Contribution of Paretic and Nonparetic Limb Peak Propulsive Forces to Changes in Walking Speed in Individuals Poststroke

Hsiao, Hao-Yuan; Awad, Louis N.; Palmer, Jacqueline A.; Higginson, Jill S.; Binder‐Macleod, Stuart A.

doi:10.1177/1545968315624780

Cited by 73 publications

(82 citation statements)

References 31 publications

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“…Consistent with previous cross-sectional studies, our results showed all measurements of propulsion were correlated with walking speed (Bowden et al, 2006; Campanini and Merlo, 2009; Hsiao et al, 2015). In addition, the relationships between peak propulsive force and mean propulsive value versus walking speed were stronger compared to propulsive impulse (Figure 2 A-C).…”

Section: Discussionsupporting

confidence: 92%

“…Because asymmetry in propulsion was commonly observed in individuals poststroke (Bowden et al, 2006), propulsion from the non-paretic limb could also influence walking speed (Hsiao et al, 2015). Our results demonstrated that accounting for both limbs' peak propulsive forces and cadence further enhanced the ability of measurement of propulsion to reflect changes in walking speed (Figure 4B).…”

Section: Discussionmentioning

confidence: 99%

“…Because walking speed is associated with independence and quality of life (Dobkin et al, 2010; Perry et al, 1995), recent rehabilitation studies used walking speed as a primary outcome measure (Dobkin et al, 2010). Propulsive force is correlated to walking speed (Andriacchi et al, 1977) and increases with increased walking speed in individuals poststroke (Hsiao et al, 2015). Thus, recent poststroke rehabilitations approaches have emphasized the importance of measuring and targeting propulsion (Awad et al, 2014b; Phadke, 2012)…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of measurements of propulsion used to reflect changes in walking speed in individuals poststroke

Hsiao

Zabielski

Palmer

et al. 2016

Journal of Biomechanics

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Recent rehabilitation approaches for individuals poststroke have focused on improving walking speed because it is a reliable measurement that is associated with quality of life. Previous studies have demonstrated that propulsion, the force used to propel the body forward, determines walking speed. However, there are several different ways of measuring propulsion and no studies have identified which measurement best reflects differences in walking speed. The primary purposes of this study were to determine for individuals poststroke, which measurement of propulsion (1) is most closely related to their self-selected walking speeds and (2) best reflects changes in walking speed within a session. Participants (N=43) with chronic poststroke hemiparesis walked at their self-selected and maximal walking speeds on a treadmill. Propulsive impulse, peak propulsive force, and mean propulsive value (propulsive impulse divided by duration) were analyzed. In addition, each participant's cadence was calculated. Pearson correlation coefficients were used to determine the relationships between different measurements of propulsion versus walking speed as well as changes in propulsion versus changes in walking speed. Stepwise linear regression was used to determine which measurement of propulsion best predicted walking speed and changes in walking speed. The results showed that all 3 measurements of propulsion were correlated to walking speed, with peak propulsive force showed the strongest correlation. Similarly, when participants increased their walking speeds, changes in peak propulsive forces showed the strongest correlation to changes in walking speed. In addition, multiplying each measurement by cadence improved the correlations. The present study suggests that measuring peak propulsive force and cadence may be most appropriate of the variables studied to characterize propulsion in individuals poststroke.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evaluation of measurements of propulsion used to reflect changes in walking speed in individuals poststroke

Hsiao

Zabielski

Palmer

et al. 2016

Journal of Biomechanics

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“…GRFs were used to compute PP and non-PP and this study's primary kinetic outcome: interlimb propulsion symmetry. PP was defined as the anterior GRF measured during the paretic limb's stance phase, normalized by body weight (% bw) (65,79,86,(89)(90)(91).…”

