A Controlled Slip: Training Propulsion via Acceleration of the Trailing Limb

Aj, Farrens; Lilley, Maria; Sergi, Fabrizio

doi:10.1101/2020.03.27.012591

Cited by 2 publications

(1 citation statement)

References 25 publications

(53 reference statements)

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“…On an active (self-paced) treadmill, the sensorimotor cortex was more engaged compared to passively walking on the (fixed speed) treadmill [13]. Additionally, self-paced treadmills have helped demonstrate that exoskeletons, visual feedback, and mechanical perturbations can shift a subject's preferred walking speed [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Speed-related but not detrended gait variability increases with more sensitive self-paced treadmill controllers at multiple slopes

Castano

Huang

2021

Preprint

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Self-paced treadmills are being used more and more to study humans walking with their self-selected gaits on a range of slopes. There are multiple options to purchase a treadmill with or implement a custom written self-paced controller, which raises questions about how self-paced controller affect treadmill speed and gait biomechanics on multiple slopes. This study investigated how different self-paced treadmill controller sensitivities affected gait parameters and variability on a decline, level, and incline slopes. We hypothesized that increasing self-paced controller sensitivity would increase gait variability on each slope. We also hypothesized that detrended variability could help mitigate differences in variability that arise from differences in speed fluctuations created by the self-paced controllers. Ten young adults walked on a self-paced treadmill using three self-paced controller sensitivities (low, medium, and high) and fixed speeds at three slopes (decline, −10°; level, 0°; incline, +10°). Within each slope, average walking speeds and spatiotemporal gait parameters were similar regardless of self-paced controller sensitivity. With higher controller sensitivities on each slope, speed fluctuations, speed variance, and step length variance increased whereas step frequency variance and step width variance were unaffected. Detrended variance was not affected by controller sensitivity suggesting that detrending variability helps mitigate differences associated with treadmill speed fluctuations. Speed-trend step length variances, however, increased with more sensitive controllers. Further, detrended step length variances were similar for self-paced and fixed speed walking, whereas self-paced walking included substantial speed-trend step length variance not present in fixed speed walking. In addition, regardless of the self-paced controller, subjects walked fastest on the level slope with the longest steps, widest steps, and least variance. Overall, our findings suggest that separating gait variability into speed-trend and detrended variability could be beneficial for interpreting gait variability among multiple self-paced treadmill studies and when comparing self-paced walking with fixed speed walking.

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Section: Introductionmentioning

confidence: 99%

Speed-related but not detrended gait variability increases with more sensitive self-paced treadmill controllers at multiple slopes

Castano

Huang

2021

Preprint

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Small Directional Treadmill Perturbations Induce Differential Gait Stability Adaptation

Huang

2021

Preprint

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Introducing unexpected perturbations to challenge gait stability is an effective approach to investigate balance control strategies. Little is known about the extent to which people can respond to small perturbations during walking. This study aimed to determine how subjects adapted gait stability to multidirectional perturbations with small magnitudes applied on a stride-by-stride basis. Ten healthy young subjects walked on a treadmill that either briefly decelerated belt speed ("stick"), accelerated belt speed ("slip"), or shifted the platform medial-laterally at right leg mid-stance. We quantified gait stability adaptation in both anterior-posterior and medial-lateral directions using margin of stability and its components, base of support and extrapolated center of mass. Gait stability was disrupted upon initially experiencing the small perturbations as margin of stability decreased in the stick, slip, and medial shift perturbations and increased in the lateral shift perturbation. Gait stability metrics were generally disrupted more for perturbations in the coincident direction. As subjects adapted their margin of stability using feedback strategies in response to the small perturbations, subjects primarily used base of support (foot placement) control in the stick and lateral shift perturbations and extrapolated center of mass control in the slip and medial shift perturbations. Gait stability metrics adapted to perturbations in both anterior-posterior and medial-lateral directions. These findings provide new knowledge about the extent of gait stability adaptation to small magnitude perturbations applied on a stride-by-stride basis and reveal potential new approaches for balance training interventions to target foot placement and center of mass control.

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A Controlled Slip: Training Propulsion via Acceleration of the Trailing Limb

Cited by 2 publications

References 25 publications

Speed-related but not detrended gait variability increases with more sensitive self-paced treadmill controllers at multiple slopes

Speed-related but not detrended gait variability increases with more sensitive self-paced treadmill controllers at multiple slopes

Small Directional Treadmill Perturbations Induce Differential Gait Stability Adaptation

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