Step length synergy is weaker in older adults during obstacle crossing

Kulkarni, Ashwini; Cho, HyeYoung; Rietdyk, Shirley; Ambike, Satyajit

doi:10.1016/j.jbiomech.2021.110311

Cited by 13 publications

(8 citation statements)

References 35 publications

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“…Kulkarni et al demonstrated that foot placement during gait was controlled to adjust the COG. However, this adjustment was weaker in older adults [ 17 ]. Similarly, the high values of error distance in the leaning condition indicate that the foot trajectory of the swing went through a different path each time.…”

Section: Discussionmentioning

confidence: 99%

Age-Related Changes in Accuracy and Speed of Lateral Crossing Motion: Focus on Stepping from Leaning Position

Maeda

Sudo

Shimotori

2022

IJERPH

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Fall incidents are increasing every year and prevention is necessary. Preventing falls can increase the quality of life of the elderly and decrease medical costs. Stumbling and tripping are the main causes of falls and falls in the lateral direction, causing the hip fracture. This study aimed to analyze the accuracy and speed of lateral obstacle crossing in the elderly, especially from leaning posture. Twenty healthy older adults (6 men and 14 women, aged 71.7 ± 1.5 years) and 20 healthy young adults (5 men and 15 women, aged 21.4 ± 1.2 years) participated in this study. We set four conditions (normal, fast, leaning, and leaning fast), and participants crossed the obstacle laterally ten times under each condition. The crossing motion was captured using a three-dimensional analysis system. The trajectory of the foot, landed position, step time, center of gravity of the body, and moment of the lower extremity during the swing phase were calculated and compared between older and younger adults. In the leaning condition, the step time and knee moment of the elderly were significantly longer and larger than those of young adults. From the results of the trajectory of the foot and landed position in the leaning condition, motion inconsistency of the foot was found in the elderly. We believe that it is difficult for the elderly to perform the intended crossing motion and swing quickly because of aging. This inconsistency in motion is a serious cause of falls in the elderly.

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Section: Discussionmentioning

confidence: 99%

Age-Related Changes in Accuracy and Speed of Lateral Crossing Motion: Focus on Stepping from Leaning Position

Maeda

Sudo

Shimotori

2022

IJERPH

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“…The synergy index ΔV ranges from -2 to 2. Therefore, it was z-transformed for statistical analysis (Kulkarni et al, 2021, Ambike et al, 2021): Note that ΔV = 0 translates to ΔVz = 0. We report ΔVz values in the Results section and use ΔVz values to draw inferences, consistent with most previous studies (Vaz et al, 2019).…”

Section: Methodsmentioning

confidence: 99%

“…The synergy index ΔV ranges from -2 to 2. Therefore, it was z-transformed for statistical analysis [26, 29]: …”

Section: Methodsmentioning

confidence: 99%

“…A synergy is co-variation in a redundant sets of input body variables that maintains important output variables that define task performance. The UCM method has been widely used to quantify the synergistic covariation in body variables in a variety of human movements including gait ((Cui et al, 2020, Kulkarni et al, 2021); see (Vaz et al, 2019, Latash and Huang, 2015) for recent reviews). Importantly, while identifying task-specific covariation, the UCM method simultaneously identifies the salient task variables controlled by the nervous system.…”

Section: Methodsmentioning

confidence: 99%

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Humans prioritize walking efficiency or walking stability based on environmental risk

Kulkarni

Cui

Rietdyk

et al. 2022

Preprint

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During steady-state gait, the instantaneous passive dynamics, quantified using the margin of stability in the anterior-posterior (AP) direction (MOSAP), are unstable. Although the instability indicates that substantial control will be required to reject a perturbation, the instability also allows for forward progression with low energy expenditure when the gait is unperturbed. Here, we examined whether humans control MOSAP to exploit the passive dynamics, and whether they adjust MOSAP when the threat to AP balance is increased. We computed MOSAP for six consecutive steps when healthy young adults performed unobstructed gait trials, and when they approached and crossed an obstacle. Uncontrolled manifold analysis indicated that the extrapolated center of mass and step length co-varied to maintain MOSAP for all steps during unobstructed and obstructed gait. Furthermore, the MOSAP values indicated unstable passive dynamics for all steps except while crossing the obstacle with the leading limb. Based on these results, we concluded that the MOSAP is controlled to exploit the passive dynamics and achieve forward progression at low energetic cost. Finally, MOSAP increased (indicating more stable dynamics) while approaching and crossing the obstacle with the leading limb, and then declined for later steps, indicating a fluid tradeoff between stability and energy efficiency.

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“…People with Parkinson's disease (PwPD) have difficulty in adjusting their gait to changes in the environment, especially when an obstacle appears in the path of ambulation (Galna et al, 2009). During obstacle negotiation, trips represent high risks of falls in older adults (Kulkarni et al, 2021) and, in PwPD, cause ~30% of falls (Stolze et al, 2004). A decline in basal ganglia function affects the neural commands to muscle, resulting in reductions in walking and movement speed (bradykinesia) and movement amplitude (hypokinesia) (Mirelman et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Being physically active minimizes the effects of leg muscle fatigue on obstacle negotiation in people with Parkinson’s disease

Santos

Barbieri

Orcioli‐Silva

et al. 2021

Journal of Biomechanics

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Step length synergy is weaker in older adults during obstacle crossing

Cited by 13 publications

References 35 publications

Age-Related Changes in Accuracy and Speed of Lateral Crossing Motion: Focus on Stepping from Leaning Position

Age-Related Changes in Accuracy and Speed of Lateral Crossing Motion: Focus on Stepping from Leaning Position

Humans prioritize walking efficiency or walking stability based on environmental risk

Being physically active minimizes the effects of leg muscle fatigue on obstacle negotiation in people with Parkinson’s disease

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