force platforms were used to quantify mechanical parameters from the preparatory phase (e.g., timing and amplitude of postural adjustments) and from the stepping phase (e.g., step characteristics and dynamic stability). Activation patterns of lower leg muscles were determined by surface electromyography. Results Older participants responded to perturbation with lower increase in both magnitude (p < 0.001; η2p = 0.62) and duration (p = 0.001; η2p = 0.39) of preparatory parameters and soleus muscle activity (p < 0.001; η2p = 0.55), causing shorter (p < 0.001; η2p = 0.59) and lower (p < 0.001; η2p = 0.43) stepping, compared to young participants. Interestingly, young participants showed greater correlations between preparatory phase parameters and dynamic stability of the first step than older participants (average r of − 0.40 and − 0.06, respectively). Conclusion The results suggest that young participants took more time than older to adjust the anticipatory biomechanical response to perturbation attempting to preserve balance during stepping. In contrast, older adults were unable to modify their anticipatory adjustments in response to perturbation and mainly relied on compensatory mechanisms attempting to preserve stability via a more cautious stepping strategy.

Age-Related Changes of the Anticipatory Postural Adjustments During Gait Initiation Preceded by Vibration of Lower Leg Muscles

“…The second aspect includes the role of motor prediction in posture and locomotion coupling (Mille et al, 2014 ). Our findings may be supported by previous studies (Claudino et al, 2013 ; Laudani et al, 2021 ) indicating no postural prediction and movement coupling in older adults. It is possible that older individuals may have difficulties in utilizing APAs due to a lack of the necessary coupling between APAs and the stepping movement (Laudani et al, 2021 ) and also may have reduced usability and efficacy of APAs to ensure stability following the perturbation (Claudino et al, 2013 ).…”

“…Our findings may be supported by previous studies (Claudino et al, 2013 ; Laudani et al, 2021 ) indicating no postural prediction and movement coupling in older adults. It is possible that older individuals may have difficulties in utilizing APAs due to a lack of the necessary coupling between APAs and the stepping movement (Laudani et al, 2021 ) and also may have reduced usability and efficacy of APAs to ensure stability following the perturbation (Claudino et al, 2013 ). Another aspect concerns the age-related differences in the importance of proprioceptive and visual information for maintaining equilibrium.…”

“…During the unperturbed stepping, older adults showed significantly smaller APAs magnitude and shorter Time-to-Peak AP compared to young adults. Congruently, age-related changes in APAs were revealed in previous studies (Henriksson and Hirschfeld, 2005;Jonsson et al, 2007;Khanmohammadi et al, 2015;Laudani et al, 2021), but there are also studies which reported APAs unaffected by age (Plate et al, 2016;Lu et al, 2017). The findings of Plate et al (2016), however, do not quite reflect the age-related changes in terms of young vs. old, as they considered as young the adults with mean age 43.8 ± 2.9 years and compared them with middle-aged and older adults (mean age 55.3 ± 2.8 and 66.4 ± 4.5 years, respectively).…”

“…Our findings agree with previous studies (Rocchi et al, 2006 ; Dalton et al, 2011 ), which demonstrated scaling of APAs according to the initial posture. In line with our results, it was concluded that APAs during GI were modulated according to the proprioceptive information originating from the actual position of the body verticality which was altered by translation of support surface (Burleigh and Horak, 1996 ; Mouchnino and Blouin, 2013 ), unstable foam support surface (Chastan et al, 2010 ), the vibration of ankle muscles (Ruget et al, 2010 ), or applying resistance force at the pelvis (Mille et al, 2014 ; Laudani et al, 2021 ). As suggested in these studies, the central nervous system (CNS) utilizes feed-forward prediction for forthcoming voluntary movement, and utilizes immediate afferent information to modify the centrally initiated postural adjustments associated with stepping.…”

Impact of chronic obstructive pulmonary disease on passive viscoelastic components of the musculoarticular system

“…In fact, low viscoelastic tension worsens the balance ability more specifically in those contexts when the risk of falling is high, i.e. during transition tasks such as passing from sitting to standing, starting to walk or when standing while arm raising 12 , 47 , 49 , 62 – 64 .…”