Local Dynamic Stability Versus Kinematic Variability of Continuous Overground and Treadmill Walking

Dingwell, Jonathan B.; Cusumano, Joseph P.; Cavanagh, Peter R.; Sternad, Dagmar

doi:10.1115/1.1336798

Cited by 573 publications

(475 citation statements)

References 28 publications

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“…Furthermore, we used treadmill walking instead of overground walking to produce robust estimates of step variability. The corollary is that treadmill walking has been found to be associated with a reduction of variability (Dingwell et al 2001), which may have masked some dual-task related gait changes as previously mentioned.…”

Section: Discussionmentioning

confidence: 87%

Effects of aging on the relationship between cognitive demand and step variability during dual-task walking

Decker

Cignetti

Hunt

et al. 2016

AGE

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A U-shaped relationship between cognitive demand and gait control may exist in dual-task situations, reflecting opposing effects of external focus of attention and attentional resource competition. The purpose of the study was twofold: to examine whether gait control, as evaluated from step-to-step variability, is related to cognitive task difficulty in a U-shaped manner and to determine whether age modifies this relationship. Young and older adults walked on a treadmill without attentional requirement and while performing a dichotic listening task under three attention conditions: nonforced (NF), forced-right (FR), and forced-left (FL). The conditions increased in their attentional demand and requirement for inhibitory control. Gait control was evaluated by the variability of step parameters related to balance control (step width) and rhythmic stepping pattern (step length and step time). A Ushaped relationship was found for step width variability in both young and older adults and for step time variability in older adults only. Cognitive performance during dual tasking was maintained in both young and older adults. The U-shaped relationship, which presumably results from a trade-off between an external focus of attention and competition for attentional resources, implies that higher-level cognitive processes are involved in walking in young and older adults. Specifically, while these processes are initially involved only in the control of (lateral) balance during gait, they become necessary for the control of (fore-aft) rhythmic stepping pattern in older adults, suggesting that attentional resources turn out to be needed in all facets of walking with aging. Finally, despite the cognitive resources required by walking, both young and older adults spontaneously adopted a Bposture second^strategy, prioritizing the cognitive task over the gait task.

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Section: Discussionmentioning

confidence: 87%

Effects of aging on the relationship between cognitive demand and step variability during dual-task walking

Decker

Cignetti

Hunt

et al. 2016

AGE

View full text Add to dashboard Cite

show abstract

“…Due to the spatial constraints of the video motion capture system; a treadmill was necessary to enable collection of kinematic data across many sequential strides. Studies have shown that a treadmill may reduce kinematic variability and increase dynamic stability of gait measures [7]. Finally, our results were limited to healthy adults.…”

Section: Discussionmentioning

confidence: 89%

The influence of gait speed on local dynamic stability of walking

2007

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The focus of this study was to examine the role of walking velocity in stability during normal gait. Local dynamic stability was quantified through the use of maximum finite-time Lyapunov exponents, λ Max . These quantify the rate of attenuation of kinematic variability of joint angle data recorded as subjects walked on a motorized treadmill at 20%, 40%, 60%, and 80% of the Froude velocity. A monotonic trend between λ Max and walking velocity was observed with smaller λ Max at slower walking velocities. Smaller λ Max indicates more stable walking dynamics. This trend was evident whether stride duration variability remained or was removed by time normalizing the data. This suggests that slower walking velocities lead to increases in stability. These results may reveal more detailed information on the behavior of the neuro-controller than variability-based analyses alone.

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“…Still, in young as well as in older subjects, around mid-swing either of these strategies could be elicited. After tripping on a treadmill the transition between strategies was more distinct (Schillings et al 2000), which might be explained by lower variation of stride length and duration in treadmill walking (Dingwell et al 2001). However, the occurrence of both strategies in the same part of the gait cycle overground suggests that strategy selection is not heavily constrained, i.e., either one could be adequate.…”

Section: Timing and Sequencing Of Muscle Activationmentioning

confidence: 98%

Control of support limb muscles in recovery after tripping in young and older subjects

2004

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Older people fall more often after tripping than young people due to a slower development of mechanical responses. This might be due to age-related changes in muscle properties, but also to changes in motor control. The purpose of the present study was to determine whether (a) timing and sequencing of muscle activation and (b) the magnitude and rate of development of muscle activation in recovery after a trip differs between young and older subjects. We focused on the support limb, as it contributes to recovery after tripping by counteracting the forward angular momentum. Ten young (25 years) and seven older (68 years) men and women walked over a platform and were tripped several times at different points in the gait cycle. Kinematics and EMG of the support limb muscles were measured. After tripping, rapid EMG responses (60-80 ms) were observed in hamstring and triceps surae muscles in both young and older subjects. A slightly increased delay (11 ms) was found only in the soleus muscle of the older subjects. The muscle activity patterns (timing and sequencing) were similar in young and older subjects, but the magnitude and rate of development of muscle activity were significantly lower in older subjects. Especially the lower rate of development of muscle activation in the support limb of older subjects is likely to reduce the rate of force generation, which can contribute to inadequate recovery responses and falls.

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Local Dynamic Stability Versus Kinematic Variability of Continuous Overground and Treadmill Walking

Cited by 573 publications

References 28 publications

Effects of aging on the relationship between cognitive demand and step variability during dual-task walking

Effects of aging on the relationship between cognitive demand and step variability during dual-task walking

The influence of gait speed on local dynamic stability of walking

Control of support limb muscles in recovery after tripping in young and older subjects

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