Section: Clinical Evaluationsmentioning

confidence: 99%

A soft robotic exosuit improves walking in patients after stroke

et al. 2017

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Stroke-induced hemiparetic gait is characteristically slow and metabolically expensive. Passive assistive devices such as ankle-foot orthoses are often prescribed to increase function and independence after stroke; however, walking remains highly impaired despite-and perhaps because of-their use. We sought to determine whether a soft wearable robot (exosuit) designed to supplement the paretic limb's residual ability to generate both forward propulsion and ground clearance could facilitate more normal walking after stroke. Exosuits transmit mechanical power generated by actuators to a wearer through the interaction of garment-like, functional textile anchors and cable-based transmissions. We evaluated the immediate effects of an exosuit actively assisting the paretic limb of individuals in the chronic phase of stroke recovery during treadmill and overground walking. Using controlled, treadmill-based biomechanical investigation, we demonstrate that exosuits can function in synchrony with a wearer's paretic limb to facilitate an immediate 5.33 ± 0.91°increase in the paretic ankle's swing phase dorsiflexion and 11 ± 3% increase in the paretic limb's generation of forward propulsion (P < 0.05). These improvements in paretic limb function contributed to a 20 ± 4% reduction in forward propulsion interlimb asymmetry and a 10 ± 3% reduction in the energy cost of walking, which is equivalent to a 32 ± 9% reduction in the metabolic burden associated with poststroke walking. Relatively low assistance (~12% of biological torques) delivered with a lightweight and nonrestrictive exosuit was sufficient to facilitate more normal walking in ambulatory individuals after stroke. Future work will focus on understanding how exosuit-induced improvements in walking performance may be leveraged to improve mobility after stroke.

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“…However, this characteristic pattern of joint-level coordination in elderly gait, associated with reduced F P and thought to precede the slowing of preferred speed, is fundamentally different from that associated with walking slower. A more complete understanding of the biomechanical changes that precede the slowing of walking speed may have broad implications; similar and simultaneous interdependent changes in walking speed, F P , and joint kinetics also emerge with more acute mobility impairment such as that following stroke (Farris et al, 2015; Hsiao et al, 2015a). However, unlike the well-documented biomechanical changes due to walking speed, to our knowledge no study to date has successfully decoupled the independent effects of reducing F P on joint power generation from the neuromuscular constraints that may precipitate them.…”

Section: Introductionmentioning

confidence: 99%

The independent effects of speed and propulsive force on joint power generation in walking

Browne

Franz

2017

Journal of Biomechanics

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Walking speed is modulated using propulsive forces (FP) during push-off and both preferred speed and FP decrease with aging. However, even prior to walking slower, reduced FP may be accompanied by potentially unfavorable changes in joint power generation. For example, compared to young adults, older adults exhibit a redistribution of mechanical power generation from the propulsive plantarflexor muscles to more proximal muscles acting across the knee and hip. Here, we used visual biofeedback based on real-time FP measurements to decouple and investigate the interaction between joint-level coordination, whole-body FP, and walking speed. 12 healthy young subjects walked on a dual-belt instrumented treadmill at a range of speeds (0.9 – 1.3 m/s). We immediately calculated the average FP from each speed. Subjects then walked at 1.3 m/s while completing a series of biofeedback trials with instructions to match their instantaneous FP to their averaged FP from slower speeds. Walking slower decreased FP and total positive joint work with little effect on relative joint-level contributions. Conversely, subjects walked at a constant speed with reduced FP, not by reducing total positive joint work, but by redistributing the mechanical demands of each step from the plantarflexor muscles during push-off to more proximal leg muscles during single support. Interestingly, these naturally emergent joint- and limb-level biomechanical changes, in the absence of neuromuscular constraints, resemble those due to aging. Our findings provide important reference data to understand the presumably complex interactions between joint power generation, whole-body FP, and walking speed in our aging population.

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Contribution of Paretic and Nonparetic Limb Peak Propulsive Forces to Changes in Walking Speed in Individuals Poststroke

Cited by 73 publications

References 31 publications

Evaluation of measurements of propulsion used to reflect changes in walking speed in individuals poststroke

Evaluation of measurements of propulsion used to reflect changes in walking speed in individuals poststroke

A soft robotic exosuit improves walking in patients after stroke

The independent effects of speed and propulsive force on joint power generation in walking

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